CHAPTER IV.

PROGRESS OF ANALYTICAL CHEMISTRY.

Analysis, or the art of determining the constituents of which every

compound is composed, constitutes the essence of chemistry: it was

therefore attempted as soon as the science put on any thing like a

systematic form. At first, with very little success; but as knowledge

became more and more general, chemists became more expert, and

something like regular analysis began to appear. Thus, Brandt showed

that _white vitriol_ is a compound of sulphuric acid and oxide of

zinc; and Margraaf, that _selenite_ or _gypsum_ is a compound of

sulphuric acid and lime. Dr. Black made analyses of several of the

salts of magnesia, so far at least as to determine the nature of the

constituents. For hardly any attempt was made in that early period of

the art to determine the weight of the respective constituents. The

first person who attempted to lay down rules for the regular analysis

of minerals, and to reduce these rules to practice, was Bergman.

This he did in his papers "De Docimasia Minerarum Humida," "De Terra

Gemmarum," and "De Terra Tourmalini," published between the years 1777

and 1780.

To analyze a mineral, or to separate it into its constituent parts, it

is necessary in the first place, to be able to dissolve it in an acid.

Bergman showed that most minerals become soluble in muriatic acid if

they be reduced to a very fine powder, and then heated to redness, or

fused with an alkaline carbonate. After obtaining a solution in this

way he pointed out methods by which the different constituents may be

separated one after another, and their relative quantities determined.

The fusion with an alkaline carbonate required a strong red heat.

An earthenware crucible could not be employed, because at a fusing

temperature it would be corroded by the alkaline carbonate, and thus

the mineral under analysis would be contaminated by the addition of a

quantity of foreign matter. Bergman employed an iron crucible. This

effectually prevented the addition of any earthy matter. But at a red

heat the iron crucible itself is apt to be corroded by the action of

the alkali, and thus the mineral under analysis becomes contaminated

with a quantity of that metal. This iron might easily be separated

again by known methods, and would therefore be of comparatively small

consequence, provided we were sure that the mineral under examination

contained no iron; but when that happens (and it is a very frequent

occurrence), an error is occasioned which we cannot obviate. Klaproth

made a vast improvement in the art of analysis, by substituting

crucibles of fine silver for the iron crucibles of Bergman. The only

difficulty attending their use was, that they were apt to melt unless

great caution was used in heating them. Dr. Wollaston introduced

crucibles of platinum about the beginning of the present century. It

is from that period that we may date the commencement of accurate

analyzing.

Bergman's processes, as might have been expected, were rude and

imperfect. It was Klaproth who first systematized chemical analysis and

brought the art to such a state, that the processes followed could

be imitated by others with nearly the same results, thus offering a

guarantee for the accuracy of the process.

Martin Henry Klaproth, to whom chemistry lies under so many and such

deep obligations, was born at Wernigerode, on the 1st of December,

1743. His father had the misfortune to lose his whole goods by a great

fire, on the 30th of June, 1751, so that he was able to do little

or nothing for the education of his children. Martin was the second

of three brothers, the eldest of whom became a clergyman, and the

youngest private secretary at war, and keeper of the archives of the

cabinet of Berlin. Martin survived both his brothers. He procured such

meagre instruction in the Latin language as the school of Wernigerode

afforded, and he was obliged to procure his small school-fees by

singing as one of the church choir. It was at first his intention to

study theology; but the unmerited hard treatment which he met with

at school so disinclined him to study, that he determined, in his

sixteenth year, to learn the trade of an apothecary. Five years which

he was forced to spend as an apprentice, and two as an assistant in

the public laboratory in Quedlinburg, furnished him with but little

scientific information, and gave him little else than a certain

mechanical adroitness in the most common pharmaceutical preparations.

He always regarded as the epoch of his scientific instruction, the

two years which he spent in the public laboratory at Hanover, from

Easter 1766, till the same time in 1768. It was there that he first

met with some chemical books of merit, especially those of Spielman,

and Cartheuser, in which a higher scientific spirit already breathed.

He was now anxious to go to Berlin, of which he had formed a high idea

from the works of Pott, Henkel, Rose, and Margraaf. An opportunity

presenting itself about Easter, 1768, he was placed as assistant in the

laboratory of Wendland, at the sign of the Golden Angel, in the Street

of the Moors. Here he employed all the time which a conscientious

discharge of the duties of his station left him, in completing his own

scientific education. And as he considered a profounder acquaintance

with the ancient languages, than he had been able to pick up at

the school of Wernigerode, indispensable for a complete scientific

education, he applied himself with great zeal to the study of the

Greek and Latin languages, and was assisted in his studies by Mr.

Poppelbourn, at that time a preacher.

About Michaelmas, 1770, he went to Dantzig, as assistant in the public

laboratory: but in March of the following year he returned to Berlin,

as assistant in the office of the elder Valentine Rose, who was one

of the most distinguished chemists of his day. But this connexion did

not continue long; for Rose died in 1771. On his deathbed he requested

Klaproth to undertake the superintendence of his office. Klaproth not

only superintended this office for nine years with the most exemplary

fidelity and conscientiousness, but undertook the education of the

two sons of Rose, as if he had been their father. The younger died

before reaching the age of manhood: the elder became his intimate

friend, and the associate of all his scientific researches. For several

years before the death of Rose (which happened in 1808) they wrought

together, and Klaproth was seldom satisfied with the results of his

experiments till they had been repeated by Rose.

In the year 1780 Klaproth went through his trials for the office of

apothecary with distinguished applause. His thesis, "On Phosphorus and

distilled Waters," was printed in the Berlin Miscellanies for 1782.

Soon after this, Klaproth bought what had formerly been the Flemming

laboratory in Spandau-street: and he married Sophia Christiana Lekman,

with whom he lived till 1803 (when she died) in a happy state. They had

three daughters and a son, who survived their parents. He continued

in possession of this laboratory, in which he had arranged a small

work-room of his own, till the year 1800, when he purchased the room

of the Academical Chemists, in which he was enabled, at the expense of

the academy, to furnish a better and more spacious apartment for his

labours, for his mineralogical and chemical collection, and for his

lectures.

As soon as he had brought the first arrangements of his office to

perfection--an office which, under his inspection and management,

became the model of a laboratory, conducted upon the most excellent

principles, and governed with the most conscientious integrity, he

published in the various periodical works of Germany, such as "Crell's

Chemical Annals," the "Writings of the Society for the promotion of

Natural Knowledge," "Selle's Contributions to the Science of Nature

and of Medicine," "Köhler's Journal," &c.; a multitude of papers

which soon drew the attention of chemists; for example, his Essay on

Copal--on the Elastic Stone--on Proust's Sel perlée--on the Green Lead

Spar of Tschoppau--on the best Method of preparing Ammonia--on the

Carbonate of Barytes--on the Wolfram of Cornwall--on Wood Tin--on the

Violet Schorl--on the celebrated Aerial Gold--on Apatite, &c. All these

papers, which secured him a high reputation as a chemist, appeared

before 1788, when he was chosen an ordinary member of the physical

class of the Royal Berlin Academy of Sciences. The Royal Academy of

Arts had elected him a member a year earlier. From this time, every

volume of the Memoirs of the Academy, and many other periodical works

besides, contained numerous papers by this accomplished chemist; and

there is not one of them which does not furnish us with a more exact

knowledge of some one of the productions of nature or art. He has

either corrected false representations, or extended views that were

before partially known, or has revealed the composition and mixture

of the parts of bodies, and has made us acquainted with a variety of

new elementary substances. Amidst all these labours, it is difficult

to say whether we should most admire the fortunate genius, which, in

all cases, readily and easily divined the point where any thing of

importance lay concealed; or the acuteness which enabled him to find

the best means of accomplishing his object; or the unceasing labour

and incomparable exactness with which he developed it; or the pure

scientific feeling under which he acted, and which was removed at the

utmost possible distance from every selfish, every avaricious, and

every contentious purpose.

In the year 1795 he began to collect his chemical works which lay

scattered among so many periodical publications, and gave them to

the world under the title of "Beitrage zur Chemischen Kenntniss der

Mineralkörper" (Contributions to the Chemical Knowledge of Mineral

Bodies). Of this work, which consists of six volumes, the last was

published in 1815, about a year before the author's death. It contains

no fewer than two hundred and seven treatises, the most valuable part

of all that Klaproth had done for chemistry and mineralogy. It is a

pity that the sale of this work did not permit the publication of a

seventh volume, which would have included the rest of his papers, which

he had not collected, and given us a good index to the whole work,

which would have been of great importance to the practical chemist.

There is, indeed, an index to the first five volumes; but it is meagre

and defective, containing little else than the names of the substances

on which his experiments were made.

Besides his own works, the interest which he took in the labours of

others deserves to be noticed. He superintended a new edition of Gren's

Manual of Chemistry, remarkable not so much for what he added as for

what he took away and corrected. The part which he took in Wolff's

Chemical Dictionary was of great importance. The composition of every

particular treatise was by Professor Wolff; but Klaproth read over

every important article before it was printed, and assisted the editor

on all occasions with the treasures of his experience and knowledge.

Nor was he less useful to Fischer in his translation of Berthollet on

Affinity and on Chemical Statics.

These meritorious services, and the lustre which his character and

discoveries conferred on his country were duly appreciated by his

sovereign. In 1782 he had been made assessor in the Supreme College of

Medicine and of Health, which then existed. At a more recent period

he enjoyed the same rank in the Supreme Council of Medicine and of

Health; and when this college was subverted, in 1810, he became a

member of the medical deputation attached to the ministry of the

interior. He was also a member of the perpetual court commission for

medicines. His lectures, too, procured for him several municipal

situations. As soon as the public became acquainted with his great

chemical acquirements he was permitted to give yearly two private

courses of lectures on chemistry; one for the officers of the royal

artillery corps, the other for officers not connected with the army,

who wished to accomplish themselves for some practical employment.

Both of these lectures assumed afterwards a municipal character. The

former led to his appointment as professor of the Artillery Academy

instituted at Tempelhoff; and, after its dissolution, to his situation

as professor in the Royal War School. The other lecture procured for

him the professorship of chemistry in the Royal Mining Institute. On

the establishment of the university, Klaproth's lectures became those

of the university, and he himself was appointed ordinary professor of

chemistry, and member of the academical senate. From 1797 to 1810 he

was an active member of a small scientific society, which met yearly

during a few weeks for the purpose of discussing the more recondite

mysteries of the science. In the year 1811, the King of Prussia added

to all his other honours the order of the Red Eagle of the third class.

Klaproth spent the whole of a long life in the most active and

conscientious discharge of all the duties of his station, and in an

uninterrupted course of experimental investigations. He died at Berlin

on the 1st of January, 1817, in the 70th year of his age.

