2. _The Lixiviation._--The lixiviation is best performed in stone-built

cisterns; those of wood, however strong at first, are soon decomposed,

and need repairs. They ought to be erected in the neighbourhood of the

calcining heaps, to save the labour of transport, and so arranged that

the solutions from the higher cisterns may spontaneously flow into the

lower. In this point of view, a sloping terrace is the best situation

for an alum work. In the lowest part of this terrace, and in the

neighbourhood of the boiling-house, there ought to be two or more large

deep tanks, for holding the crude lixivium, and they should be protected

from the rain by a proper shed. Upon a somewhat higher level the

cisterns of the clear lixivium may be placed. Into the highest range of

cisterns the calcined mineral is to be put, taking care to lay the

largest lumps at the bottom, and to cover them with lighter ashes. A

sufficient quantity of water is now to be run over it, and allowed to

rest for some time. The lixivium may then be drawn off, by a stopcock

connected with a pipe at the bottom of the cistern, and run into another

cistern at a somewhat lower level. Fresh water must now be poured on the

partly exhausted schist, and allowed to remain for a sufficient time.

This lixivium, being weak, should be run off into a separate tank. In

some cases a third addition of fresh water may be requisite, and the

weak lixivium which is drawn off may be reserved for a fresh portion of

calcined mineral. In order to save evaporation, it is always requisite

to strengthen weak leys by employing them instead of water for fresh

portions of calcined schist. Upon the ingenious disposition and form of

these lixiviating cisterns much of the economy and success of an alum

work depend. The hydrometer should be always used to determine the

degree of concentration which the solutions acquire.

The lixiviated stone being thus exhausted of its soluble ingredients, is

to be removed from the cisterns, and piled up in a heap in any

convenient place, where it may be left either spontaneously to

decompose, or, after drying, may be subjected to another calcination.

The density of the solution may be brought, upon an average, up to the

sp. gr. of from 1·09 to 1·15. The latter density may always be obtained

by pumping up the weaker solutions upon fresh calcined _mine_. This

strong liquor is then drawn off, when the sulphate of lime, the oxide of

iron, and the earths are deposited. It is of advantage to leave the

liquor exposed for some time, whereby the green vitriol may pass into a

persulphate of iron with the deposition of some oxide, while the

liberated acid may combine with some of the clay present, so as to

increase the quantity of sulphate of alumina. The manufacture of alum is

the more imperfect, as the quantity of sulphate of iron left

undecomposed is greater, and therefore every expedient ought to be tried

to convert the sulphate of iron into sulphate of alumina.

3. _The evaporation of the Schist Lixivium._--As the aluminous liquors,

however well settled at first, are apt, on the great scale, to deposit

earthy matters in the course of their concentration by heat, they are

best evaporated by a surface fire, such as that employed at Hurlett and

Campsie. A water-tight stone cistern must be built, having a layer of

well rammed clay behind the flags or tiles which line its bottom and

sides. This cistern may be 4 or 6 feet wide, 2 or 3 feet deep, and 30 or

40 feet long, and it is covered in by an arch of stone or brickwork. At

one extremity of this tunnel, or covered canal, a fire-grate is set, and

at the other a lofty chimney is erected. The cistern being filled to the

brim with the alum ley, a strong fire is kindled in the reverberatory

grate, and the flame and hot air are forced to sweep along the surface

of the liquor, so as to keep it in constant ebullition, and to carry off

the aqueous parts in vapour. The soot which is condensed in the process

falls to the bottom, and leaves the body of the liquor clear. As the

concentration goes on, more of the rough lixivium is run in from the

settling cistern, placed on a somewhat higher level, till the whole gets

charged with a clear liquor of a specific gravity sufficiently high for

transferring into the proper lead boilers.

At Whitby, the lead pans are 10 feet long, 4 feet 9 inches wide, 2 feet

2 inches deep at the one end, and 2 feet 8 inches deep at the other.

This increase of depth and corresponding slope, facilitates the

decantation of the concentrated lixivium by means of a syphon, applied

at the lower end. The bottom of the pan is supported by a series of

parallel iron bars, placed very near each other. In these lead pans the

liquor is concentrated, at a brisk boiling heat, by means of the flame

of a flue beneath them. Every morning the pans are emptied into a

settling cistern of stone or lead. The specific gravity of the liquor

should be about 1·4 or 1·5, being a saturated solution of the saline

matters present. The proper degree of density must vary, however, with

different kinds of lixivia, and according to the different views of the

manufacturer. For a liquor which consists of two parts of sulphate of

alumina, and one part of sulphate of iron, a specific gravity of 1·25

may be sufficient; but for a solution which contains two parts of

sulphate of iron to one of sulphate of alumina, so that the green

vitriol must be withdrawn first of all by crystallisation, a specific

gravity of 1·4 may be requisite.

The construction of an evaporating furnace well adapted to the

concentration of aluminous and other crude lixivia, is described under

SODA. The liquor basin may be made of tiles or flags puddled in clay,

and secured at the seams with a good _hydraulic_ cement. A mortar made

of quicklime mixed with the exhausted schist in powder, and iron

turnings, is said to answer well for this purpose. Sometimes over the

reverberatory furnace a flat pan is laid, instead of the arched top,

into which the crude liquor is put for neutralisation and partial

concentration. In Germany, such a pan is made of copper, because iron

would waste too fast, and lead would be apt to melt. From this

preparation basin the under evaporating trough is gradually supplied

with hot liquor. At one side of this lower trough, there is sometimes a

door, through which the sediment may be raked out as it accumulates upon

the bottom. Such a contrivance is convenient for this mode of

evaporation, and it permits, also, any repairs to be readily made; but,

indeed, an apparatus of this kind, well mounted at first, will serve for

many years.

In the course of the final concentration of the liquors, it is customary

to add some of the mother waters of a former process, the quantity of

which must be regulated by a proper analysis and knowledge of their

contents. If these mother waters contain much free sulphuric acid, from

the peroxidation of their sulphate of iron, they may prove useful in

dissolving a portion of the alumina of the sediment which is always

present in greater or less quantity.

4. _The precipitation of the Alum by adding Alkaline Salts._--As a

general rule, it is most advantageous to separate, first of all, from

the concentrated clear liquors, the alum in the state of powder or small

crystals, by addition of the proper alkaline matter, and to leave the

mingled foreign salts, such as the sulphate of iron or magnesia, in

solution, instead of trying to abstract these salts by a previous

crystallisation. In this way we not only simplify and accelerate the

manufacture of alum, and leave the mother waters to be worked up at any

convenient season, but we also avoid the risk of withdrawing any of the

sulphate of alumina with the sulphate of iron or magnesia. On this

account, the concentration of the liquor ought not to be pushed so far

as that, when it gets cold, it should throw out crystals, but merely to

the verge of this point. This density may be determined by suitable

experiments.

The clear liquor should now be run off into the precipitation cistern,

and have the proper quantity of sulphate or muriate of potash, or impure

sulphate or carbonate of ammonia added to it. The sulphate of potash,

which is the best precipitant, forms 18·34 parts out of 100 of

crystallised alum; and therefore that quantity of it, or its equivalent

in muriate of potash, or other potash or ammoniacal salts, must be

introduced into the aluminous liquor. Since sulphate of potash takes 10

parts of cold water to dissolve it, but is much more soluble in boiling

water, and since the precipitation of alum is more abundant the more

concentrated the mingled solutions are, it would be prudent to add the

sulphate solution as hot as may be convenient; but, as muriate of potash

is fully three times more soluble in cold water, it is to be preferred

as a precipitant, when it can be procured at a cheap rate. It has, also,

the advantage of decomposing the sulphate of iron present into a

muriate, a salt very difficult of crystallisation, and, therefore, less

apt to contaminate the crystals of alum. The quantity of alkaline salts

requisite to precipitate the alum, in a granular powder, from the

lixivium, depends on their richness in potash or ammonia, on the one

hand, and on the richness of the liquors in sulphate of alumina on the

other; and it must be ascertained, for each large quantity of product,

by a preliminary experiment in a precipitation glass. Here, an aliquot

measure of the aluminous liquor being taken, the liquid precipitant must

be added in successive portions, as long as it causes any cloud, when

the quantity added will be indicated by the graduation of the vessel. A

very exact approximation is not practicable upon the great scale; but,

as the mother waters are afterwards mixed together in one cistern, any

excess of the precipitant, at one time, is corrected by excess of

aluminous sulphate at another, and the resulting alum meal is collected

at the bottom. When the precipitated saline powder is thoroughly settled

and cooled, the supernatant mother water must be drawn off by a pump, or

rather a syphon or stopcock, into a lower cistern. The more completely

this drainage is effected, the more easily and completely will the alum

be purified.

This mother liquor has, generally, a specific gravity of 1·4 at a medium

temperature of the atmosphere, and consists of a saturated solution of

sulphate or muriate of black and red oxide of iron, with sulphate of

magnesia, in certain localities, and muriate of soda, when the soaper’s

salt has been used as a precipitant, as also a saturated solution of

sulphate of alumina. By adding some of it, from time to time, to the

fresh lixivia, a portion of that sulphate is converted into alum; but,

eventually, the mother water must be evaporated, so as to obtain from it

a crop of ferruginous crystals; after which it becomes capable, once

more, of giving up its alum to the alkaline precipitants.