Among the remarkable traits in his character was his incorruptible

regard for every thing that he believed to be true, honourable,

and good; his pure love of science, with no reference whatever to

any selfish, ambitious, and avaricious feeling; his rare modesty,

undebased by the slightest vainglory or boasting. He was benevolently

disposed towards all men, and never did a slighting or contemptuous

word respecting any person fall from him. When forced to blame, he did

it briefly, and without bitterness, for his blame always applied to

actions, not to persons. His friendship was never the result of selfish

calculation, but was founded on his opinion of the personal worth of

the individual. Amidst all the unpleasant accidents of his life,

which were far from few, he evinced the greatest firmness of mind.

In his common behaviour he was pleasant and composed, and was indeed

rather inclined to a joke. To all this may be added a true religious

feeling, so uncommon among men of science of his day. His religion

consisted not in words and forms, not in positive doctrines, nor in

ecclesiastical observances, which, however, he believed to be necessary

and honourable; but in a zealous and conscientious discharge of all

his duties, not only of those which are imposed by the laws of men,

but of those holy duties of love and charity, which no human law, but

only that of God can command, and without which the most enlightened of

men is but "as sounding brass, or a tinkling cymbal." He early showed

this religious feeling by the honourable care which he bestowed on the

education of the children of Valentine Rose. Nor did he show less care

at an after-period towards his assistants and apprentices, to whom he

refused no instruction, and in whose success he took the most active

concern. He took a pleasure in every thing that was good and excellent,

and felt a lively interest in every undertaking which he believed to

be of general utility. He was equally removed from the superstition

and infidelity of his age, and carried the principles of religion, not

on his lips, but in the inmost feelings of his heart, from whence they

emanated in actions which pervaded and ennobled his whole being and

conduct.

When we take a view of the benefits which Klaproth conferred upon

chemistry, we must not look so much at the new elementary substances

which he discovered, though they must not be forgotten, as at the new

analytical methods which he introduced, the precision, and neatness,

and order, and regularity with which his analyses were conducted, and

the scrupulous fidelity with which every thing was faithfully stated as

he found it.

1. When a mineral is subjected to analysis, whatever care we take

to collect all the constituents, and to weigh them without losing

any portion whatever, it is generally found that the sum of the

constituents obtained fall a little short of the weight of the mineral

employed in the analysis. Thus, if we take 100 grains of any mineral,

and analyze it, the weights of all the constituents obtained added

together will rarely make up 100 grains, but generally somewhat

less; perhaps only 99, or even 98 grains. But some cases occur, when

the analysis of 100 grains of a mineral gives us constituents that

weigh, when added together, more than 100 grains; perhaps 105, or, in

some rare cases, as much as 110. It was the custom with Bergman, and

other analysts of his time, to consider this deficiency or surplus as

owing to errors in the analysis, and therefore to slur it over in the

statement of the analysis, by bringing the weight of the constituents,

by calculation, to amount exactly to 100 grains. Klaproth introduced

the method of stating the results exactly as he got them. He gives the

weight of mineral employed in all his analyses, and the weight of each

constituent extracted. These weights, added together, generally show a

loss, varying from two per cent. to a half per cent. This improvement

may appear at first sight trifling; yet I am persuaded that to it

we are indebted for most of the subsequent improvements introduced

into analytical chemistry. If the loss sustained was too great, it

was obvious either that the analysis had been badly performed, or

that the mineral contains some constituent which had been overlooked,

and not obtained. This laid him under the necessity of repeating the

analysis; and if the loss continued, he naturally looked out for some

constituent which his analysis had not enabled him to obtain. It was

in this way that he discovered the presence of potash in minerals; and

Dr. Kennedy afterwards, by following out his processes, discovered

soda as a constituent. It was in this way that water, phosphoric acid,

arsenic acid, fluoric acid, boracic acid, &c., were also found to exist

as constituents in various mineral bodies, which, but for the accurate

mode of notation introduced by Klaproth, would have been overlooked and

neglected.

2. When Klaproth first began to analyze mineral bodies, he found

it extremely difficult to bring them into a state capable of being

dissolved in acids, without which an accurate analysis was impossible.

Accordingly corundum, adamantine spar, and the zircon, or hyacinth,

baffled his attempts for a considerable time, and induced him to

consider the earth of corundum as of a peculiar nature. He obviated

this difficulty by reducing the mineral to an extremely fine powder,

and, after digesting it in caustic potash ley till all the water was

dissipated, raising the temperature, and bringing the whole into a

state of fusion. This fusion must be performed in a silver crucible.

Corundum, and every other mineral which had remained insoluble after

fusion with an alkaline carbonate, was found to yield to this new

process. This was an improvement of considerable importance. All

those stony minerals which contain a notable proportion of silica, in

general become soluble after having been kept for some time in a state

of ignition with twice their weight of carbonate of soda. At that

temperature the silica of the mineral unites with the soda, and the

carbonic acid is expelled. But when the quantity of silica is small,

or when it is totally absent, heating with carbonate of soda does not

answer so well. With such minerals, caustic potash or soda may be

substituted with advantage; and there are some of them that cannot

be analyzed without having recourse to that agent. I have succeeded

in analyzing corundum and chrysoberyl, neither of which, when pure,

contain any silica, by simply heating them in carbonate of soda; but

the process does not succeed unless the minerals be reduced to an

exceedingly minute powder.

3. When Klaproth discovered potash in the idocrase, and in some other

minerals, it became obvious that the old mode of rendering minerals

soluble in acids by heating them with caustic potash, or an alkaline

carbonate, could answer only for determining the quantity of silica,

and of earths or oxides, which the mineral contained; but that it could

not be used when the object was to determine its potash. This led him

to substitute _carbonate of barytes_ instead of potash or soda, or

their carbonates. After having ascertained the quantity of silica,

and of earths, and metallic oxides, which the mineral contained, his

last process to determine the potash in it was conducted in this way:

A portion of the mineral reduced to a fine powder was mixed with four

or five times its weight of carbonate of barytes, and kept for some

time (in a platinum crucible) in a red heat. By this process, the whole

becomes soluble in muriatic acid. The muriatic acid solution is freed

from silica, and afterwards from barytes, and all the earths and oxides

which it contains, by means of carbonate of ammonia. The liquid, thus

freed from every thing but the alkali, which is held in solution by the

muriatic acid, and the ammonia, used as a precipitant, is evaporated

to dryness, and the dry mass, cautiously heated in a platinum crucible

till the ammoniacal salts are driven off. Nothing now remains but the

potash, or soda, in combination with muriatic acid. The addition of

muriate of platinum enables us to determine whether the alkali be

potash or soda: if it be potash, it occasions a yellow precipitate; but

nothing falls if the alkali be soda.

This method of analyzing minerals containing potash or soda is commonly

ascribed to Rose. Fescher, in his Eloge of Klaproth, informs us that

Klaproth said to him, more than once, that he was not quite sure

whether he himself, or Rose, had the greatest share in bringing this

method to a state of perfection. From this, I think it not unlikely

that the original suggestion might have been owing to Rose, but that it

was Klaproth who first put it to the test of experiment.

The objection to this mode of analyzing is the high price of the

carbonate of barytes. This is partly obviated by recovering the barytes

in the state of carbonate; and this, in general, may be done, without

much loss. Berthier has proposed to substitute oxide of lead for

carbonate of barytes. It answers very well, is sufficiently cheap,

and does not injure the crucible, provided the oxide of lead be mixed

previously with a little nitrate of lead, to oxidize any fragments

of metallic lead which it may happen to contain. Berthier's mode,

therefore, in point of cheapness, is preferable to that of Klaproth.

It is equally efficacious and equally accurate. There are some other

processes which I myself prefer to either of these, because I find them

equally easy, and still less expensive than either carbonate of barytes

or oxide of lead. Davy's method with boracic acid is exceptionable, on

account of the difficulty of separating the boracic acid completely

again.

4. The mode of separating iron and manganese from each other employed

by Bergman was so defective, that no confidence whatever can be placed

in his results. Even the methods suggested by Vauquelin, though

better, are still defective. But the process followed by Klaproth is

susceptible of very great precision. He has (we shall suppose) the

mixture of iron and manganese to be separated from each other, in

solution, in muriatic acid. The first step of the process is to convert

the protoxide of iron (should it be in that state) into peroxide.

For this purpose, a little nitric acid is added to the solution, and

the whole heated for some time. The liquid is now to be rendered as

neutral as possible; first, by driving off as much of the excess of

acid as possible, by concentrating the liquid; and then by completing

the neutralization, by adding very dilute ammonia, till no more can be

added without occasioning a permanent precipitation. Into the liquid

thus neutralized, succinate or benzoate of ammonia is dropped, as long

as any precipitate appears. By this means, the whole peroxide of iron

is thrown down in combination with succinic, or benzoic acid, while

the whole manganese remains in solution. The liquid being filtered, to

separate the benzoate of iron, the manganese may now (if nothing else

be in the liquid) be thrown down by an alkaline carbonate; or, if the

liquid contain magnesia, or any other earthy matter, by hydrosulphuret

of ammonia, or chloride of lime.

This process was the contrivance of Gehlen; but it was made known to

the public by Klaproth, who ever after employed it in his analyses.

Gehlen employed succinate of ammonia; but Hisinger afterwards showed

that benzoate of ammonia might be substituted without any diminution of

the accuracy of the separation. This last salt, being much cheaper than

succinate of ammonia, answers better in this country. In Germany, the

succinic acid is the cheaper of the two, and therefore the best.

5. But it was not by new processes alone that Klaproth improved the

mode of analysis, though they were numerous and important; the

improvements in the apparatus contributed not less essentially to the

success of his experiments. When he had to do with very hard minerals,

he employed a mortar of flint, or rather of agate. This mortar he,

in the first place, analyzed, to determine exactly the nature of the

constituents. He then weighed it. When a very hard body is pounded in

such a mortar, a portion of the mortar is rubbed off, and mixed with

the pounded mineral. What the quantity thus abraded was, he determined

by weighing the mortar at the end of the process. The loss of weight

gave the portion of the mortar abraded; and this portion must be mixed

with the pounded mineral.

When a hard stone is pounded in an agate mortar it is scarcely possible

to avoid losing a little of it. The best method of proceeding is to

mix the matter to be pounded (previously reduced to a coarse powder

in a diamond mortar) with a little water. This both facilitates the

trituration, and prevents any of the dust from flying away; and not

more than a couple of grains of the mineral should be pounded at once.

Still, owing to very obvious causes, a little of the mineral is sure

to be lost during the pounding. When the process is finished, the

whole powder is to be exposed to a red heat in a platinum crucible,

and weighed. Supposing no loss, the weight should be equal to the

quantity of the mineral pounded together with the portion abraded

from the mortar. But almost always the weight will be found less than

this. Suppose the original weight of the mineral before pounding was

_a_, and the quantity abraded from the mortar 1; then, if nothing were

lost, the weight should be _a_ + 1; but we actually find it only _b_, a

quantity less than _a_ + 1. To determine the weight of matter abraded

from the mortar contained in this powder, we say _a_ + 1: _b_:: 1:

_x_, the quantity from the mortar in our powder, and _x_ = _b_/_a_

+ 1. In performing the analysis, Klaproth attended to this quantity,

which was silica, and subtracted it. Such minute attention may appear,

at first sight superfluous; but it is not so. In analyzing sapphire,

chrysoberyl, and some other very hard minerals, the quantity of silica

abraded from the mortar sometimes amounts to five per cent. of the

weight of the mineral; and if we were not to attend to the way in which

this silica has been introduced into the powder, we should give an

erroneous view of the constitution of the mineral under analysis. All

the analyses of chrysoberyl hitherto published, give a considerable

quantity of silica as a constituent of it. This silica, if really found

by the analysts, must have been introduced from the mortar, for pure

chrysoberyl contains no silica whatever, but is a definite compound of

glucina, alumina, and oxide of iron.

When Klaproth operated with fire, he always selected his vessels,

whether of earthenware, glass, plumbago, iron, silver, or platinum,

upon fixed principles; and showed more distinctly than chemists had

previously been aware of, what an effect the vessel frequently has upon

the result. He also prepared his reagents with great care, to ensure

their purity; for obtaining several of which in their most perfect

state, he invented several efficient methods. It is to the extreme care

with which he selected his minerals for analysis, and to the purity

of his reagents, and the fitness of his vessels for the objects in

view, that the great accuracy of his analyses is to be, in a great

measure, ascribed. He must also have possessed considerable dexterity

in operating, for when he had in view to determine any particular point

with accuracy, his results came, in general, exceedingly near the

truth. I may notice, as an example of this, his analysis of sulphate

of barytes, which was within about one-and-a-half per cent. of absolute

correctness. When we consider the looseness of the data which chemists

were then obliged to use, we cannot but be surprised at the smallness

of the error. Berzelius, in possession of better data, and possessed of

much dexterity, and a good apparatus, when he analyzed this salt many

years afterwards, committed an error of a half per cent.

Klaproth, during a very laborious life, wholly devoted to analytical

chemistry, entirely altered the face of mineralogy. When he began

his labours, chemists were not acquainted with the true composition

of a single mineral. He analyzed above 200 species, and the greater

number of them with so much accuracy, that his successors have, in

most cases, confirmed the results which he obtained. The analyses

least to be depended on, are of those minerals which contain both lime

and magnesia; for his process for separating lime and magnesia from

each other was not a good one; nor am I sure that he always succeeded

completely in separating silica and magnesia from each other. This

branch of analysis was first properly elucidated by Mr. Chenevix.

6. Analytical chemistry was, in fact, systematized by Klaproth; and it

is by studying his numerous and varied analyses, that modern chemists

have learned this very essential, but somewhat difficult art; and have

been able, by means of still more accurate data than he possessed,

to bring it to a still greater degree of perfection. But it must not

be forgotten, that Klaproth was in reality the creator of this art,

and that on that account the greatest part of the credit due to the

progress that has been made in it belongs to him.

It would be invidious to point out the particular analyses which are

least exact; perhaps they ought rather to be ascribed to an unfortunate

selection of specimens, than to any want of care or skill in the

operator. But, during his analytical processes, he discovered a variety

of new elementary substances which it may be proper to enumerate.

In 1789 he examined a mineral called _pechblende_, and found in it

the oxide of a new metal, to which he gave the name of _uranium_.

He determined its characters, reduced it to the metallic state, and

described its properties. It was afterwards examined by Richter,

Bucholz, Arfvedson, and Berzelius.

It was in the same year, 1789, that he published his analysis of the

zircon; he showed it to be a compound of silica and a new earth, to

which he gave the name of zirconia. He determined the properties of

this new earth, and showed how it might be separated from other bodies

and obtained in a state of purity. It has been since ascertained,

that it is a metallic oxide, and the metallic basis of it is now

distinguished by the name of _zirconium_. In 1795 he showed that the

_hyacinth_ is composed of the same ingredients as the zircon; and that

both, in fact, constitute only one species. This last analysis was

repeated by Morveau, and has been often confirmed by modern analytical

chemists.

It was in 1795 that he analyzed what was at that time called _red

schorl_, and now _titanite_. He showed that it was the oxide of a new

metallic body, to which he gave the name of _titanium_. He described

the properties of this new body, and pointed out its distinctive

characters. It must not be omitted, however, that he did not succeed in

obtaining oxide of titanium, or _titanic acid_, as it is now called, in

a state of purity. He was not able to separate a quantity of oxide of

iron, with which it was united, and which gave it a reddish colour. It

was first obtained pure by H. Rose, the son of his friend and pupil,

who took so considerable a part in his scientific investigations.

Titanium, in the metallic state, was some years ago discovered by Dr.

Wollaston, in the slag at the bottom of the iron furnace, at Merthyr

Tydvil, in Wales. It is a yellow-coloured, brittle, but very hard

metal, possessed of considerable beauty; but not yet applied to any

useful purpose.

In 1797 he examined the menachanite, a black sand from Cornwall, which

had been subjected to a chemical analysis by Gregor, in 1791, who had

extracted from it a new metallic substance, which Kirwan distinguished

by the name of _menachine_. Klaproth ascertained that the new metal

of Gregor was the very same as his own titanium, and that menachanite

is a compound of titanic acid and oxide of iron. Thus Mr. Gregor had

anticipated him in the discovery of titanium, though he was not aware

of the circumstance till two years after his own experiments had been

published.

In the year 1793 he published a comparative set of experiments on the

nature of carbonates of barytes and strontian; showing that their

bases are two different earths, and not the same, as had been hitherto

supposed in Germany. This was the first publication on strontian which

appeared on the continent; and Klaproth seems to have been ignorant of

what had been already done on it in Great Britain; at least, he takes

no notice of it in his paper, and it was not his character to slur over

the labours of other chemists, when they were known to him. Strontian

was first mentioned as a peculiar earth by Dr. Crawford, in his paper

on the medicinal properties of the muriate of barytes, published in

1790. The experiments on which he founded his opinions were made, he

informs us, by Mr. Cruikshanks. A paper on the same subject, by Dr.

Hope, was read to the Royal Society of Edinburgh, in 1793; but they had

been begun in 1791. In this paper Dr. Hope establishes the peculiar

characters of strontian, and describes its salts with much precision.

Klaproth had been again anticipated in his experiments on strontian;

but he could not have become aware of this till afterwards. For his own

experiments were given to the public before those of Dr. Hope.

On the 25th of January, 1798, his paper on the gold ores of

Transylvania was read at a meeting of the Academy of Sciences at

Berlin. During his analysis of these ores, he detected a new white

metal, to which he gave the name of _tellurium_. Of this metal he

describes the properties, and points out its distinguishing characters.

These ores had been examined by Muller, of Reichenstein, in the year

1782; and he had extracted from them a metal which he considered as

differing from every other. Not putting full confidence in his own

skill, he sent a specimen of his new metal to Bergman, requesting him

to examine it and give his opinion respecting its nature. All that

Bergman did was to show that the metallic body which he had got was not

antimony, to which alone, of all known metals, it bore any resemblance.

It might be inferred from this, that Muller's metal was new. But

the subject was lost sight of, till the publication of Klaproth's

experiments, in 1802, recalled it to the recollection of chemists.

Indeed, Klaproth relates all that Muller had done, with the most

perfect fairness.

In the year 1804 he published the analysis of a red-coloured mineral,

from Bastnäs in Sweden, which had been at one time confounded with

tungsten; but which the Elhuyarts had shown to contain none of that

metal. Klaproth showed that it contained a new substance, as one of

its constituents, which he considered as a new earth, and which he

called _ochroita_, because it forms coloured salts with acids. Two

years after, another analysis of the same mineral was published by

Berzelius and Hisinger. They considered the new substance which the

mineral contained as a metallic oxide, and to the unknown metallic base

they gave the name of _cerium_, which has been adopted by chemists

in preference to Klaproth's name. The characters of oxide of cerium

given by Berzelius and Hisinger, agree with those given by Klaproth

to ochroita, in all the essential circumstances. Of course Klaproth

must be considered as the discoverer of this new body. The distinction

between _earth_ and _metallic oxide_ is now known to be an imaginary

one. All the substances formerly called earths are, in fact, metallic

oxides.

Besides these new substances, which he detected by his own labours,

he repeated the analyses of others, and confirmed and extended the

discoveries they had made. Thus, when Vauquelin discovered the new

earth _glucina_, in the emerald and beryl, he repeated the analysis

of these minerals, confirmed the discovery of Vauquelin, and gave a

detailed account of the characters and properties of glucina. Gadolin

had discovered another new earth in the mineral called gadolinite. This

discovery was confirmed by the analysis of Ekeberg, who distinguished

the new earth by the name of yttria. Klaproth immediately repeated

the analysis of the gadolinite, confirmed the results of Ekeberg's

analysis, and examined and described the properties of _yttria_.

When Dr. Kennedy discovered soda in basalt, Klaproth repeated the

analysis of this mineral, and confirmed the results obtained by the

Edinburgh analyst.

But it would occupy too much room, if I were to enumerate every example

of such conduct. Whoever will take the trouble to examine the different

volumes of the Beitrage, will find several others not less striking or

less useful.

The service which Klaproth performed for mineralogy, in Germany, was

performed equally in France by the important labours of M. Vauquelin.

It was in France, in consequence of the exertions of Romé de Lisle,

and the mathematical investigations of the Abbé Hauy, respecting

the structure of crystals, which were gradually extended over the

whole mineral kingdom, that the reform in mineralogy, which has now

become in some measure general, originated. Hauy laid it down as a

first principle, that every mineral species is composed of the same

constituents united in the same proportion. He therefore considered

it as an object of great importance, to procure an exact chemical

analysis of every mineral species. Hitherto no exact analysis of

minerals had been performed by French chemists; for Sage, who was the

chemical mineralogist connected with the academy, satisfied himself

with ascertaining the nature of the constituents of minerals, without

determining their proportions. But Vauquelin soon displayed a knowledge

of the mode of analysis, and a dexterity in the use of the apparatus

which he employed, little less remarkable than that of Klaproth himself.

Of Vauquelin's history I can give but a very imperfect account, as I

have not yet had an opportunity of seeing any particulars of his life.

He was a peasant-boy of Normandy, with whom Fourcroy accidentally met.

He was pleased with his quickness and parts, and delighted with the

honesty and integrity of his character. He took him with him to Paris,

and gave him the superintendence of his laboratory. His chemical

knowledge speedily became great, and his practice in experimenting

gave him skill and dexterity: he seems to have performed all the

analytical experiments which Fourcroy was in the habit of publishing.

He speedily became known by his publications and discoveries. When the

scientific institutions were restored or established, after the death

of Robespierre, Vauquelin became a member of the Institute and chemist

to the School of Mines. He was made also assay-master of the Mint.

He was a professor of chemistry in Paris, and delivered, likewise,

private lectures, and took in practical pupils into his laboratory.

His laboratory was of considerable size, and he was in the habit of

preparing both medicines and chemical reagents for sale. It was he

chiefly that supplied the French chemists with phosphorus, &c., which

cannot be conveniently prepared in a laboratory fitted up solely for

scientific purposes.