When the aluminous lixivia contain a great deal of sulphate of iron, it

may be good policy to withdraw a portion of it by crystallisation before

precipitating the alum. With this view, the liquors must be evaporated

to the density of 1·4, and then run off into crystallising stone

cisterns. After the green vitriol has concreted, the liquor should be

pumped back into the evaporating pan, and again brought to the density

of 1·4. On adding to it, now, the alkaline precipitants, the alum will

fall down from this concentrated solution, in a very minute crystalline

powder, very easy to wash and purify. But this method requires more

vessels and manipulation than the preceding, and should only be had

recourse to from necessity; since it compels us to carry on the

manufacture of both the valuable alum and the lower priced salts at the

same time; moreover, the copperas extracted at first from the schist

liquors carries with it, as we have said, a portion of the sulphate of

alumina, and acquires thereby a dull aspect; whereas the copperas

obtained after the separation of the alum is of a brilliant appearance.

5. _The washing, or edulcoration, of the Alum Powder._--This crystalline

pulverulent matter has a brownish colour, from the admixture of the

ferruginous liquors; but it may be freed from it by washing with very

cold water, which dissolves not more than one sixteenth of its weight of

alum. After stirring the powder and the water well together, the former

must be allowed to settle, and then the washing must be drawn off. A

second washing will render the alum nearly pure. The less water is

employed, and the more effectually it is drained off, the more complete

is the process. The second water may be used in the first washing of

another portion of alum powder, in the place of pure water. These

washings may be added to the schist lixivia.

6. _The crystallisation._--The washed alum is put into a lead pan, with

just enough water to dissolve it at a boiling heat; fire is applied, and

the solution is promoted by stirring. Whenever it is dissolved in a

saturated state, it is run off into the crystallising vessels, which are

called _roching_ casks. These casks are about five feet high, three feet

wide in the middle, somewhat narrower at the ends; they are made of very

strong staves, nicely fitted to each other, and held together by strong

iron hoops, which are driven on _pro tempore_, so that they may be

easily knocked off again, in order to take the staves asunder. The

concentrated solution, during its slow cooling in these close vessels,

forms large regular crystals, which hang down from the top, and project

from the sides, while a thick layer or cake lines the whole interior of

the cask. At the end of eight or ten days, more or less, according to

the weather, the hoops and staves are removed, when a cask of apparently

solid alum is disclosed to view. The workman now pierces this mass with

a pickaxe at the side near the bottom, and allows the mother water of

the interior to run off on the sloping stone floor into a proper

cistern, whence it is taken and added to another quantity of washed

powder to be crystallised with it. The alum is next broken into lumps,

exposed in a proper place to dry, and is then put into the finished bing

for the market. There is sometimes a little insoluble basic alum

(subsulphate) left at the bottom of the cask. This being mixed with the

former mother liquors, gets sulphuric acid from them; or, being mixed

with a little sulphuric acid, it is equally converted into alum.

When, instead of potash or its salts, the ammoniacal salts are used, or

putrid urine, with the aluminous lixivia, ammoniacal alum is produced,

which is perfectly similar to the potash alum in its appearance and

properties. At a gentle heat both lose their water of crystallisation,

amounting to 45-1/2 per cent. for the potash alum, and 48 for the

ammoniacal. The quantity of acid is the same in both, as, also, very

nearly the quantity of alumina, as the following analyses will show:

Potash alum. Ammonia alum.

Sulphate of potash 18·34 Sulphate of ammonia 12·88

Sulphate of alumina 36·20 Sulphate of alumina 38·64

Water 45·46 Water 48·48

------ ------

100·00 100·00

------ ------

Or otherwise, Potash alum. Ammonia alum.

1 atom sulphate of potash 1089·07 1 atom sulphate of ammonia 716·7

1 alumina 2149·80 1 alumina 2149·8

24 water 2669·52 24 water 2699·5

------- ------

5938·39 5566·0

------- ------

Or, Potash alum. Ammonia alum.

Alumina 10·82 Alumina 11·90

Potash 9·94 Ammonia 3·89

Sulphuric Acid 33·77 Sulphuric acid 36·10

Water 45·47 Water 48·11

------ ------

100·00 100·00

------ ------

When heated pretty strongly, the ammoniacal alum loses its sulphuric

acid and ammonia, and only the earth remains. This is a very convenient

process for procuring pure alumina. Ammoniacal alum is easily

distinguished from the other by the smell of ammonia which it exhales

when triturated with quicklime. The Roman alum, made from alum stone,

possesses most of the properties of the schist-made alums, but it has a

few peculiar characters: it crystallises always in opaque cubes, whereas

the common alum crystallises in transparent octahedrons. It is probable

that Roman alum is a sulphate of alumina and potash, with a slight

excess of the earthy ingredient. It is permanent when dissolved in cold

water; for after a slow evaporation it is recovered in a cubical form.

But when it is dissolved in water heated to 110° Fahr. and upwards, or

when its solution is heated above this pitch, subsulphate of alumina

falls, and on evaporation octahedral crystals of common alum are

obtained. The exact composition of the Roman alum has not been

determined, as far as I know. It probably differs from the other also in

its water of crystallisation. The Roman alum contains, according to MM.

Thenard and Roard, only 1/2200 of sulphate of iron, while the common

commercial alums contain 1/1000. It may be easily purified by solution,

granulation, crystallisation, and washing, as has been already

explained.

Alum is made extensively in France from an artificial sulphate of

alumina. For this purpose clays are chosen as free as possible from

carbonate of lime and oxide of iron. They are calcined in a

reverberatory furnace, in order to expel the water, to peroxidise the

iron, and to render the alumina more easily acted on by the acid. The

expulsion of the water renders the clay porous and capable of absorbing

the sulphuric acid by capillary attraction. The peroxidation of the iron

renders it less soluble in the sulphuric acid; and the silica of the

clay, by reacting on the alumina, impairs its aggregation, and makes it

more readily attracted by the acid. The clay should, therefore, be

moderately calcined; but not so as to indurate it like pottery ware, for

it would then suffer a species of siliceous combination which would make

it resist the action of acids. The clay is usually calcined in a

reverberatory furnace, the flame of which serves thereafter to heat two

evaporating pans and a basin for containing a mixture of the calcined

clay and sulphuric acid. As soon as the clay has become friable in the

furnace it is taken out, reduced to powder, and passed through a fine

sieve. With 100 parts of the pulverised clay, 45 parts of sulphuric

acid, of sp. gr. 1·45, are well mixed, in a stone basin, arched over

with brickwork. The flame and hot air of a reverberatory furnace are

made to play along the mixture, in the same way as described for

evaporating the schist liquors. See SODA. The mixture, being stirred

from time to time, is, at the end of a few days, to be raked out, and to

be set aside in a warm place, for the acid to work on the clay, during

six or eight weeks. At the end of this time it must be washed, to

extract the sulphate of alumina. With this view, it may be treated like

the roasted alum ores above described. If potash alum is to be formed,

this sulphate of alumina is evaporated to the specific gravity of 1·38;

but if ammonia alum, to the specific gravity of only 1·24; because the

sulphate of ammonia, being soluble in twice its weight of water, will

cause a precipitation of pulverulent alum from a weaker solution of

sulphate of alumina than the less soluble sulphate of potash could do.

The alum stone, from which the Roman alum is made, contains potash. The

following analysis of _alunite_, by M. Cordier, places this fact in a

clear light:--

Sulphate of potash 18·53

Sulphate of alumina 38·50

Hydrate of alumina 42·97

------

100·00

------

To transform this compound into alum, it is merely necessary to abstract

the hydrate of alumina. The ordinary alum stone, however, is rarely so

pure as the above analysis would seem to show; for it contains a mixture

of other substances; and the above are in different proportions.

Alum is very extensively employed in the arts, most particularly in

dyeing, lake making, dressing sheep-skins, pasting paper, in clarifying

liquors, &c. Its purity for the dyer may be tested by prussiate of

potash, which will give solution of alum a blue tint in a few minutes if

it contain even a very minute portion of iron. A bit of nut-gall is also

a good test of iron.

AMADOU. The French name of the spongy combustible substance, called in

German _zunderschwamm_, prepared from a species of agaric, the _boletus

igniarius_, a kind of mushroom, which grows on the trunks of old oaks,

ashes, beeches, &c. It must be plucked in the months of August and

September. It is prepared by removing the outer bark with a knife, and

separating carefully the spongy substance of a yellow brown colour,

which lies within it, from the ligneous matter below. This substance is

cut into thin slices, and beat with a mallet to soften it, till it can

be easily pulled asunder between the fingers. In this state the

_boletus_ is a valuable substance for stopping oozing hemorrhages, and

some other surgical purposes. To convert it into tinder it must receive

a finishing preparation, which consists in boiling it in a strong

solution of nitre; drying it, beating it anew, and putting it a second

time into the solution. Sometimes, indeed, to render it very

inflammable, it is imbued with gunpowder, whence the distinction of

black and brown amadou.

All the puff balls of the lycopodium genus of plants, which have a

fleshy or filamentous structure, yield a tinder quite ready for soaking

in gunpowder water. The Hindoos employ a leguminous plant, which they

call _solu_, for the same purpose. Its thick spongy stem, being reduced

to charcoal, takes fire like amadou.

AMALGAM. When mercury is alloyed with any metal, the compound is called

an amalgam of that metal; as, for example, an amalgam of tin, bismuth,

&c.

AMALGAMATION. This is a process used extensively in extracting silver

and gold from certain of their ores, founded on the property which

mercury has to dissolve these metals as disseminated in the minerals,

and thus to separate them from the earthy matters. See MERCURY,

METALLURGY, and SILVER.

AMBER. (_Succin_, Fr.; _Bernstein_, Germ.) A mineral solid, of a yellow

colour of various shades, which burns quite away with flame, and

consists of carbon, hydrogen, and oxygen, in nearly the same

proportions, and the same state of combination, as vegetable resin. Its

specific gravity varies, by my trials, from 1·080 to 1·085. It becomes

negatively and powerfully electrical by friction. When applied to a

lighted candle it takes fire, swells considerably, and exhales a white

smoke of a pungent odour; but does not run into drops. Copal, which

resembles it in several respects, differs in being softer, and in

melting into drops at the flame; and mellite, or honey-stone, which is a

mineral of a similar colour, becomes white when laid on a red-hot coal.

The texture of amber is resino-vitreous, its fracture conchoidal, and

lustre glassy. It is perfectly homogeneous; sufficiently hard to scratch

gypsum, and to take a fine polish. It is, however, scratched by

calcareous spar. When amber is distilled in a retort, crystalline

needles of succinic acid sublime into the dome, and oil of amber drops

from the beak into the receiver. Fossil resins, such as that of

Highgate, found in the London clay formation, do not afford succinic

acid by heat; nor does copal. Amber is occasionally found of a whitish

and brownish colour.

The most interesting fact relative to this vegeto-mineral is its

geological position, which is very characteristic and well determined.

It is found almost uniformly in separate nodules, disseminated in the

sand, clay, or fragments of lignite of the plastic clay, and lignite

formation, situated between the _calcaire grossier_ (crag limestone) of

the tertiary strata above, and the white chalk below. The size of these

nodules varies from a nut to a man’s head; but this magnitude is very

rare in true amber. It does not occur either in continuous beds, like

the chalk flints, nor in veins; but it lies at one time in the earthy or

friable strata, which accompany or include the lignites; at another,

entangled in the lignites themselves; and is associated with the

minerals which constitute this formation, principally the pyrites, the

most abundant of all. The pieces of amber found in the sands, and other

formations evidently alluvial, those met with on the sea-coasts of

certain countries, and especially Pomerania, come undoubtedly from the

above geological formation; for the organic matters found still adhering

to the amber leave no doubt as to its primitive place. Amber does not,

therefore, belong to any postdiluvian or modern soil, since its native

bed is covered by three or four series of strata, often of considerable

thickness, and well characterised; proceeding upwards from the plastic

clay which includes the amber: these are, the crag limestone, the bone

gypsum, with its marls, the marly limestone, the upper marl sandstone,

which covers it, and, lastly, the freshwater or lacustrine formation,

often so thick, and composed of calcareous and siliceous rocks.

The amber bed is not, however, always covered with all these strata; and

it is even rare to see a great mass of one of them above the ground

which contains it; because, were it buried under such strata, it would

be difficult to meet with such circumstances as would lay it

spontaneously open to the day. But by comparing observations made in

different places, relatively to the patches of these formations, which

cover the amber deposits, we find that no other mineral formations have

been ever seen among them except those above detailed, and thus learn

that its geological locality is completely determined.

The proper yellow amber, therefore, or the Borussic, from the country

where it has been most abundantly found, belongs to the plastic clay

formation, intermediate, in England, between the chalk and the London

clay. It is sometimes interposed in thin plates between the layers of

the lignites, but more towards the bark of the fibrous lignites, which

retain the form of the wood, than towards the middle of the trunk of the

tree; a position analogous to that of the resinous matters in our

existing ligneous vegetables. The fibrous lignites which thus contain

amber belong to the dicotyledinous woods. Hence that substance seems to

have been formed during the life of the vegetable upon which it is now

encrusted. It must be remembered that the grounds containing the amber

are often replete with the sulphates of iron, alumina, and lime, or at

least with the pyritous elements of these salts. Some specimens of amber

have a surface figured with irregular meshes, indicating a sort of

shrinkage from consolidation, and consequently a matter that was at one

time fluid, viscid, or merely soft. From optical examination, Dr.

Brewster has concluded amber to be of vegetable origin.

The different bodies included in the amber, distinguishable from its

transparence, demonstrate, indeed, in the most convincing manner, its

primitive state of liquidity or softness. These bodies have long

exercised the skill of naturalists. They are generally insects, or

remains of insects, and sometimes leaves, stalks, or other portions of

vegetables. Certain families of insects occur more abundantly than

others. Thus the _hymenoptera_, or insects with four naked membranaceous

wings, as the bee and wasp, and the _diptera_, or insects with two

wings, as gnats, flies, gadflies, &c.; then come the spider tribe; some

_coleoptera_ (insects with crustaceous shells or elytra, which shut

together, and form a longitudinal suture down the back,) or beetles,

principally those which live on trees; such as the _elaterides_, or

leapers, and the _chrysomelida_. The lepidoptera, or insects with four

membranaceous wings, and pterigostea covered with mail-like scales, are

very rare in amber. We perceive from this enumeration, which results

from the labours of Germar, Schweiger, &c., that the insects enveloped

in this resinous matter are in general such as sit on the trunks of

trees, or live in the fissures of their bark. Hitherto, it has not been

found possible to refer them to any living species; but it has been

observed in general that they resemble more the insects of hot climates

than those of the temperate zones.

The districts where amber occurs in a condition fit for mining

operations are not numerous; but those in which it is met with in small

scattered bits are very abundant. Its principal exploitation is in

Eastern Prussia, on the coasts of the Baltic sea, from Memel to

Dantzick, particularly in the neighbourhood of Konigsberg, along the

shore which runs north and south from Grossdirschheim to Pillau, and in

several other places near Dantzick.

It is collected upon this coast in several ways; 1. In the beds of small

streams which run near the villages, and in rounded fragments without

bark, or in the sand-banks of rivers, in pieces thrown back by the sea,

and rounded by the waves. 2. If the pieces thrown up by the waters are

not numerous, the fishers, clothed in a leather dress, wade into the sea

up to the neck, seek to discover the amber by looking along its surface,

and seize it with bag nets, hung at the end of very long poles. They

conclude that a great deal of amber has been detached from the cliffs by

the sea, when many pieces of lignite (wood coal) are seen afloat. This

mode of collecting amber is not free from danger, and the fishers,

therefore, advance in troops, to lend each other aid in case of

accident; but their success, even thus, is most precarious. 3. The third

method of searching for amber is a real mining operation: it consists in

digging pits upon the borders of the sandy downs, sometimes to a depth

of more than 130 feet. 4. The last mode is by exploring the precipitous

sea cliffs in boats, and detaching masses of loose soil from them with

long poles terminating in iron hooks; a very hazardous employment. They

search the cliffs with great care at the level, where the amber nodules

commonly lie, and loosen the seams with their hooks; in which business

the boats are sometimes broken against the precipices, or sunk by an

avalanche of rubbish.

Amber occurs in Sicily, disseminated in beds of clay and marl, which lie

below the crag limestone. It is accompanied with bitumen; and, though a

scanty deposit, it is mined for sale. The pieces are coated with a kind

of whitish bark, present a variety of colours, and include many insects.

Amber is found in a great many places in the sandy districts of Poland,

at a very great distance from the sea, where it is mixed with cones of

the pine. In Saxony it is met with in the neighbourhood of Pretsch and

Wittemberg, in a bituminous clay mingled with lignite. At the embouchure

of the Jenissey, in Siberia, it occurs likewise along with lignite; as

also in Greenland.

Fine amber is considerably valued for making ornamental objects, and the

coarser kinds for certain uses in chemistry, medicine, and the arts. The

oriental nations prize more highly than the people of Europe trinkets

made of amber; and hence the chief commerce of the Pomeranian article is

with Turkey. The Prussian government is said to draw an annual revenue

of 17,000 dollars from amber. A good piece of a pound weight fetches 50

dollars. A mass weighing 13 pounds was picked up not long since in

Prussia, for which 5000 dollars were offered, and which would bring, in

the opinion of the Armenian merchants, from 30,000 to 40,000 dollars at

Constantinople. At one time it was customary to bake the opaque pieces

of amber in sand, at a gentle heat, for several hours, in order to make

it transparent, or to digest it in hot rapeseed oil, with the same view;

but how far these processes were advantageous does not appear.

When amber is to be worked into trinkets, it is first split on a leaden

plate at a lathe (see GEMS, _Cutting of_), and then smoothed into shape

on a Swedish whetstone. It is polished on the lathe with chalk and

water, or vegetable oil, and finished by friction with flannel. In these

processes the amber is apt to become highly electrical, very hot, and

even to fly into fragments. Hence, the artists work the pieces time

about, so as to keep each of them cool, and feebly excited. The men are

often seized with nervous tremors in their wrists and arms from the

electricity. Pieces of amber may be neatly joined by smearing their

edges with linseed oil, and pressing them strongly together, while they

are held over a charcoal fire. Solid specimens of amber, reported to

have been altogether fused by a particular application of heat, are now

shown in the royal cabinet of Dresden.