Vauquelin was by far the most industrious of all the French chemists,

and has published more papers, consisting of mineral, vegetable, and

animal analyses, than any other chemist without exception. When he had

the charge of the laboratory of the School of Mines, Hauy was in the

habit of giving him specimens of all the different minerals which he

wished analyzed. The analyses were conducted with consummate skill,

and we owe to him a great number of improvements in the methods of

analysis. He is not entitled to the same credit as Klaproth, because he

had the advantage of many analyses of Klaproth to serve him as a guide.

But he had no model before him in France; and both the apparatus used

by him, and the reagents which he employed, were of his own contrivance

and preparation. I have sometimes suspected that his reagents were not

always very pure; but I believe the true reason of the unsatisfactory

nature of many of his analyses, is the bad choice made of the specimens

selected for analysis. It is obvious from his papers, that Vauquelin

was not a mineralogist; for he never attempts a description of the

mineral which he subjects to analysis, satisfying himself with the

specimen put into his hands by Hauy. Where that specimen was pure, as

was the case with emerald and beryl, his analysis is very good; but

when the specimen was impure or ill-chosen, then the result obtained

could not convey a just notion of the constituents of the mineral.

That Hauy would not be very difficult to please in his selection of

specimens, I think myself entitled to infer from the specimens of

minerals contained in his own cabinet, many of which were by no means

well selected. I think, therefore, that the numerous analyses published

by Vauquelin, in which the constituents assigned by him are not those,

or, at least, not in the same proportions, as have been found by

succeeding analysts, are to be ascribed, not to errors in the analysis,

which, on the contrary, he always performed carefully, and with the

requisite attention to precision, but to the bad selection of specimens

put into his hand by Hauy, or those other individuals who furnished him

with the specimens which he employed in his analyses. This circumstance

is very much to be deplored; because it puts it out of our power to

confide in an analysis of Vauquelin, till it has been repeated and

confirmed by somebody else.

Vauquelin not only improved the analytical methods, and reduced the art

to a greater degree of simplicity and precision, but he discovered,

likewise, new elementary bodies.

The red lead ore of Siberia had early drawn the attention of chemists,

on account of its beauty; and various attempts had been made to analyze

it. Among others, Vauquelin tried his skill upon it, in 1789, in

concert with M. Macquart, who had brought specimens of it from Siberia;

but at that time he did not succeed in determining the nature of the

acid with which the oxide of lead was combined in it. He examined

it again in 1797, and now succeeded in separating an acid to which,

from the beautiful coloured salts which it forms, he gave the name of

_chromic_. He determined the properties of this acid, and showed that

its basis was a new metal to which he gave the name of _chromium_. He

succeeded in obtaining this metal in a separate state, and showed that

its protoxide is an exceedingly beautiful green powder. This discovery

has been of very great importance to different branches of manufacture

in this country. The green oxide is used pretty extensively in painting

green on porcelain. It constitutes an exceedingly beautiful green

pigment, very permanent, and easily applied. The chromic acid, when

combined with oxide of lead, forms either a yellow or an orange colour

upon cotton cloth, both very fixed and exceedingly beautiful colours.

In that way it is extensively used by the calico-printers; and the

bichromate of potash is prepared, in a crystalline form, to a very

considerable amount, both in Glasgow and Lancashire, and doubtless in

other places.

Vauquelin was requested by Hauy to analyze the _beryl_, a beautiful

light-green mineral, crystallized in six-sided prisms, which occurs

not unfrequently in granite rocks, especially in Siberia. He found it

to consist chiefly of silica, united to alumina, and to another earthy

body, very like alumina in many of its properties, but differing in

others. To this new earth he gave the name of _glucina_, on account

of the sweet taste of its salts; a name not very appropriate, as

alumina, yttria, lead, protoxide of chromium, and even protoxide of

iron, form salts which are distinguished by a sweet taste likewise.

This discovery of glucina confers honour on Vauquelin, as it shows

the care with which his analyses must have been conducted. A careless

experimenter might easily have confounded _glucina_ with _alumina_.

Vauquelin's mode of distinguishing them was, to add sulphate of potash

to their solution in sulphuric acid. If the earth in solution was

alumina, crystals of alum would form in the course of a short time; but

if the earth was glucina, no such crystals would make their appearance,

alumina being the basis of alum, and not glucina. He showed, too, that

glucina is easily dissolved in a solution of carbonate of ammonia,

while alumina is not sensibly taken up by that solution.

Vauquelin died in 1829, after having reached a good old age. His

character was of the very best kind, and his conduct had always been

most exemplary. He never interfered with politics, and steered his way

through the bloody period of the revolution, uncontaminated by the

vices or violence of any party, and respected and esteemed by every

person.

Mr. Chenevix deserves also to be mentioned as an improver of analytical

chemistry. He was an Irish gentleman, who happened to be in Paris

during the reign of terror, and was thrown into prison and put into the

same apartment with several French chemists, whose whole conversation

turned upon chemical subjects. He caught the infection, and, after

getting out of prison, began to study the subject with much energy and

success, and soon distinguished himself as an analytical chemist.

His analysis of corundum and sapphire, and his observations on the

affinity between magnesia and silica, are valuable, and led to

considerable improvements in the method of analysis. His analyses of

the arseniates of copper, though he demonstrated that several different

species exist, are not so much to be depended on; because his method

of separating and estimating the quantity of arsenic acid is not

good. This difficult branch of analysis was not fully understood till

afterwards.

Chenevix was for several years a most laborious and meritorious

chemical experimenter. It is much to be regretted that he should

have been induced, in consequence of the mistake into which he fell

respecting palladium, to abandon chemistry altogether. Palladium was

originally made known to the public by an anonymous handbill which was

circulated in London, announcing that _palladium_, or new silver, was

on sale at Mrs. Forster's, and describing its properties. Chenevix, in

consequence of the unusual way in which the discovery was announced,

naturally considered it as an imposition on the public. He went to

Mrs. Forster's, and purchased the whole palladium in her possession,

and set about examining it, prepossessed with the idea that it was an

alloy of some two known metals. After a laborious set of experiments,

he considered that he had ascertained it to be a compound of platinum

and mercury, or an amalgam of platinum made in a peculiar way, which

he describes. This paper was read at a meeting of the Royal Society by

Dr. Wollaston, who was secretary, and afterwards published in their

Transactions. Soon after this publication, another anonymous handbill

was circulated, offering a considerable price for every grain of

palladium _made_ by Mr. Chenevix's process, or by any other process

whatever. No person appearing to claim the money thus offered, Dr.

Wollaston, about a year after, in a paper read to the Royal Society,

acknowledged himself to have been the discoverer of palladium, and

related the process by which he had obtained it from the solution of

crude platina in aqua regia. There could be no doubt after this, that

palladium was a peculiar metal, and that Chenevix, in his experiments,

had fallen into some mistake, probably by inadvertently employing

a solution of palladium, instead of a solution of his amalgam of

platinum; and thus giving the properties of the one solution to the

other. It is very much to be regretted, that Dr. Wollaston allowed Mr.

Chenevix's paper to be printed, without informing him, in the first

place, of the true history of palladium: and I think that if he had

been aware of the bad consequences that were to follow, and that it

would ultimately occasion the loss of Mr. Chenevix to the science, he

would have acted in a different manner. I have more than once conversed

with Dr. Wollaston on the subject, and he assured me that he did every

thing that he could do, short of betraying his secret, to prevent

Mr. Chenevix from publishing his paper; that he had called upon, and

assured him, that he himself had attempted his process without being

able to succeed, and that he was satisfied that he had fallen into

some mistake. As Mr. Chenevix still persisted in his conviction of the

accuracy of his own experiments after repeated warnings, perhaps it

is not very surprising that Dr. Wollaston allowed him to publish his

paper, though; had he been aware of the consequences to their full

extent, I am persuaded that he would not have done so. It comes to be a

question whether, had Dr. Wollaston informed him of the whole secret,

Mr. Chenevix would have been convinced.

Another chemist, to whom the art of analyzing minerals lies under

great obligations, is Dr. Frederick Stromeyer, professor of chemistry

and pharmacy, in the University of Gottingen. He was originally a

botanist, and only turned his attention to chemistry when he had the

offer of the chemical chair at Gottingen. He then went to Paris, and

studied practical chemistry for some years in Vauquelin's laboratory.

He has devoted most of his attention to the analysis of minerals; and

in the year 1821 published a volume of analyses under the title of

"Untersuchungen über die Mischung der Mineralkörper und anderer damit

verwandten Substanzen." It contains thirty analyses, which constitute

perfect models of analytical sagacity and accuracy. After Klaproth's

Beitrage, no book can be named more highly deserving the study of the

analytical chemist than Stromeyer's Untersuchungen.

The first paper in this work contains the analysis of arragonite.

Chemists had not been able to discover any difference in the chemical

constitution of arragonite and calcareous spar, both being compounds of

Lime 3·5

Carbonic acid 2·75

Yet the minerals differ from each other in their hardness, specific

gravity, and in the shape of their crystals. Many attempts had been

made to account for this difference in characters between these two

minerals, but in vain. Mr. Holme showed that arragonite contained

about one per cent. of water, which is wanting in calcareous spar;

and that when arragonite is heated, it crumbles into powder, which is

not the case with calcareous spar. But it is not easy to conceive how

the addition of one per cent. of water should increase the specific

gravity and the hardness, and quite alter the shape of the crystals

of calcareous spar. Stromeyer made a vast number of experiments

upon arragonite, with very great care, and the result was, that the

arragonite from Bastenes, near Dax, in the department of Landes, and

likewise that from Molina, in Arragon, was a compound of

96 carbonate of lime

4 carbonate of strontian.

This amounts to about thirty-five atoms of carbonate of lime, and

one atom of carbonate of strontian. Now as the hardness and specific

gravity of carbonate of strontian is greater than that of carbonate of

lime, we can see a reason why arragonite should be heavier and harder

than calcareous spar. More late researches upon different varieties

of arragonite enabled him to ascertain that this mineral exists with

different proportions of carbonate of strontian. Some varieties contain

only 2 per cent., some only 1 per cent., and some only 0·75, or even

0·5 per cent.; but he found no specimen among the great number which

he analyzed totally destitute of carbonate of strontian. It is true

that Vauquelin afterwards examined several varieties in which he

could detect no strontian whatever; but as Vauquelin's mineralogical

knowledge was very deficient, it comes to be a question, whether the

minerals analyzed by him were really arragonites, or only varieties of

calcareous spar.