A strong and durable _varnish_ is made by dissolving amber in drying

linseed oil. For this purpose, however, the amber must be previously

heated in an iron pot, over a clear red fire, till it soften and be

semi-liquefied. The oil, previously heated, is to be now poured in, with

much stirring, in the proportion of 10 ounces to the pound of amber;

and after the incorporation is complete, and the liquid somewhat cooled,

a pound of oil of turpentine must be added. Some persons prescribe 2

ounces of melted shellac, though by this means they are apt to deepen

the colour, already rendered too dark by the roasting.

The fine black varnish of the coachmakers is said to be prepared by

melting 16 ounces of amber in an iron pot, adding to it half a pint of

drying linseed oil, boiling hot, of powdered resin and asphaltum 3

ounces each: when the materials are well united, by stirring over the

fire, they are to be removed, and, after cooling for some time, a pint

of warm oil of turpentine is to be introduced.

The _oil of amber_ enters into the composition of the old perfume called

_eau de luce_; and is convertible, by the action of a small quantity of

strong nitric acid, into a viscid mass like shoemakers’ rosin, which has

a strong odour of musk, and, under the name of artificial musk, has been

prescribed, in alcoholic solution, as a remedy against hooping cough,

and other spasmodic diseases.

Acid of amber (_succinic acid_) is a delicate reagent, in chemistry, for

separating red oxide of iron from compound metallic solutions.

AMBERGRIS. (_Ambregric_, Fr.; _Ambra_, Germ.).--A morbid secretion of

the liver of the spermaceti whale (physeter macrocephalus), found

usually swimming upon the sea. It occurs upon the coasts of Coromandel,

Japan, the Moluccas, and Madagascar, and has sometimes been extracted

from the rectum of whales in the South Sea fishery. It has a gray-white

colour, often with a black streak, or is marbled, yellow and black; has

a strong but rather agreeable smell, a fatty taste, is lighter than

water, melts at 60° C. (140° F.), dissolves readily in absolute alcohol,

in ether, and in both fat and volatile oils. It contains 85% of the

fragrant substance called _ambreine_. This is extracted from ambergris

by digestion with alcohol of 0·827, filtering the solution, and leaving

it to spontaneous evaporation. It is thus obtained in the form of

delicate white tufts: which are convertible into ambreic acid by the

action of nitric acid. Ambergris is used in perfumery.

AMIANTHUS. A mineral in silky filaments, called also ASBESTUS.

AMMONIA. A chemical compound, called also _volatile alkali_. This

substance, in its purest state, is a highly pungent gas, possessed of

all the mechanical properties of the air, but very condensable with

water. It consists of 3 volumes of hydrogen and 1 of azote condensed

into two volumes; and hence its density is 0·591, atmospheric air being

1·000. By strong compression and refrigeration it may be liquefied into

a fluid, whose specific gravity is 0·76 compared to water 1·000.

Ammonia gas is composed by weight of 82·53 azote and 17·47 hydrogen in

100 parts. It is obtained by mixing muriate of ammonia, commonly called

sal ammoniac, with quicklime, in a retort or still, applying a moderate

heat, and receiving the gas either over mercury for chemical

experiments, or in water to make liquid ammonia for the purposes of

medicine and the arts. Woulfe’s apparatus is commonly employed for this

condensation.

Ammonia is generated in a great many operations, and especially in the

decomposition of many organic substances, by fire or fermentation. Urine

left to itself for a few days is found to contain much carbonate of

ammonia, and hence this substance was at one time collected in great

quantities for the manufacture of certain salts of ammonia, and is still

used for its alkaline properties in making alum, scouring wool, &c. When

woollen rags, horns, bones, and other animal substances are decomposed

in close vessels by fire, they evolve a large quantity of ammonia, which

distils over in the form of a carbonate. The main source of ammonia now

in this country, for commercial purposes, is the coal gas works. A large

quantity of watery fluid is condensed in their tar pits, which contains,

chiefly ammonia combined with sulphuretted hydrogen and carbonic acid.

When this water is saturated with muriatic acid and evaporated it yields

muriate of ammonia, or sal ammoniac, somewhat impure, which is

afterwards purified by sublimation. See CARBONATE OF AMMONIA and SAL

AMMONIAC.

The soot of chimnies where coal is burned contains both sulphate and

carbonate of ammonia, and was extensively employed, at one time, to

manufacture these salts.

In making water of ammonia on the great scale, a cast iron still should

be preferred, and equal weights of quicklime and sal ammoniac should be

brought to the consistence of a pap, with water, before the heat is

applied. In this case, a refrigeratory worm or globe should be

interposed between the adopter tube of the capital of the still and the

bottles of Woulfe’s apparatus. The muriate of lime, or chloride of

calcium, which is left in the still when the whole ammonia is expelled,

is of no value. Water is capable of condensing easily about one third of

its weight of ammonia gas, or 460 times its bulk. The following table of

the quantity of ammonia in 100 parts by weight of its aqueous

combinations, at successive densities, is the result of very careful

experiments made by me, and recorded in the Philosophical Magazine for

March, 1821.

_Table of Water of Ammonia or Volatile Alkali, by Dr. Ure._

+------+-------+------+-----------+--------+-------------------------+

|Water |Ammonia|Water | Specific | Mean | |

| of | in | in |gravity by |specific| Equivalent primes. |

|0·900.| 100. | 100. |experiment.|gravity.| |

+------+-------+------+-----------+--------+-------------------------+

| 100 |26·500 |73·500| 0·9000 | | |

| 95 |25·175 |74·825| 0·9045 |0·90452 | _Wat. Am._|

| 90 |23·850 |76·150| 0·9090 |0·90909 | 24 + 76, 6 to 1 |

| 85 |22·525 |77·475| 0·9133 |0·91370 | |

| 80 |21·200 |78·800| 0·9177 |0·91838 | 21·25 + 78·75, 7 to 1 |

| 75 |19·875 |80·125| 0·9227 |0·92308 | |

| 70 |18·550 |81·450| 0·9275 |0·92780 | 19·1 + 80·9, 8 to 1 |

| 65 |17·225 |82·775| 0·9320 |0·93264 | 17·35 + 82·65, 9 to 1 |

| 60 |15·900 |84·100| 0·9363 |0·93750 | 15·9 + 84·1, 10 to 1 |

| 55 |14·575 |85·425| 0·9410 |0·94241 | 14·66 + 85·34, 11 to 1 |

| 50 |13·250 |86·750| 0·9455 |0·94737 | 13·60 + 86·40, 12 to 1 |

| 45 |11·925 |88·075| 0·9510 |0·95238 | 11·9 + 88·1, 14 to 1 |

| 40 |10·600 |89·400| 0·9564 |0·95744 | 11·2 + 88·8, 15 to 1 |

| 35 | 9·275 |90·725| 0·9614 |0·96256 | |

| 30 | 7·950 |92·050| 0·9662 |0·96774 | 8·63 + 91·37, 20 to 1 |

| 25 | 6·625 |93·375| 0·9716 |0·97297 | 7 + 93, 25 to 1 |

| 20 | 5·300 |94·700| 0·9768 |0·97826 | 6 + 94, 30 to 1 |

| 15 | 3·975 |96·025| 0·9828 |0·98360 | 4·5 + 95·5, 40 to 1 |

| 10 | 2·650 |97·350| 0·9887 |0·98900 | 3 + 97, 60 to 1 |

| 5 | 1·325 |98·675| 0·9945 |0·99447 | |

+------+-------+------+-----------+--------+-------------------------+

AMMONIAC, gum-resin. This is the inspissated juice of an umbelliferous

plant (the _dorema armeniacum_) which grows in Persia. It comes to us

either in small white tears clustered together, or in brownish lumps,

containing many impurities. It possesses a peculiar smell, somewhat like

that of assafœtida, and a bitterish taste. It is employed in medicine.

Its only use in the arts is for forming a cement to join broken pieces

of china and glass, which may be prepared as follows: Take isinglass 1

ounce, distilled water 6 ounces, boil together down to 3 ounces, and add

1-1/2 ounce of strong spirit of wine;--boil this mixture for a minute or

two; strain it; add, while hot, first, half an ounce of a milky emulsion

of gum ammoniac, and then five drams of an alcoholic solution of resin

mastic. This resembles a substance sold in the London shops, under the

name of _diamond cement_. The recipe was given me by a respectable

dispensing chemist.

AMORPHOUS. _Without shape._ Said of mineral and other substances which

occur in forms not easy to be defined.

ANALYSIS. The art of resolving a compound substance or machine into its

constituent parts. Every manufacturer should so study this art, in the

proper treatises, and schools of Chemistry or Mechanics, as to enable

him properly to understand and regulate his business.

[Illustration: 6]

ANCHOR. (_Ancre_, Fr.; _Anker_, Germ.) An iron hook of considerable

weight and strength, for enabling a ship to lay hold of the ground, and

fix itself in a certain situation by means of a rope called the cable.

It is an instrument of the greatest importance to the navigator, since

upon its taking and keeping hold depends his safety upon many

occasions, especially near a lee shore, where he might be otherwise

stranded or shipwrecked. Anchors are generally made of wrought iron,

except among nations who cannot work this metal well, and who therefore

use copper. The mode in which an anchor operates will be understood from

inspection of _fig._ 6., where, from the direction of the strain, it is

obvious that the anchor cannot move without ploughing up the ground in

which its hook or fluke is sunk. When this, however, unluckily takes

place, from the nature of the ground, from the mode of insertion of the

anchor, or from the violence of the winds or currents, it is called

_dragging the anchor_. When the hold is good, the cable or the buried

arm will sooner break than the ship will drive. Anchors are of different

sizes, and have different names, according to the purposes they serve;

thus there are, _sheet_, _best bower_, _small bower_, _spare_, _stream_,

and _kedge anchors_. Ships of the first class have seven anchors, and

smaller vessels, such as brigs and schooners, three.

[Illustration: 7]

The manufacture of anchors requires great knowledge of the structure of

iron, and skill in the art of working it. I shall give, here, a brief

notice of the improved system introduced by Mr. Perring, clerk of the

cheque at Plymouth, in which the proportions of the parts are admirably

adapted to the strains they are likely to suffer. In _fig._ 7. A is the

_shank_; B, the _arm_ or _fluke_; C, the _palm_; D, the _blade_; E, the

_square_; F, the _nut_; G, the _ring_; H, the _crown_.

Formerly the shank was made of a number of square iron rods, laid

parallel together in a cylindrical form, and bound by iron hoops. When

they were welded into one bar, the exterior rods could not fail to be

partially burned and wasted by the strong heat. Mr. Perring abated this

evil by using bars of the whole breadth of the shank, and placing them

right over each other, hooping them and welding them together at two

heats into one solid mass. To any one who has seen the working of

puddled iron, with a heavy mill hammer, this operation will not appear

difficult.

He formed the crown with bars similarly distributed with those of the

shank. His mode of uniting the flukes to the crown is probably the most

valuable part of his invention. The bars and half the breadth of the

anchor are first welded separately, and then placed side by side, where

the upper half is worked into one mass, while the lower part is left

disunited, but has carrier iron bars, or _porters_, as these

prolongation rods are commonly called, welded to the extremity of each

portion. The lower part is now heated and placed in the clamping

machine, which is merely an iron plate firmly bolted to a mass of

timber, and bearing upon its surface four iron pins. One end of the

crown is placed between the first of these pins, and passed under an

iron strap; the other end is brought between the other pins, and is bent

by the leverage power of the elongated rods or porters.

Thus a part of the arm being formed out of the crown gives much greater

security that a true union of fibres is effected, than when the junction

was made merely by a short scarf.

The angular opening upon the side opposite B H, _fig._ 7., is filled

with the _chock_, formed of short iron bars placed upright. When this

has been firmly welded, the truss-piece is brought over it. This piece

is made of plates similar to the above, except that their edges are here

horizontal. The truss-piece is half the breadth of the arm; so that when

united to the crown, it constitutes, with the other parts, the total

breadth of the arms at those places.

The shank is now shut upon the crown; the square is formed, and the nuts

welded to it; the hole is punched out for the ring, and the shank is

then fashioned.

The blade is made much in the way above described. In making the palm,

an iron rod is first bent into the approximate form, notching it so that

it may more readily take the desired shape. To one end a _porter_ rod is

fastened, by which the palm is carried and turned round in the fire

during the progress of the fabrication. Iron plates are next laid side

by side upon the rod, and the joint at the middle is broken by another

plate laid over it. When the mass is worked, its under side is filled up

by similar plates, and the whole is completely welded; pieces being

added to the sides, if necessary, to form the angles of the palm. The

blade is then shut on to the palm, after which the part of the arm

attached to the blade is united to that which constitutes the crown. The

smith-work of the anchor is now finished.

The junction, or shutting on, as the workmen call it, of the several

members of an anchor, is effected by an instrument called a _monkey_,

which is merely a mass of iron raised to a certain height, between

parallel uprights, as in the pile engine or vertical ram, and let fall

upon the metal previously brought to a welding heat.

The _monkey_ and the _hercules_, both silly, trivial names, are similar

instruments, and are usually worked, like a portable pile engine, by the

hands of several labourers, pulling separate ropes. Many other modes of

manufacturing anchors have been devised, in which mechanical power is

more extensively resorted to.

The upper end of the shank F (_fig._ 7.) is squared to receive and hold

the stock steadily, and keep it from turning. To prevent it shifting

along, there are two knobs or tenon-like projections. The point of the

angle H, between the arms and the shank, is sometimes called the throat.

The arm B C generally makes an angle of 56° with the shank A; it is

either round or polygonal, and about half the length of the shank.

The _stock_ of the anchor (_fig._ 6.) is made of oak. It consists of two

beams which embrace the _square_, and are firmly united by iron bolts

and hoops, as shown in the figure. The stock is usually somewhat longer

than the shank, has in the middle a thickness about one-twelfth of its

length, but tapers at its under side to nearly one half this thickness

at the extremities. In small anchors the stock is frequently made of

iron; but in this case it does not embrace the anchor, but goes through

a hole made in the square, which is swelled out on purpose.

The weight of anchors for different vessels is proportioned to the

tonnage; a good rule being to make the anchor in hundredweights

one-twentieth of the number of tons of the burden. Thus a ship of 1000

tons would require a sheet anchor of 50 cwts. Ships of war are provided

with somewhat heavier anchors.

Several new forms and constructions of anchors were proposed under Mr.

Piper’s patent of November, 1822, by the adoption of which great

advantages as to strength were anticipated over every other form or

construction previously made.

The particular object was to preserve such a disposition of the fibres

of the metal as should afford the greatest possible strength; in doing

which the crossing or bending of the fibres at the junctions of the

shank, flukes, and crown, where great strength is required, has been

avoided as much as possible, so that the fibres are not disturbed or

injured.

In this respect most anchors are defective; for in connecting the shanks

to the crown-pieces, the grain of the metal is either crossed, or so

much curved, as to strain the fibre, and consequently induce a weakness

where the greatest strength is required. And, further, the very

considerable thicknesses of metal which are to be brought into immediate

contact by means of the hammer in forging anchors upon the old

construction, render it highly probable that faulty places may be left

within the mass, though they be externally imperceptible. Mr. Piper’s

leading principle was, that the fibre of the metal should run nearly

straight in all the parts where strength is particularly required.

[Illustration: 8]

_Fig._ 8. shows an anchor with one tumbling fluke, which passes through

the forked or branched part of the shank. The lower part of this anchor,

answering to the crown, has a spindle through it, upon which the fluke

turns, and a pin is there introduced for the purpose of confining the

fluke when in a holding position. This shank is formed of a solid piece

of wrought iron, the fibres of which run straight, and at the crown

holes are pierced, which merely bulge the metal without bending the

fibres round so as to strain them. The arm and fluke, also, are formed

of one piece punched through without curling or crossing the fibre, and

the spindle which holds the arm to the crown is likewise straight. This

spindle extends some distance on each side of the anchor, and is

intended to answer the purpose of a stock; for when either of the ends

of the spindle comes in contact with the ground, the anchor will be

thrown over into a holding position; or an iron stock may be introduced

near the shackle, instead of these projecting ends. In the descent of

the anchor, the fluke will fall over towards that side which is nearest

the ground, and will there be ready to take hold when the anchor is

drawn forward.

[Illustration: 9]

_Fig._ 9. is another anchor upon the same principle, but slightly varied

in form from the last. In this the forked part of the shank is closer

than in the former, and there are two arms or flukes connected to the

crown-pieces, one of which falls into its holding position as the anchor

comes to the ground, and is held at its proper angle by the other fluke

stopping against the shank.

[Illustration: 10]

_Fig._ 10. represents another variation in the form of these improved

anchors, having two tumbling flukes, which are both intended to take

hold of the ground at the same time. The shank is here, as before, made

without crossing the grain of the iron, and the eyes for admitting the

bolt at the crown and at the shackle are punched out of the solid, not

formed by welding or turning the iron round. In this form a guard is

introduced at the crown, to answer the purpose of a stock, by turning

the flukes over into a holding position. The arms and flukes are made,

as before described, of the straight fibre of the iron punched through,

and the flukes are fixed to the spindle, which passes through the

crown-piece.

[Illustration: 11]

_Fig._ 11. has a shank without any fork, but formed straight throughout;

the guard here is an elongated frame of iron, for the same purpose as a

stock, and is, with the tumbling flukes, fastened to the spindle, which

passes through the crown of the anchor, and causes the flukes to fall

into their holding position.

The principles of these new anchors are considered to consist in shanks

which are made of straight lengths of metal, and finished so that the

fibres of the iron shall not be injured by cross-shuts or uncertain

welding; also each arm and palm is made in one solid piece, and finished

in straight lines, so that the fibres will not be altered, and the

shaft-pin or spindle will also be in one straight line; and this is the

improvement claimed. These anchors being made in separate pieces, give a

great advantage to the workman to execute each part perfectly; for he

will not have such heavy weights to lift when hot, which will render

these anchors much stronger, with less weight; and if any accident

should happen to them, any part may be taken separate from the others to

be repaired, and several of those parts of the anchor which may be

likely to break may be carried on board, in case of accident. This

anchor is so contrived that one of thirty hundred weight may be taken to

pieces and put together again, by one man, in twenty minutes; it may

also be dismounted, and stowed in any part of the ship, in as little

room as straight bars of iron, and speedily put together again.