To Professor Stromeyer we are likewise indebted for the discovery of

the new metal called _cadmium_; and the discovery does great credit

to his sagacity and analytical skill. He is inspector-general of the

apothecaries for the kingdom of Hanover. While discharging the duties

of his office at Hildesheim, in the year 1817, he found that the

carbonate of zinc had been substituted for the oxide of zinc, ordered

in the Hanoverian Pharmacopœia. This carbonate of zinc was manufactured

at Salzgitter. On inquiry he learned from Mr. Jost, who managed that

manufactory, that they had been obliged to substitute the carbonate

for the oxide of zinc, because the oxide had a yellow colour which

rendered it unsaleable. On examining this oxide, Stromeyer found

that it owed its yellow colour to the presence of a small quantity of

the oxide of a new metal, which he separated, reduced, and examined,

and to which he gave the name of _cadmium_, because it occurs usually

associated with zinc. The quantity of cadmium which he was able to

obtain from this oxide of zinc was but small. A fortunate circumstance,

however, supplied him with an additional quantity, and enabled him to

carry his examination of cadmium to a still greater length. During the

apothecaries' visitation in the state of Magdeburg, there was found,

in the possession of several apothecaries, a preparation of zinc

from Silesia, made in Hermann's laboratory at Schönebeck, which was

confiscated on the supposition that it contained arsenic, because its

solution gave a yellow precipitate with sulphuretted hydrogen, which

was considered as orpiment. This statement could not be indifferent

to Mr. Hermann, as it affected the credit of his manufactory;

especially as the medicinal counsellor, Roloff, who had assisted

at the visitation, had drawn up a statement of the circumstances

which occasioned the confiscation, and caused it to be published in

Hofeland's Medical Journal. He subjected the suspected oxide to a

careful examination; but he could not succeed in detecting any arsenic

in it. He then requested Roloff to repeat his experiments. This he

did; and now perceived that the precipitate, which he had taken for

orpiment, was not so in reality, but owed its existence to the presence

of another metallic oxide, different from arsenic and probably new.

Specimens of this oxide of zinc, and of the yellow precipitate, were

sent to Stromeyer for examination, who readily recognised the presence

of cadmium, and was able to extract from it a considerable quantity of

that metal.

It is now nine years since the first volume of the Untersuchungen was

published. All those who are interested in analytical chemistry are

anxious for the continuance of that admirable work. By this time he

must have collected ample materials for an additional volume; and it

could not but add considerably to a reputation already deservedly high.

There is no living chemist, to whom analytical chemistry lies under

greater obligations than to Berzelius, whether we consider the number

or the exactness of the analyses which he has made.

Jacob Berzelius was educated at Upsala, when Professor Afzelius,

a nephew of Bergman, filled the chemical chair, and Ekeberg was

_magister docens_ in chemistry. Afzelius began his chemical career with

considerable _éclat_, his paper on sulphate of barytes being possessed

of very considerable merit. But he is said to have soon lost his

health, and to have sunk, in consequence, into listless inactivity.

Andrew Gustavus Ekeberg was born in Stockholm, on the 16th of January,

1767. His father was a captain in the Swedish navy. He was educated at

Calmar; and in 1784 went to Upsala, where he devoted himself chiefly

to the study of mathematics. He took his degree in 1788, when he wrote

a thesis "De Oleis Seminum expressis." In 1789 he went to Berlin; and

on his return, in 1790, he gave a specimen of his poetical talents,

by publishing a poem entitled "Tal öfver Freden emellan Sverige och

Ryssland" (Discourse about the Peace between Sweden and Russia). After

this he turned his attention to chemistry; and in 1794 was made _chemiæ

docens_. In this situation he continued till 1813, when he died on

the 11th of February. He had been in such bad health for some time

before his death, as to be quite unable to discharge the duties of his

situation. He published but little, and that little consisted almost

entirely of chemical analyses.

His first attempt was on phosphate of lime; then he wrote a paper

on the analysis of the topaz, the object of which was to explain

Klaproth's method of dissolving hard stony bodies.

He made an analysis of gadolinite, and determined the chemical

properties of yttria. During these experiments he discovered the new

metal to which he gave the name of _tantalum_, and which Dr. Wollaston

afterwards showed to be the same with the _columbium_ of Mr. Hatchett.

He also published an analysis of the automalite, of an ore of titanium,

and of the mineral water of Medevi. In this last analysis he was

assisted by Berzelius, who was then quite unknown to the chemical world.

Berzelius has been much more industrious than his chemical

contemporaries at Upsala. His first publication was a work in two

volumes on animal chemistry, chiefly a compilation, with the exception

of his experiments on the analysis of blood, which constitute an

introduction to the second volume. This book was published in 1806

and 1808. In the year 1806 he and Hisinger began a periodical work,

entitled "Afhandlingar i Fysik, Kemi och Mineralogi," of which six

volumes in all were published, the last in 1818. In this work there

occur forty-seven papers by Berzelius, some of them of great length

and importance, which will be noticed afterwards; but by far the

greatest part of them consist of mineral analyses. We have the analysis

of cerium by Hisinger and Berzelius, together with an account of

the chemical characters of the two oxides of cerium. In the fourth

volume he gives us a new chemical arrangement of minerals, founded

on the supposition that they are all chemical compounds in definite

proportions. Mr. Smithson had thrown out the opinion that _silica_

is an acid: which opinion was taken up by Berzelius, who showed, by

decisive experiments, that it enters into definite combinations

with most of the bases. This happy idea enabled him to show, that

most of the stony minerals are definite compounds of silica, with

certain earths or metallic oxides. This system has undergone several

modifications since he first gave it to the world; and I think it

more than doubtful whether his last co but he has taken care to have

translations of them inserted into Poggensdorf's Annalen, and the

Annales de Chimie et de Physique.

In the Stockholm Memoirs, for 1819, we have his analysis of wavellite,

showing that this mineral is a hydrous phosphate of alumina. The

same analysis and discovery had been made by Fuchs, who published

his results in 1818; but probably Berzelius had not seen the paper;

at least he takes no notice of it. We have also in the same volume

his analysis of euclase, of silicate of zinc, and his paper on the

prussiates.

In the Memoirs for 1820 we have, besides three others, his paper on

the mode of analyzing the ores of nickel. In the Memoirs for 1821 we

have his paper on the alkaline sulphurets, and his analysis of achmite.

The specimen selected for this analysis was probably impure; for two

successive analyses of it, made in my laboratory by Captain Lehunt,

gave a considerable difference in the proportion of the constituents,

and a different formula for the composition than that resulting from

the constituents found by Berzelius.

In the Memoirs for 1822 we have his analysis of the mineral waters

of Carlsbad. In 1823 he published his experiments on uranium, which

were meant as a confirmation and extension of the examination of this

substance previously made by Arfvedson. In the same year appeared his

experiments on fluoric acid and its combinations, constituting one of

the most curious and important of all the numerous additions which

he has made to analytical chemistry. In 1824 we have his analysis of

phosphate of yttria, a mineral found in Norway; of polymignite, a

mineral from the neighbourhood of Christiania, where it occurs in the

zircon sienite, and remarkable for the great number of bases which it

contains united to titanic acid; namely, zirconia, oxide of iron,

lime, oxide of manganese, oxide of cerium, and yttria. We have also

his analysis of arseniate of iron, from Brazil and from Cornwall; and

of chabasite from Ferro. In this last analysis he mentions chabasites

from Scotland, containing soda instead of lime. The only chabasites in

Scotland, that I know of, occur in the neighbourhood of Glasgow; and

in none of these have I found any soda. But I have found soda instead

of lime in chabasites from the north of Ireland, always crystallized

in the form to which Hauy has given the name of _trirhomboidale_. I

think, therefore, that the chabasites analyzed by Arfvedson, to which

Berzelius refers, must have been from Ireland, and not from Scotland;

and I think it may be a question whether this form of crystal, if it

should always be found to contain soda instead of lime, ought not to

constitute a peculiar species.

In 1826 we have his very elaborate and valuable paper on sulphur salts.

In this paper he shows that sulphur is capable of combining with

bodies, in the same way as oxygen, and of converting the acidifiable

bases into acids, and the alkalifiable bases into alkalies. These

sulphur acids and alkalies unite with each other, and form a new class

of saline bodies, which may be distinguished by the name of _sulphur

salts_. This subject has been since carried a good deal further by

M. H. Rose, who has by means of it thrown much light on some mineral

species hitherto quite inexplicable. Thus, what is called _nickel

glance_, is a sulphur salt of nickel. The acid is a compound of sulphur

and arsenic, the base a compound of sulphur and nickel. Its composition

may be represented thus:

1 atom disulphide of arsenic

1 atom disulphide of nickel.

In like manner glance cobalt is

1 atom disulphide of arsenic

1 atom disulphide of nickel.

Zinkenite is composed of

3 atoms sulphide of antimony

1 atom sulphide of lead;

and jamesonite of

2½ atoms sulphide of antimony

1 atom sulphide of lead.

Feather ore of antimony, hitherto confounded with sulphuret of

antimony, is a compound of

5 atoms sulphide of antimony

3 atoms sulphide of lead.

Gray copper ore, which has hitherto appeared so difficult to be reduced

to any thing like regularity, is composed of

1 atom sulphide of antimony or arsenic

2 atoms sulphide of copper or silver.

Dark red silver ore is composed of

1 atom sulphide of antimony

1 atom sulphide of silver;

and light red silver ore of

2 atoms sesquisulphide of arsenic

3 atoms sulphide of silver.

These specimens show how much light the doctrine of sulphur salts has

thrown on the mineral kingdom.

In 1828 he published his experimental investigation of the characters

and compounds of palladium, rhodium, osmium, and iridium; and upon the

mode of analyzing the different ores of platinum.

One of the greatest improvements which Berzelius has introduced into

analytical chemistry, is his mode of separating those bodies which

become acid when united to oxygen, as sulphur, selenium, arsenic, &c.,

from those that become alkaline, as copper, lead, silver, &c. His

method is to put the alloy or ore to be analyzed into a glass tube,

and to pass over it a current of dry chlorine gas, while the powder in

the tube is heated by a lamp. The acidifiable bodies are volatile, and

pass over along the tube into a vessel of water placed to receive them,

while the alkalifiable bodies remain fixed in the tube. This mode of

analysis has been considerably improved by Rose, who availed himself of

it in his analysis of gray copper ore, and other similar compounds.

Analytical chemistry lies under obligations to Berzelius, not merely

for what he has done himself, but for what has been done by those

pupils who were educated in his laboratory. Bonsdorf, Nordenskiöld,

C. G. Gmelin, Rose, Wöhler, Arfvedson, have given us some of the

finest examples of analytical investigations with which the science is

furnished.

P. A. Von Bonsdorf was a professor of Abo, and after that university

was burnt down, he moved to the new locality in which it was planted by

the Russian government. His analysis of the minerals which crystallize

in the form of the amphibole, constitutes a model for the young

analysts to study, whether we consider the precision of the analyses,

or the methods by which the different constituents were separated and

estimated. His analysis of red silver ore first demonstrated that

the metals in it were not in the state of oxides. The nature of the

combination was first completely explained by Rose, after Berzelius's

paper on the sulphur salts had made its appearance. His paper on the

acid properties of several of the chlorides, has served considerably to

extend and to rectify the views first proposed by Berzelius respecting

the different classes of salts.