[Illustration: 12]

The anchor (_fig._ 12.) patented by Mr. Brunton, in February, 1822, has

its stock introduced at the crown part, for the purpose of turning it

over into a holding position. The shank is perforated through the solid,

in two places, with elliptical apertures, for the purpose of giving it a

greater stability, and more effectually resisting the strain to which

the anchor may be subjected. The stock is a cylindrical iron rod, held

at its extremities by lateral braces, which are bolted to the shank.

_Fig._ 12. shows the form of the anchor. The shank is seen upright, with

one of the flukes projecting in its front; the horizontal iron stock is

at bottom; and the oblique braces are bolted to both shank and stock.

The ends of the stock, from the shoulder, are formed dove-tailed, and

oval in the vertical direction, and are protruded through apertures in

the braces, also oval, but in the horizontal direction, and counter

sunk. When the ends of the stock have been thus introduced through the

holes, the braces are securely bolted to the shank; the ends of the

stock are then spread, by hammering into the counter-sunk holes of the

braces, and by that means they are made firm.

An anchor of this description is considered by the patentee to possess

considerable advantage, particularly in point of stability, over the

ordinary construction of anchors, and is economical, inasmuch as a less

weight of metal will give, upon this plan, an equal degree of strength.

An ingenious form of anchor was made the subject of a patent, by

Lieutenant Rodgers, of the Royal Navy, in 1828, and was afterwards

modified by him in a second patent, obtained in August, 1829. The whole

of the parts of the anchor are to be bound together by means of iron

bands or hoops, in place of bolts or pins.

[Illustration: 13 14 15 16]

_Fig._ 13. is a side view of a complete anchor, formed upon his last

improved construction, and _fig._ 14., a plan of the same; _fig._ 15.,

an end view of the crown and flukes, or arms; _fig._ 16. represents the

two principal iron plates, _a_, _a_, of which the shank is constructed,

but so as to form parts of the stump arms to which the flukes are to be

connected.

The crown piece is to be welded to the stump piece, _c c_, _fig._ 16.,

as well as to the end _l_ of the centre piece _h h_, and the scarfs _m

m_ are to be cut to receive the arms or flukes. Previously, however, to

uniting the arms or flukes with the stump arms, the crown and throat of

the anchor are to be strengthened, by the application of the crown slabs

_n n_, _fig._ 16., which are to be welded upon each side of the crown,

overlapping the end of the pillar _h_, and the throat or knees of the

stump arms and the crown piece. The stump arms are then to be

strengthened in a similar manner, by the thin flat pieces _p p_, which

are to be welded upon each side. The palms are united to the flukes in

the usual way, and the flukes are also united to the stump arms by means

of the long scarfs _m m_. When the shank of the anchor has been thus

formed, and united with the flukes, the anchor smith’s work may be said

to be complete.

[Illustration: 17]

Another of the improvements in the construction of anchors, claimed

under this patent, consists in a new method of affixing the stock upon

the shank of the anchor, which is effected in the following manner: in

_fig._ 14. the stock is shown affixed to the anchor; in _fig._ 17. it is

shown detached. It may be made either of one or two pieces of timber, as

may be found most convenient. It is, however, to be observed that the

stock is to be completed before fitting on to the shank. After the stock

is shaped, a hole is to be made through the middle of it, to fit that

part of the shank to which it is to be affixed. Two stock plates are

then to be let in, one on each side of the stock, and made fast by

counter sunk nails and straps, or hoops; other straps or hoops of iron

are also to be placed round the stock, as usual.

In place of nuts, formed upon the shank of the anchor, it is proposed to

secure the stock by means of a hoop and a key, shown above and below J,

in _fig._ 14. By this contrivance, the stock is prevented from going

nearer to the crown of the anchor than it ought to do, and the key

prevents it from sliding towards the shackle.

Since fitting the stock to the shank of an anchor, by this method,

prevents the use of a ring, as in the ordinary manner, the patentee says

that he in all cases substitutes a shackle for the ring, and which is

all that is required for a chain cable; but, when a hempen cable is to

be used, he connects a ring to the usual shackle, by means of a joining

shackle, as in _figs._ 13. and 14.

Mr. Rodgers proposes, under another patent, dated July, 1833, to alter

the size and form of the palms; having found from experience that

anchors with small palms will not only hold better than with large ones,

but that the arms of the anchor, even without any palms, have been found

to take more secure hold of the ground than anchors of the old

construction, of similar weight and length. He has, accordingly, fixed

upon one-fifth of the length of the arm, as a suitable proportion for

the length or depth of the palm. He makes the palms, also, broader than

they are long or deep.

ANIMÉ. A resin of a pale brown yellow colour, transparent and brittle.

It exudes from the courbaril of Cayenne, a tree which grows also in

various parts of South America. It occurs in pieces of various sizes,

and it often contains so many insects belonging to living species, as to

have merited its name, as being animated. It contains about a fifth of

one per cent. of a volatile oil, which gives it an agreeable odour.

Alcohol does not dissolve the genuine animé, as I have ascertained by

careful experiments; nor does caoutchoucine; but a mixture of the two,

in equal parts, softens it into a tremulous jelly, though it will not

produce a liquid solution. When reduced to this state, the insects can

be easily picked out, without injury to their most delicate parts.

The specific gravity of the different specimens of animé which I tried,

varied from 1·054 to 1·057. When exposed to heat, in a glass retort over

a spirit flame, it softens, and, by careful management, it may be

brought into liquid fusion, without discolouration. It then exhales a

few white vapours, of an ambrosiacal odour, which being condensed in

water, and the liquid being tested, is found to be succinic acid.

_Author._

It is extensively used by the varnish makers, who fuse it at a pretty

high heat, and in this state combine it with their oils, or other

varnishes.

ANKER. A liquid measure of Amsterdam, which contains 32 gallons English.

ANNEALING or NEALING. (_Le recuit_, Fr.; _das anlassen_, Germ.) A

process by which glass is rendered less frangible; and metals, which

have become brittle, either in consequence of fusion, or long-continued

hammering, are again rendered malleable. When a glass vessel is allowed

to cool immediately after being made, it will often sustain the shock of

a pistol-bullet, or any other blunt body falling into it from a

considerable height; while a small splinter of flint, or an angular

fragment of quartz, dropped gently into it, makes it sometimes

immediately, sometimes after a few minutes, fly to pieces with great

violence. This extreme fragility is prevented by annealing, or placing

the vessels in an oven, where they take several hours or even some days

to cool. Similar phenomena are exhibited in a higher degree by

glass-tears, or Prince Rupert’s drops. They are procured by letting

drops of melted glass fall into cold water. Their form resembles that of

a pear, rounded at one extremity, and tapering to a very slender tail at

the other. If a part of the tail be broken off, the whole drop flies to

pieces with a loud explosion; and yet the tail of a drop may be cut away

by a glass-cutter’s wheel, or the thick end may be struck smartly with

a hammer, without the fear of sustaining any injury. When heated to

redness, and permitted to cool gradually in the open air, they lose

these peculiarities, and do not differ sensibly from common glass.

The properties of unannealed glass depend on a peculiar structure,

extending uniformly through its whole substance; and the bursting of a

glass drop by breaking off the tail, or of an unannealed glass vessel,

by dropping a piece of flint into it, arises from a crack being thus

begun, which afterwards extends its ramifications in different

directions throughout the glass.

When metals have been extended to a certain degree under the hammer,

they become brittle, and incapable of being further extended without

cracking. In this case the workman restores their malleability by

annealing, or heating them red-hot. The rationale of this process seems

to be, that the hammering and extension of the metal destroy the kind of

arrangement which the particles of the metal had previous to the

hammering; and that the annealing, by softening the metal, enables it to

recover its original structure.

Of late years a mode has been discovered of rendering cast iron

malleable, without subjecting it to the action of puddling. The process

is somewhat similar to that employed in annealing glass. The metal is

kept for several hours at a temperature a little below its fusing point,

and then allowed to cool slowly. In this manner vessels are made of cast

iron which can sustain considerable violence, without being broken. See

STEEL, softening of.

ANNOTTO. (_Rocou_, or _roucou_, Fr.; _orleans_, Germ.) A somewhat dry

and hard paste, brown without, and red within. It is usually imported in

cakes of two or three pounds weight, wrapped up in leaves of large

reeds, packed in casks, from America, where it is prepared from the

seeds of a certain tree, the _bixa orellana_, of Linnæus.

The pods of the tree being gathered, their seeds are taken out and

bruised; they are then transferred to a vat, which is called the

steeper, where they are mixed with as much water as covers them. Here

the substance is left for several weeks, or even months; it is now

squeezed through sieves placed above the steeper, that the water

containing the colouring matter in suspension may return, into the vat.

The residuum is preserved under the leaves of the anana (pine-apple)

tree, till it becomes hot by fermentation. It is again subjected to the

same operation, and this treatment is continued till no more colour

remains.

The substance thus extracted is passed through sieves, in order to

separate the remainder of the seeds, and the colour is allowed to

subside. The precipitate is boiled in coppers till it be reduced to a

consistent paste; it is then suffered to cool, and dried in the shade.

Instead of this long and painful labour, which occasions diseases by the

putrefaction induced, and which affords a spoiled product, Leblond

proposes simply to wash the seeds of annotto till they be entirely

deprived of their colour, which lies wholly on their surface; to

precipitate the colour by means of vinegar or lemon juice, and to boil

it up in the ordinary manner, or to drain it in bags, as is practised

with indigo.

The experiments which Vauquelin made on the seeds of annotto imported by

Leblond, confirmed the efficacy of the process which he proposed; and

the dyers ascertained that the annotto obtained in this manner was worth

at least four times more than that of commerce; that, moreover, it was

more easily employed; that it required less solvent; that it gave less

trouble in the copper, and furnished a purer colour.

Annotto dissolves better and more readily in alcohol than in water, when

it is introduced into the yellow varnishes for communicating an orange

tint.

The decoction of annotto in water has a strong peculiar odour, and a

disagreeable taste. Its colour is yellowish-red, and it remains a little

turbid. An alkaline solution renders its orange-yellow clearer and more

agreeable, while a small quantity of a whitish substance is separated

from it, which remains suspended in the liquid. If annotto be boiled in

water along with an alkali, it dissolves much better than when alone,

and the liquid has an orange hue.

The acids form with this liquor an orange-coloured precipitate, soluble

in alkalies, which communicate to it a deep orange colour. The

supernatant liquor retains only a pale yellow hue.

When annotto is used as a dye, it is always mixed with alkali, which

facilitates its solution, and gives it a colour inclining less to red.

The annotto is cut in pieces, and boiled for some instants in a copper

with its own weight of crude pearl ashes, provided the shade wanted do

not require less alkali. The cloths may be thereafter dyed in this bath,

either by these ingredients alone, or by adding others to modify the

colour; but annotto is seldom used for woollen, because the colours

which it gives are too fugitive, and may be obtained by more permanent

dyes. Hellot employed it to dye a stuff, prepared with alum and tartar;

but the colour acquired had little permanence. It is almost solely used

for silks.

For silks intended to become aurora and orange, it is sufficient to

scour them at the rate of 20 per cent. of soap. When they have been well

cleansed, they are immersed in a bath prepared with water, to which is

added a quantity of alkaline solution of annotto, more or less

considerable according to the shade that may be wanted. This bath should

have a mean temperature, between that of tepid and boiling water.

When the silk has become uniform, one of the hanks is taken out, washed,

and wrung, to see if the colour be sufficiently full; if it be not so,

more solution of annotto is added, and the silk is turned again round

the sticks: the solution keeps without alteration.

When the desired shade is obtained, nothing remains but to wash the

silk, and give it two beetlings at the river, in order to free it from

the redundant annotto, which would injure the lustre of the colour.

When raw silks are to be dyed, those naturally white are chosen, and

dyed in the annotto bath, which should not be more than tepid, or even

cold, in order that the alkali may not attack the gum of the silk, and

deprive it of the elasticity which it is desirable for it to preserve.

What has been now said regards the silks to which the aurora shades are

to be given; but to make an orange hue, which contains more red than the

aurora, it is requisite, after dyeing with annotto, to redden the silks

with vinegar, alum, or lemon juice. The acid, by saturating the alkali

employed for dissolving the annotto, destroys the shade of yellow that

the alkali had given, and restores it to its natural colour, which

inclines a good deal to red.

For the deep shades, the practice at Paris, as Macquer informs us, is to

pass the silks through alum; and if the colour be not red enough, they

are passed through a faint bath of brazil wood. At Lyons, the dyers who

use carthamus, sometimes employ old baths of this ingredient for dipping

the deep oranges.

When the orange hues have been reddened by alum, they must be washed at

the river; but it is not necessary to beetle them, unless the colour

turns out too red.

Shades may be obtained also by a single operation, which retain a

reddish tint, employing for the annotto bath a less proportion of alkali

than has been pointed out.

Guhliche recommends to avoid heat in the preparation of annotto. He

directs it to be placed in a glass vessel, or in a glazed earthen one;

to cover it with a solution of pure alkali; to leave the mixture at rest

for 24 hours; to decant the liquor, filter it, and add water repeatedly

to the residuum, leaving the mixture each time at rest for two or three

days, till the water is no longer coloured; to mix all these liquors,

and preserve the whole for use in a well-stopped vessel.

He macerates the silk for 12 hours in a solution of alum, at the rate of

an eighth of this salt for one part of silk, or in a water rendered

acidulous by the aceto-citric acid above described; and he wrings it

well on its coming out of this bath.

Silk thus prepared is put into the annotto bath quite cold. It is kept

in agitation there till it has taken the shade sought for; or the liquor

may be maintained at a heat far below ebullition. On being taken out of

the bath, the silk is to be washed and dried in the shade.

For lighter hues, a liquor less charged with colour is taken; and a

little of the acid liquid which has served for the mordant may be added,

or the dyed silk may be passed through the acidulous water.

We have seen the following preparation employed for cotton velvet:--one

part of quicklime, one of potash, two of soda.

Of these a ley is formed, in which one part of annotto is dissolved; and

the mixture is boiled for an hour and a half. This bath affords the

liveliest and most brilliant auroras. The buff (chamois) fugitive dye is

also obtained with this solution. For this purpose only a little is

wanted; but we must never forget, that the colours arising from annotto

are all fugitive.

Dr. John found in the pulp surrounding the unfermented fresh seeds,

which are about the size of little peas, 28 parts of colouring resinous

matter, 26·5 of vegetable gluten, 20 of ligneous fibre, 20 of colouring

extractive matter, 4 formed of matters analogous to vegetable gluten and

extractive, and a trace of spicy and acid matters.

The Gloucestershire cheese is coloured with annotto, in the proportion

of one cwt. to an ounce of the dye.

When used in calico-printing, it is usually mixed with potash or ammonia

and starch.

It is an appropriate substance for tingeing varnishes, oils, spirits,

&c.

The import duty upon annotto is 1_s._ per cwt. for flag, and 4_s._ for

other sorts. In 1834, 252,981 lbs. were imported; and in 1835, 163,421

lbs. The revenue from this drug in these two years, was 180_l._ and

98_l._ respectively.

ANTHRACITE, from ανθραξ, coal, is a species of coal found in the

transition rock formation, and is often called stone coal. It has a

grayish black, or iron black colour, an imperfectly metallic lustre,

conchoidal fracture, and a specific gravity of from 1·4 to 1·6, being,

therefore, much denser than the coal of the proper coal measures. It

consists wholly of carbon, with a small and variable proportion of

iron, silica, and alumina. It is difficult to kindle in separate masses,

and burns when in heaps or grates without smell or smoke, leaving

sometimes an earthy residuum. It has been little explored or worked in

the old world; but is extensively used in the United States of America,

and has become of late years a most valuable mineral to that country,

where it is burned in peculiar grates, adapted to its difficult

combustion. In Pennsylvania the anthracite coal formation has been

traced through a tract many miles in width, and extending across the two

entire counties of Luzerne and Schuylkill. At Maunch Chunk, upon the

Lehigh, 800 men were employed so far back as 1825, in digging this coal.

In that year 750,000 bushels were dispatched for Philadelphia. It is

worked there with little cost or labour, being situated on hills from

300 to 600 feet above the level of the neighbouring rivers and canals,

and existing in nearly horizontal beds, of from 15 to 40 feet in

thickness, covered by only a few feet of gravelly loam. At Portsmouth,

in Rhode Island, an extensive stratum of this coal has been worked, with

some interruptions, for 20 years; and more recently a mine of anthracite

has been opened at Worcester, in Massachusetts, at the head of the

Blackstone canal. It has been of late employed in South Wales, for

smelting iron, and in a cupola blast furnace, by Mr. Crane.

ANTIGUGGLER. A small syphon of metal, which is inserted into the mouths

of casks, or large bottles, called carboys, to admit air over the liquor

contained in them, and thus to facilitate their being emptied without

agitation or a guggling noise.

ANTIMONY. (_Antimoine_, Fr.; _Spiessglanz_, or _Spiessglass_, Ger.) The

only ore of this metal found in sufficient abundance to be smelted, is

the sulphuret, formerly called crude antimony. It occurs generally in

masses, consisting of needles closely aggregated, of a metallic lustre,

a lead-gray colour, inclining to steel-gray, which is unchanged in the

streak. The needles are extremely brittle, and melt even in the flame of

a candle, with the exhalation of a sulphureous smell. The powder of this

sulphuret is very black, and was employed by women in ancient times to

stain their eyebrows and eyelids. This ore consists in 100 parts of

72·86 metal, and 27·14 sulphur. Specific gravity from 4·13 to 4·6.

The veins of sulphuret of antimony occur associated with gangues of

quartz, sulphate of barytes, and carbonate of lime; those of Allémont

occur in the numerous fissures of a mica schist, evidently primitive.

In treating the ore to obtain the metal, the first object is to separate

the gangue, which was formerly done by filling crucibles with the mixed

materials, placing them on the hearth of an oven, and exposing them to a

moderate heat. As the sulphuret easily melts, it ran out through a hole

in the bottom of the crucible into a pot placed beneath, and out of the

reach of the fire. But the great loss from breakage of the crucibles,

has caused another method to be adopted. In this the broken ore, being

sorted, is laid on the bottom of a concave reverberatory hearth, where

it is reduced.