Nils Nordenskiöld is superintendent of the mines in Finland: his

"Bidrag till närmare kännedom af Finland's Mineralier och Geognosie"

was published in 1820. It contains a description and analysis of

fourteen species of Lapland minerals, several of them new, and all

of them interesting. The analyses were conducted in Berzelius's

laboratory, and are excellent. In 1827 he published a tabular view

of the mineral species, arranged chemically, in which he gives the

crystalline form, hardness, and specific gravity, together with the

chemical formulas for the composition.

C. G. Gmelin is professor of chemistry at Tubingen; he has devoted

the whole of his attention to chemical analysis, and has published a

great number of excellent ones, particularly in Schweigger's Journal.

His analysis of helvine, and of the tourmalin, may be specified as

particularly valuable. In this last mineral, he demonstrated the

presence of boracic acid. Leopold Gmelin, professor of chemistry at

Heidelberg, has also distinguished himself as an analytical chemist.

His System of Chemistry, which is at present publishing, promises to be

the best and most perfect which Germany has produced.

Henry Rose, of Berlin, is the son of that M. Rose who was educated by

Klaproth, and afterwards became the intimate friend and fellow-labourer

of that illustrious chemist. He has devoted himself to analytical

chemistry with indefatigable zeal, and has favoured us with a

prodigious number of new and admirably-conducted analyses. His

analyses of pyroxenes, of the ores of titanium, of gray copper ore,

of silver glance, of red silver ore, miargyrite, polybasite, &c., may

be mentioned as examples. In 1829 he published a volume on analytical

chemistry, which is by far the most complete and valuable work of the

kind that has hitherto appeared; and ought to be carefully studied by

all those who wish to make themselves masters of the difficult, but

necessary art of analyzing compound bodies.[6]

[6] An excellent English translation of this book with several

important additions by the author, has just been published by Mr.

Griffin.

Wöhler is professor of chemistry in the Polytechnic School of Berlin;

he does not appear to have turned his attention to analytical

chemistry, but rather towards extending our knowledge of the compounds

which the different simple bodies are capable of forming with each

other. His discovery of cyanic acid may be mentioned as a specimen. He

is active and young; much, therefore, may be expected from him.

Augustus Arfvedson has distinguished himself by the discovery of the

new fixed alkali, lithia, in petalite and spodumene. It has been lately

ascertained at Moscow, by M. R. Hermann, and the experiments have been

repeated and confirmed by Berzelius, that lithia is a much lighter

substance than it was found to be by Arfvedson, its atomic weight being

only 1·75. We have from Arfvedson an important set of experiments on

uranium and its oxides, and on the action of hydrogen on the metallic

sulphurets. He has likewise analyzed a considerable number of minerals

with great care; but of late years he seems to have lost his activity.

His analysis of chrysoberyl does not possess the accuracy of the rest:

by some inadvertence, he has taken a compound of glucina and alumina

for silica.

I ought to have included Walmstedt and Trollé-Wachmeister among

the Swedish chemists who have contributed important papers towards

the progress of analytical chemistry, the memoir of the former on

chrysolite, and of the latter on the garnets, being peculiarly

valuable. But it would extend this work to an almost interminable

length, if I were to particularize every meritorious experimenter. This

must plead my excuse for having omitted the names of Bucholz, Gehlen,

Fuchs, Dumesnil, Dobereiner, Kupfer, and various other meritorious

chemists who have contributed so much to the perfecting of the

chemical analysis of the mineral kingdom. But it would be unpardonable

to leave out the name of M. Mitcherlich, professor of chemistry in

Berlin, and successor of Klaproth, who was also a pupil of Berzelius.

He has opened a new branch of chemistry to our consideration. His

papers on isomorphous bodies, on the crystalline forms of various sets

of salts, on the artificial formation of various minerals, do him

immortal honour, and will hand him down to posterity as a fit successor

of his illustrious predecessors in the chemical chair of Berlin--a city

in which an uninterrupted series of first-rate chemists have followed

each other for more than a century; and where, thanks to the fostering

care of the Prussian government, the number was never greater than at

the present moment.

The most eminent analytical chemists at present in France are, Laugier,

a nephew and successor of Fourcroy, as professor of chemistry in the

Jardin du Roi, and Berthier, who has long had the superintendence of

the laboratory of the School of Mines. Laugier has not published many

analyses to the world, but those with which he has favoured us appear

to have been made with great care, and are in general very accurate.

Berthier is a much more active man; and has not merely given us many

analyses, but has made various important improvements in the analytical

processes. His mode of separating arsenic acid, and determining its

weight, is now generally followed; and I can state from experience

that his method of fusing minerals with oxide of lead, when the object

is to detect an alkali, is both accurate and easy. Berthier is young,

and active, and zealous; we may therefore expect a great deal from him

hereafter.

The chemists in great Britain have never hitherto distinguished

themselves much in analytical chemistry. This I conceive is owing

to the mode of education which has been hitherto unhappily followed.

Till within these very few years, practical chemistry has been

nowhere taught. The consequence has been, that every chemist must

discover processes for himself; and a long time elapses before he

acquires the requisite dexterity and skill. About the beginning of the

present century, Dr. Kennedy, of Edinburgh, was an enthusiastic and

dexterous analyst; but unfortunately he was lost to the science by a

premature death, after giving a very few, but these masterly, analyses

to the public. About the same time, Charles Hatchett, Esq., was an

active chemist, and published not a few very excellent analyses; but

unfortunately this most amiable and accomplished man has been lost

to science for more than a quarter of a century; the baneful effects

of wealth, and the cares of a lucrative and extensive business,

having completely weaned him from scientific pursuits. Mr. Gregor,

of Cornwall, was an accurate man, and attended only to analytical

chemistry: his analyses were not numerous, but they were in general

excellent. Unfortunately the science was deprived of his services by

a premature death. The same observation applies equally to Mr. Edward

Howard, whose analyses of meteoric stones form an era in this branch of

chemistry. He was not only a skilful chemist, but was possessed of a

persevering industry which peculiarly fitted him for making a figure as

a practical chemist. Of modern British analytical chemists, undoubtedly

the first is Mr. Richard Philips; to whom we are indebted for not

a few analyses, conducted with great chemical skill, and performed

with great accuracy. Unfortunately, of late years he has done little,

having been withdrawn from science by the necessity of providing for

a large family, which can hardly be done, in this country, except

by turning one's attention to trade or manufactures. The same remark

applies to Dr. Henry, who has contributed so much to our knowledge of

gaseous bodies, and whose analytical skill, had it been wholly devoted

to scientific investigations, would have raised his reputation, as a

discoverer, much higher than it has attained; although the celebrity

of Dr. Henry, even under the disadvantages of being a manufacturing

chemist, is deservedly very high. Of the young chemists who have but

recently started in the path of analytical investigation, we expect the

most from Dr. Turner, of the London University. His analyses of the

ores of manganese are admirable specimens of skill and accuracy, and

have completely elucidated a branch of mineralogy which, before his

experiments, and the descriptions of Haidinger appeared, was buried in

impenetrable darkness.

No man that Great Britain has produced was better fitted to have

figured as an analytical chemist, both by his uncommon chemical skill,

and the powers of his mind, which were of the highest order, than

Mr. Smithson Tennant, had he not been in some measure prevented by a

delicate frame of body, which produced in him a state of indolence

somewhat similar to that of Dr. Black. His discovery of osmium and

iridium, and his analysis of emery and magnesian limestone, may

be mentioned as proofs of what he could have accomplished had his

health allowed him a greater degree of exertion. His experiments on

the diamond first demonstrated that it was composed of pure carbon;

while his discovery of phosphuret of lime has furnished lecturers

on chemistry with one of the most brilliant and beautiful of those

exhibitions which they are in the habit of making to attract the

attention of their students.

Smithson Tennant was the only child of the Rev. Calvert Tennant,

youngest son of a respectable family in Wensleydale, near Richmond, in

Yorkshire, and vicar of Selby in that county. He was born on the 30th

of November, 1761: he had the misfortune to lose his father when he was

only nine years of age; and before he attained the age of manhood he

was deprived likewise of his mother, by a very unfortunate accident:

she was thrown from her horse while riding with her son, and killed on

the spot. His education, after his father's death, was irregular, and

apparently neglected; he was sent successively to different schools in

Yorkshire, at Scorton, Tadcaster, and Beverley. He gave many proofs

while young of a particular turn for chemistry and natural philosophy,

both by reading all books of that description which fell in his way,

and by making various little experiments which the perusal of these

books suggested. His first experiment was made at nine years of age,

when he prepared a quantity of gunpowder for fireworks, according to

directions contained in some scientific book to which he had access.

In the choice of a profession, his attention was naturally directed

towards medicine, as being more nearly allied to his philosophical

pursuits. He went accordingly to Edinburgh, about the year 1781, where

he laid the foundation of his chemical knowledge under Dr. Black. In

1782 he was entered a member of Christ's College, Cambridge, where he

began, from that time, to reside. He was first entered as a pensioner;

but disliking the ordinary discipline and routine of an academical

life, he obtained an exemption from those restraints, by becoming a

fellow commoner. During his residence at Cambridge his chief attention

was bestowed on chemistry and botany; though he made himself also

acquainted with the elementary parts of mathematics, and had mastered

the most important parts of Newton's Principia.

In 1784 he travelled into Denmark and Sweden, chiefly with the view of

becoming personally acquainted with Scheele, for whom he had imbibed

a high admiration. He was much gratified by what he saw of this

extraordinary man, and was particularly struck with the simplicity of

the apparatus with which his great experiments had been performed. On

his return to England he took great pleasure in showing his friends at

Cambridge various mineralogical specimens, which had been presented to

him by Scheele, and in exhibiting several interesting experiments which

he had learned from that great chemist. A year or two afterwards he

went to France, to become personally acquainted with the most eminent

of the French chemists. Thence he went to Holland and the Netherlands,

at that time in a state of insurrection against Joseph II.

In 1786 he left Christ's College along with Professor Hermann, and

removed with him to Emmanuel College. In 1788 he took his first degree

as bachelor of physic, and soon after quitted Cambridge and came to

reside in London. In 1791 he made his celebrated analysis of carbonic

acid, which fully confirmed the opinions previously stated by Lavoisier

respecting the constituents of this substance. His mode was to pass

phosphorus through red-hot carbonate of lime. The phosphorus was

acidified, and charcoal deposited. It was during these experiments that

he discovered phosphuret of lime.

In 1792 he again visited Paris; but, from circumstances, being afraid

of a convulsion, he was fortunate enough to leave that city the day

before the memorable 10th of August. He travelled through Italy, and

then passed through part of Germany. On his return to Paris, in

the beginning of 1793, he was deeply impressed with the gloom and

desolation arising from the system of terror then beginning to prevail

in that capital. On calling at the house of M. Delametherie, of whose

simplicity and moderation he had a high opinion, he found the doors

and windows closed, as if the owner were absent. Being at length

admitted, he found his friend sitting in a back room, by candle-light,

with the shutters closed in the middle of the day. On his departure,

after a hurried and anxious conversation, his friend conjured him not

to come again, as the knowledge of his being there might be attended

with serious consequences to them both. To the honour of Delametherie,

it deserves to be stated, that through all the inquisitions of the

revolution, he preserved for his friend property of considerable value,

which Mr. Tennant had intrusted to his care.