[Illustration: 18 19]

_Figs._ 18. 19. represent a wind or flame furnace, for the reduction of

antimony. The hearth is formed of sand and clay solidly beat together,

and slopes from all sides towards the middle, where it is connected with

the orifice _a_, which is closed with dense coal-ashes; _b_ is the air

channel up through the bridge; _c_, the door for introducing the

prepared ore, and running off the slags; _d_, the bridge; _e_, the

grate; _f_, the fire or fuel-door; _g_, the chimney. With 2 or 3 cwt. of

ore, the smelting process is completed in from 8 to 10 hours. The metal

thus obtained is not pure enough, but must be fused under coal dust, in

portions of 20 or 30 pounds, in crucibles, placed upon a reverberatory

hearth.

To obtain antimony free from iron, it should be fused with some

antimonic oxide in a crucible, whereby the iron is oxidized and

separated. The presence of arsenic in antimony is detected by the garlic

smell, emitted by such an alloy when heated at the blow-pipe; or,

better, by igniting it with nitre in a crucible; in which case,

insoluble antimonite and antimoniate of potash will be formed along with

soluble arseniate. Water digested upon the mixture, filtered, and then

tested with nitrate of silver, will afford the brown-red precipitate

characteristic of arsenic acid.

According to Berthier, the following materials afford, in smelting, an

excellent product of antimony: 100 parts of sulphuret; 60 of

hammerschlag (protoxide of iron from the shingling or rolling mills); 45

to 50 of carbonate of soda; and 10 of charcoal powder. From 65 to 70

parts of metallic antimony or regulus should be obtained. Glauber salts

may be used instead of soda. For another mode of smelting antimony, at

Malbosc, in the department of Ardèche, in France, see LIQUATION.

In the works where antimonial ores are smelted, by means of tartar

(argol), the alkaline scoriæ, which cover the metallic ingots, are not

rejected as useless, for they hold a certain quantity of antimonial

oxide in combination; a property of the potash flux, which is propitious

to the purity of the metal. These scoriæ, consisting of sulphuret of

potassium and antimonite of potash, being treated with water, undergo a

reciprocal decomposition; the elements of the water act on those of the

sulphuret, and the resulting alkaline hydro-sulphuret re-acts on the

antimonial solution, so as to form a species of _kermes mineral_, which

precipitates. This is dried, and sold at a low price as a veterinary

medicine, under the name of _kermes_, by the dry way.

Metallic antimony, as obtained by the preceding process, is the antimony

of commerce, but is not absolutely pure; containing frequently minute

portions of iron, lead, and even arsenic; the detection and separation

of which belong to the sciences of chemistry and pharmacy. Antimony is a

brittle metal, of a silvery white colour, with a tinge of blue, a

lamellar texture, and crystalline fracture. When heated at the blowpipe,

it melts with great readiness, and diffuses white vapours, possessing

somewhat of a garlic smell. If thrown in this melted state on a sheet of

flat paper, the globule sparkles, and bursts into a multitude of small

spheroids, which retain their incandescence for a long time, and run

about on the paper, leaving traces of the white oxide produced during

the combustion. When this oxide is fused with borax, or other vitrifying

matter, it imparts a yellow colour to it. Metallic antimony, treated

with hot nitric acid and in a concentrated state, is converted into a

powder, called antimonious acid, which is altogether insoluble in the

ordinary acid menstrua; a property by which the chemist can separate

that metal from lead, iron, copper, bismuth, and silver. According to

Bergman, the specific gravity of antimony is 6·86; but Haidinger makes

the Swedish native metal only 6·646. The alchemists had conceived the

most brilliant hopes of this metal; the facility with which it is

alloyed with gold, since its fumes alone render this most ductile metal

immediately brittle, led them to assign to it a royal lineage, and to

distinguish it by the title of _regulus_, or the little king.

Its chief employment now is in medicine, and in making the alloys called

type metal, stereotype metal, music plates, and Britannia-metal; the

first consisting of 6 of lead and 2 of antimony; the second of 6 of lead

and 1 of antimony; the third of lead, tin, and antimony; and the fourth

also of lead, tin, and antimony, with occasionally a little copper and

bismuth.--For Glass of antimony, see PASTES.

ANTISEPTICS. Substances which counteract the spontaneous decomposition

of animal and vegetable substances. These are chiefly culinary salt,

nitre, spices, and sugar, which operate partly by inducing a change in

the animal or vegetable fibres, and partly by rendering the aqueous

constituent unsusceptible of decomposition. See PROVISIONS, CURING OF.

ANVIL. A mass of iron, having a smooth and nearly flat top surface of

steel; upon which blacksmiths, and various other artificers, forge

metals with the hammer. The common anvil is usually made of seven

pieces: 1, the core, or body; 2, 3, 4, 5, the four corner pieces which

serve to enlarge its base; 6, the projecting end, which has a square

hole for the reception of the tail or shank of a chisel on which iron

bars may be cut through; and 7, the beak, or horizontal cone round which

rods or slips of metal may be turned into a circular form, as in making

rings. These 6 pieces are welded separately to the first, or core, and

then hammered into an uniform body. In manufacturing large anvils two

hearths are needed, in order to bring each of the two pieces to be

welded, to a proper heat by itself; and several men are employed in

working them together briskly in the welding state, by heavy swing

hammers. The steel facing is applied by welding in the same manner. The

anvil is then hardened by heating it to a cherry red, and plunging it

into cold water; a running stream being preferable to a pool or cistern.

The facing should not be too thick a plate, for, when such, it is apt to

crack in the hardening. The face of the anvil is now smoothed upon a

grindstone, and finally polished with emery and crocus, for all delicate

purposes of art.

The blacksmith, in general, sets his anvil loosely upon a wooden block,

and in preference on the root of an oak. But the cutlers and file-makers

fasten their anvils to a large block of stone; which is an advantage,

for the more firmly and solidly this tool is connected to the earth, the

more efficacious will be the blows of the hammer on any object placed

upon it.

AQUAFORTIS. Nitric acid, somewhat dilute, was so named by the alchemists

on account of its strong solvent and corrosive operation upon many

mineral, vegetable, and animal substances. See NITRIC ACID.

AQUA REGIA. The name given by the alchemists to that mixture of nitric

and muriatic acids which was best fitted to dissolve gold, styled by

them the king of the metals. It is now called _nitro-muriatic acid_.

AQUA VITÆ. The name very absurdly given to alcohol, when used as an

intoxicating beverage. It has been the _aqua mortis_ to myriads of the

human race; and will, probably, ere long destroy all the native tribes

of North America and Australia.

ARCHIL. A violet red paste used in dyeing, of which the substance called

_cudbear_ in Scotland (from _Cuthbert_, its first preparer in that

form), is a modification. Two kinds of archil are distinguished in

commerce, the _archil_ plant of the Canaries, and that of Auvergne. The

first is most esteemed: it is prepared from the _lichen rocellus_, which

grows on rocks adjoining the sea in the Canary and Cape de Verde

Islands, in Sardinia, Minorca, &c., as well as on the rocks of Sweden.

The second species is prepared from the _lichen parellus_, which grows

on the basaltic rocks of Auvergne.

There are several other species of lichen which might be employed in

producing an analogous dye, were they prepared, like the preceding, into

the substance called _archil_. Hellot gives the following method for

discovering if they possess this property. A little of the plant is to

be put into a glass vessel; it is to be moistened with ammonia and

lime-water in equal parts; a little muriate of ammonia (sal ammoniac) is

added; and the small vessel is corked. If the plant be of a nature to

afford a red dye, after three or four days, the small portion of liquid,

which will run off on inclining the vessel, now opened, will be tinged

of a crimson red, and the plant itself will have assumed this colour. If

the liquor or the plant does not take this colour, nothing need be hoped

for; and it is useless to attempt its preparation on the great scale.

Lewis says, however, that he has tested in this way a great many mosses,

and that most of them afforded him a yellow or reddish brown colour; but

that he obtained from only a small number a liquor of a deep red, which

communicated to cloth merely a yellowish-red colour.

Prepared archil gives out its colour very readily to water, ammonia, and

alcohol. Its solution in alcohol is used for filling spirit-of-wine

thermometers; and when these thermometers are well freed from air, the

liquor loses its colour in some years, as Abbé Nollet observed. The

contact of air restores the colour, which is destroyed anew, in vacuo,

in process of time. The watery infusion loses its colour, by the

privation of air, in a few days; a singular phenomenon, which merits new

researches.

The infusion of archil is of a crimson bordering on violet. As it

contains ammonia, which has already modified its natural colour, the

fixed alkalies can produce little change on it, only deepening the

colour a little, and making it more violet. Alum forms in it a

precipitate of a brown red; and the supernatant liquid retains a

yellowish-red colour. The solution of tin affords a reddish precipitate,

which falls down slowly; the supernatant liquid retains a feeble red

colour. The other metallic salts produce precipitates which offer

nothing remarkable.

The watery solution of archil applied to cold marble, penetrates it,

communicating a beautiful violet colour, or a blue bordering on purple,

which resists the air much longer than the archil colours applied to

other substances. Dufay says, that he has seen marble tinged with this

colour preserve it without alteration at the end of two years.