On his return from the continent, he took lodgings in the Temple,

where he continued to reside during the rest of his life. He still

continued the study of medicine, and attended the hospitals, but became

more indifferent about entering into practice. He took, however, a

doctor's degree at Cambridge in 1796; but resolved, as his fortune

was independent, to relinquish all idea of practice, as not likely

to contribute to his happiness. Exquisite sensibility was a striking

feature in his character, and it would, as he very properly conceived,

have made him peculiarly unfit for the exercise of the medical

profession. It may be worth while to relate an example of his practical

benevolence which happened about this time.

He had a steward in the country, in whom he had long placed implicit

confidence, and who was considerably indebted to him. In consequence

of this man's becoming embarrassed in his circumstances, Mr. Tennant

went into the country to examine his accounts. A time and place were

appointed for him to produce his books, and show the extent of the

deficiency; but the unfortunate steward felt himself unequal to the

task of such an explanation, and in a fit of despair put an end to

his existence. Touched by this melancholy event, Mr. Tennant used his

utmost exertions for the relief and protection of the family whom

he had left, and not only forgave them the debt, but afforded them

pecuniary assistance, and continued ever afterwards to be their friend

and benefactor.

During the year 1796 he made his experiments to prove that the diamond

is pure carbon. His method was to heat it in a gold tube, with

saltpetre. The diamond was converted into carbonic acid gas, which

combined with the potash from the saltpetre, and by the evolution of

which the quantity of carbon, in a given weight of diamond, might be

estimated. A characteristic trait of Mr. Tennant occurred during the

course of this experiment, which I relate on the authority of Dr.

Wollaston, who was present as an assistant, and who related the fact to

me. Mr. Tennant was in the habit of taking a ride on horseback every

day at a certain hour. The tube containing the diamond and saltpetre

were actually heating, and the experiment considerably advanced, when,

suddenly recollecting that his hour for riding was come, he left the

completion of the process to Dr. Wollaston, and went out as usual to

take his ride.

In the year 1797, in consequence of a visit to a friend in

Lincolnshire, where he witnessed the activity with which improvements

in farming operations were at that time going on, he was induced to

purchase some land in that country, in order to commence farming

operations. In 1799 he bought a considerable tract of waste land in

Somersetshire, near the village of Cheddar, where he built a small

house, in which, during the remainder of his life, he was in the habit

of spending some months every summer, besides occasional visits at

other times of the year. These farming speculations, as might have

been anticipated from the indolent and careless habits of Mr. Tennant,

were not very successful. Yet it appears from the papers which he left

behind him, that he paid considerable attention to agriculture, that he

had read the best books on the subject, and collected many facts on it

during his different journeys through various parts of England. In the

course of these inquiries he had discovered that there were two kinds

of limestone known in the midland counties of England, one of which

yielded a lime injurious to vegetation. He showed, in 1799, that the

presence of carbonate of magnesia is the cause of the bad qualities of

this latter kind of limestone. He found that the magnesian limestone

forms an extensive stratum in the midland counties, and that it occurs

also in primitive districts under the name of dolomite.

He infers from the slow solubility of this limestone in acids, that

it is a double salt composed of carbonate of lime and carbonate of

magnesia in chemical combination. He found that grain would scarcely

germinate, and that it soon perished in moistened carbonate of

magnesia: hence he concluded that magnesia is really injurious to

vegetation. Upon this principle he accounted for the injurious effects

of the magnesian limestone when employed as a manure.

In 1802 he showed that emery is merely a variety of corundum, or of the

precious stone known by the name of sapphire.

During the same year, while endeavouring to make an alloy of lead

with the powder which remains after treating crude platinum with

aqua regia, he observed remarkable properties in this powder, and

found that it contained a new metal. While he was engaged in the

investigation, Descotils had turned his attention to the same powder,

and had discovered that it contained a metal which gives a red colour

to the ammoniacal precipitate of platinum. Soon after, Vauquelin,

having treated the powder with alkali, obtained a volatile metallic

oxide, which he considered as the same metal that had been observed by

Descotils. In 1804 Mr. Tennant showed that this powder contains two new

metals, to which he gave the name of _osmium_ and _iridium_.

Mr. Tennant's health, by this time, had become delicate, and he seldom

went to bed without a certain quantity of fever, which often obliged

him to get up during the night and expose himself to the cold air. To

keep himself in any degree in health, he found it necessary to take a

great deal of exercise on horseback. He was always an awkward and a bad

horseman, so that those rides were sometimes a little hazardous; and

I have more than once heard him say, that a fall from his horse would

some day prove fatal to him. In 1809 he was thrown from his horse near

Brighton, and had his collar-bone broken.

In the year 1812 he was prevailed upon to deliver a few lectures on

the principles of mineralogy, to a number of his friends, among whom

were many ladies, and a considerable number of men of science and

information. These lectures were completely successful, and raised his

reputation very much among his friends as a lecturer. He particularly

excelled in the investigation of minerals by the blowpipe; and I have

heard him repeatedly say, that he was indebted for the first knowledge

of the mode of using that valuable instrument to Assessor Gahn Fahlun.

In 1813, a vacancy occurring in the chemical professorship at

Cambridge, he was solicited to become a candidate. His friends exerted

themselves in his favour with unexampled energy; and all opposition

being withdrawn, he was elected professor in May, 1813.

After the general pacification in 1814 he went to France, and repaired

to the southern provinces of that kingdom. He visited Lyons, Nismes,

Avignon, Marseilles, and Montpellier. He returned to Paris in November,

much gratified by his southern tour. He was to have returned to

England about the latter end of the year; but he continued to linger

on till the February following. On the 15th of that month he went to

Calais; but the wind blew directly into Calais harbour, and continued

unfavourable for several days. After waiting till the 20th he went to

Boulogne, in order to take the chance of a better passage from that

port. He embarked on board a vessel on the 22d, but the wind was still

adverse, and blew so violently that the vessel was obliged to put

back. When Mr. Tennant came ashore, he said that "it was in vain to

struggle with the elements, and that he was not yet tired of life."

It was determined, in case the wind should abate, to make another

trial in the evening. During the interval Mr. Tennant proposed to his

fellow-traveller, Baron Bulow, that they should hire horses and take

a ride. They rode at first along the sea-side; but, on Mr. Tennant's

suggestion, they went afterwards to Bonaparte's pillar, which stands on

an eminence about a league from the sea-shore, and which, having been

to see it the day before, he was desirous of showing to Baron Bulow.

On their return from thence they deviated a little from the road, in

order to look at a small fort near the pillar, the entrance to which

was over a fosse twenty feet deep. On the side towards them, there

was a standing bridge for some way, till it joined a drawbridge, which

turned on a pivot. The end next the fort rested on the ground. On the

side next to them it was usually fastened by a bolt; but the bolt had

been stolen about a fortnight before, and was not replaced. As the

bridge was too narrow for them to go abreast, the baron said he would

go first, and attempted to ride over it; but perceiving that it was

beginning to sink, he made an effort to pass the centre, and called out

to warn his companion of his danger; but it was too late: they were

both precipitated into the trench. The baron, though much stunned,

fortunately escaped without any serious hurt; but on recovering his

senses, and looking round for Mr. Tennant, he found him lying under his

horse nearly lifeless. He was taken, however, to the Civil Hospital,

as the nearest place ready to receive him. After a short interval, he

seemed in some slight degree to recover his senses, and made an effort

to speak, but without effect, and died within the hour. His remains

were interred a few days after in the public cemetery at Boulogne,

being attended to the grave by most of the English residents.

There is another branch of investigation intimately connected with

analytical chemistry, the improvements in which have been attended

with great advantage, both to mineralogists and chemists. I mean the

use of the blowpipe, to make a kind of miniature analysis of minerals

in the dry way; so far, at least, as to determine the nature of the

constituents of the mineral under examination. This is attended with

many advantages, as a preliminary to a rigid analysis by solution. By

informing us of the nature of the constituents, it enables us to form

a plan of the analysis beforehand, which, in many cases, saves the

trouble and the tediousness of two separate analytical investigations;

for when we set about analyzing a mineral, of the nature of which we

are entirely ignorant, two separate sets of experiments are in most

cases indispensable. We must examine the mineral, in the first place,

to determine the nature of its constituents. These being known, we

can form a plan of an analysis, by means of which we can separate and

estimate in succession the amount of each constituent of the mineral.

Now a judicious use of the blowpipe often enables us to determine the

nature of the constituents in a few minutes, and thus saves the trouble

of the preliminary analysis.

The blowpipe is a tube employed by goldsmiths in soldering. By means

of it, they force the flame of a candle or lamp against any particular

point which they wish to heat. This enables them to solder trinkets

of various kinds, without affecting any other part except the portion

which is required to be heated. Cronstedt and Engestroem first thought

of applying this little instrument to the examination of minerals. A

small fragment of the mineral to be examined, not nearly so large as

the head of a small pin, was put upon a piece of charcoal, and the

flame of a candle was made to play upon it by means of a blowpipe, so

as to raise it to a white heat. They observed whether it decrepitated,

or was dissipated, or melted; and whatever the effect produced was,

they were enabled from it to draw consequences respecting the nature of

the mineral under examination.

The importance of this instrument struck Bergman, and induced him

to wish for a complete examination of the action of the heat of the

blowpipe upon all different minerals, either tried _per se_ upon

charcoal, or mixed with various fluxes; for three different substances

had been chosen as fluxes, namely, _carbonate of soda_, _borax_, and

_biphosphate of soda_; or, at least, what was in fact an equivalent

for this last substance, _ammonio-phosphate of soda_, or _microcosmic

salt_, at that time extracted from urine. This salt is a compound

of one integrant particle of phosphate of soda, and one integrant

particle of phosphate of ammonia. When heated before the blowpipe it

fuses, and the water of crystallization, together with the ammonia, are

gradually dissipated, so that at last nothing remains but biphosphate

of soda. These fluxes have been found to act with considerable energy

on most minerals. The carbonate of soda readily fuses with those that

contain much silica, while the borax and biphosphate of soda act most

powerfully on the bases, not sensibly affecting the silica, which

remains unaltered in the fused bead. A mixture of borax and carbonate

of soda upon charcoal in general enables us to reduce the metallic

oxides to the state of metals, provided we understand the way of

applying the flame properly. Bergman employed Gahn, who was at that

time his pupil, and whose skill he was well acquainted with, to make

the requisite experiments. The result of these experiments was drawn

up into a paper, which Bergman sent to Baron Born in 1777, and they

were published by him at Vienna in 1779. This valuable publication

threw a new light upon the application of the blowpipe to the assaying

of minerals; and for every thing new which it contained Bergman was

indebted to Gahn, who had made the experiments.

John Gottlieb Gahn, the intimate friend of Bergman and of Scheele,

was one of the best-informed men, and one whose manners were the most

simple, unaffected, and pleasing, of all the men of science with whom I

ever came in contact. I spent a few days with him at Fahlun, in 1812,

and they were some of the most delightful days that I ever passed in my

life. His fund of information was inexhaustible, and was only excelled

by the charming simplicity of his manners, and by the benevolence and

goodness of heart which beamed in his countenance. He was born on the

17th of August, 1745, at the Woxna iron-works, in South Helsingland,

where his father, Hans Jacob Gahn, was treasurer to the government

of Stora Kopperberg. His grandfather, or great-grandfather, he told

me, had emigrated from Scotland; and he mentioned several families in

Scotland to which he was related. After completing his school education

at Westeräs, he went, in the year 1760, to the University of Upsala.

He had already shown a decided bias towards the study of chemistry,

mineralogy, and natural philosophy; and, like most men of science in

Sweden, where philosophical instrument-makers are scarcely to be found,

he had accustomed himself to handle the different tools, and to supply

himself in that manner with all the different pieces of apparatus which

he required for his investigations. He seems to have spent nearly

ten years at Upsala, during which time he acquired a very profound

knowledge in chemistry, and made various important discoveries, which

his modesty or his indifference to fame made him allow others to pass

as their own. The discovery of the rhomboidal nucleus of carbonate of

lime in a six-sided prism of that mineral, which he let fall, and which

was accidentally broken, constitutes the foundation of Hauy's system of

crystallization. He communicated the fact to Bergman, who published it

as his own in the second volume of his Opuscula, without any mention of

Gahn's name.

The earth of bones had been considered as a peculiar simple earth; but

Gahn ascertained, by analysis, that it was a compound of phosphoric

acid and lime; and this discovery he communicated to Scheele, who,

in his paper on fluor spar, published in 1771, observed, in the

seventeenth section, in which he is describing the effect of phosphoric

acid on fluor spar, "It has lately been discovered that the earth of

bones, or of horns, is calcareous earth combined with phosphoric acid."

In consequence of this remark, in which the name of Gahn does not

appear, it was long supposed that Scheele, and not Gahn, was the author

of this important discovery.

It was during this period that he demonstrated the metallic nature of

manganese, and examined the properties of the metal. This discovery was

announced as his, at the time, by Bergman, and was almost the only one

of the immense number of new facts which he had ascertained that was

publicly known to be his.

On the death of his father he was left in rather narrow circumstances,

which obliged him to turn his immediate attention to mining and

metallurgy. To acquire a practical knowledge of mining he associated

with the common miners, and continued to work like them till he had

acquired all the practical dexterity and knowledge which actual labour

could give. In 1770 he was commissioned by the College of Mines to

institute a course of experiments, with a view to improve the method of

smelting copper, at Fahlun. The consequence of this investigation was a

complete regeneration of the whole system, so as to save a great deal

both of time and fuel.

Sometime after, he became a partner in some extensive works at Stora

Kopperberg, where he settled as a superintendent. From 1770, when he

first settled at Fahlun, down to 1785, he took a deep interest in the

improvement of the chemical works in that place and neighbourhood. He

established manufactories of sulphur, sulphuric acid, and red ochre.

In 1780 the Royal College of Mines, as a testimony of their sense of

the value of Gahn's improvements, presented him with a gold medal of

merit. In 1782 he received a royal patent as mining master. In 1784 he

was appointed assessor in the Royal College of Mines, in which capacity

he officiated as often as his other vocations permitted him to reside

in Stockholm. The same year he married Anna Maria Bergstrom, with whom

he enjoyed for thirty-one years a life of uninterrupted happiness. By

his wife he had a son and two daughters.

In the year 1773 he had been elected chemical stipendiary to the Royal

College of Mines, and he continued to hold this appointment till the

year 1814. During the whole of this period the solution of almost

every difficult problem remitted to the college devolved upon him. In

1795 he was chosen a member of the committee for directing the general

affairs of the kingdom. In 1810 he was made one of the committee for

the general maintenance of the poor. In 1812 he was elected an active

associate of the Royal Academy for Agriculture; and in 1816 he became a

member of the committee for organizing the plan of a Mining Institute.

In 1818 he was chosen a member of the committee of the Mint; but from

this situation he was shortly after, at his own request, permitted to

withdraw.

His wife died in 1815, and from that period his health, which had never

been robust, visibly declined. Nature occasionally made an effort to

shake off the disease; but it constantly returned with increasing

strength, until, in the autumn of 1818, the decay became more rapid in

its progress, and more decided in its character. He became gradually

weaker, and on the 8th of December, 1818, died without a struggle, and

seemingly without pain.

Ever after the experiments on the blowpipe which Gahn performed at

the request of Bergman, his attention had been turned to that piece

of apparatus; and during the course of a long life he had introduced

so many improvements, that he was enabled, by means of the blowpipe,

to determine in a few minutes the constituents of almost any mineral.

He had gone over almost all the mineral kingdom, and determined the

behaviour of almost every mineral before the blowpipe, both by itself

and when mixed with the different fluxes and reagents which he had

invented for the purpose of detecting the different constituents; but,

from his characteristic unwillingness to commit his observations and

experiments to writing, or to draw them up into a regular memoir, had

not Berzelius offered himself as an assistant, they would probably

have been lost. By his means a short treatise on the blowpipe, with

minute directions how to use the different contrivances which he had

invented, was drawn up and inserted in the second volume of Berzelius's

Chemistry. Berzelius and he afterwards examined all the minerals

known, or at least which they could procure, before the blowpipe;

and the result of the whole constituted the materials of Berzelius's

treatise on the blowpipe, which has been translated into German,

French, and English. It may be considered as containing the sum of

all the improvements which Gahn had made on the use of the blowpipe,

together with all the facts that he had collected respecting the

phenomena exhibited by minerals before the blowpipe. It constitutes an

exceedingly useful and valuable book, and ought to make a part of the

library of every analytical chemist.

Dr. Wollaston had paid as much attention to the blowpipe as Gahn, and

had introduced so many improvements into its use, that he was able,

by means of it, to determine the nature of the constituents of any

mineral in the course of a few minutes. He was fond of such analytical

experiments, and was generally applied to by every person who thought

himself possessed of a new mineral, in order to be enabled to state

what its constituents were. The London mineralogists if the race be not

extinct, must sorely feel the want of the man to whom they were in the

habit of applying on all occasions, and to whom they never applied in

vain.

Dr. William Hyde Wollaston, was the son of the Reverend Dr. Wollaston,

a clergyman of some rank in the church of England, and possessed of a

competent fortune. He was a man of abilities, and rather eminent as an

astronomer. His grandfather was the celebrated author of the Religion

of Nature delineated. Dr. William Hyde Wollaston was born about the

year 1767, and was one of fifteen children, who all reached the age of

manhood. His constitution was naturally feeble; but by leading a life

of the strictest sobriety and abstemiousness he kept himself in a state

fit for mental exertion. He was educated at Cambridge, where he was at

one time a fellow. After studying medicine by attending the hospitals

and lectures in London, and taking his degree of doctor at Cambridge,

he settled at Bury St. Edmund's, where he practised as a physician

for some years. He then went to London, became a fellow of the Royal

College of Physicians, and commenced practitioner in the metropolis. A

vacancy occurring in St. George's Hospital, he offered himself for the

place of physician to that institution; but another individual, whom he

considered his inferior in knowledge and science, having been preferred

before him, he threw up the profession of medicine altogether, and

devoted the rest of his life to scientific pursuits. His income, in

consequence of the large family of his father, was of necessity small.

In order to improve it he turned his thoughts to the manufacture of

platinum, in which he succeeded so well, that he must have, by means

of it, realized considerable sums. It was he who first succeeded in

reducing it into ingots in a state of purity and fit for every kind of

use: it was employed, in consequence, for making vessels for chemical

purposes; and it is to its introduction that we are to ascribe the

present accuracy of chemical investigations. It has been gradually

introduced into the sulphuric acid manufactories, as a substitute for

glass retorts.

Dr. Wollaston had a particular turn for contriving pieces of apparatus

for scientific purposes. His reflecting goniometer was a most valuable

present to mineralogists, and it is by its means that crystallography

has acquired the great degree of perfection which it has recently

exhibited. He contrived a very simple apparatus for ascertaining the

power of various bodies to refract light. His camera lucida furnished

those who were ignorant of drawing with a convenient method of

delineating natural objects. His periscopic glasses must have been

found useful, for they sold rather extensively: and his sliding rule

for chemical equivalents furnished a ready method for calculating the

proportions of one substance necessary to decompose a given weight of

another.

Dr. Wollaston's knowledge was more varied, and his taste less exclusive

than any other philosopher of his time, except Mr. Cavendish: but

optics and chemistry are the two sciences which lie under the greatest

obligations to him. His first chemical paper on urinary calculi at once

added a vast deal to what had been previously known. He first pointed

out the constituents of the mulberry calculi, showing them to be

composed of oxalate of lime and animal matter. He first distinguished

the nature of the triple phosphates. It was he who first ascertained

the nature of the cystic oxides, and of the chalk-stones, which appear

occasionally in the joints of gouty patients. To him we owe the first

demonstration of the identity of galvanism and common electricity;

and the first explanation of the cause of the different phenomena

exhibited by galvanic and common electricity. To him we are indebted

for the discovery of palladium and rhodium, and the first account of

the properties and characters of these two metals. He first showed

that oxalic acid and potash unite in three different proportions,

constituting oxalate, binoxalate, and quadroxalate of potash. Many

other chemical facts, first ascertained by him, are to be found in the

numerous papers of his scattered over the last forty volumes of the

Philosophical Transactions: and perhaps not the least valuable of them

is his description of the mode of reducing platinum from the raw state,

and bringing it into the state of an ingot.

Dr. Wollaston died in the month of January, 1829, in consequence of

a tumour formed in the brain, near, if I remember right, the thalami

nervorum opticorum. There is reason to suspect that this tumour had

been some time in forming. He had, without exception, the sharpest

eye that I have ever seen: he could write with a diamond upon glass

in a character so small, that nothing could be distinguished by the

naked eye but a ragged line; yet when the letters were viewed through

a microscope, they were beautifully regular and quite legible. He

retained his senses to almost the last moment of his life: when he lay

apparently senseless, and his friends were anxiously solicitous whether

he still retained his understanding, he informed them, by writing, that

his senses were still perfectly entire. Few individuals ever enjoyed a

greater share of general respect and confidence, or had fewer enemies,

than Dr. Wollaston. He was at first shy and distant, and remarkably

circumspect, but he grew insensibly more and more agreeable as you got

better acquainted with him, till at last you formed for him the most

sincere friendship, and your acquaintance ended in the warmest and

closest attachment.