gas, and this attraction is promoted by elevating their
temperature. If a glass tube be filled with iron wire heated to
redness, and to one end of this tube a small vessel of boiling
water be attached, the steam evolved from the water will force its
way through the spaces between the red-hot wires in the tube, and
would be expected to issue from the remote end; but if the
substance issuing from the remote end of the tube be examined, it
will be found to be not steam, but hydrogen gas. If the quantity
of this gas be ascertained by weight, and also the quantity of
weight lost by the vessel of water at the other end of the tube,
it will be found that the loss of weight of the water by
evaporation will be nine times the weight of the hydrogen which
has issued from the remote end of the tube. If the weight of the
tube with the wire contained in it be next ascertained, it will be
found to be increased by eight times the weight of the hydrogen
which has issued from its remote end. From this it follows that
the weight of the hydrogen which has escaped from the tube, added
to the increase of weight which has been given to the wire in the
tube, makes up the whole weight of the water evaporated. If the
wire in the tube be next examined, it will be found that it has
suffered oxydation, or, in other words, that a new substance has
been formed in it called the oxyde of iron,—such substance being
a chemical compound formed of oxygen gas and iron.
It follows, therefore, that in this process the vapour of the
water, in passing through the tube, has been decomposed, and that,
having given up to the iron its oxygen, the hydrogen [Pg305]
alone escaped from the other end; and for every nine grains weight
of steam which passed through the tube, eight grains of oxygen
have been combined with the iron, and one grain of hydrogen has
escaped from the end of the tube.
Such are the class of effects on which the modern discovery of the
composition of water has been based. The merit of that discovery
has been shared between the celebrated English chemist, CAVENDISH,
and the not less celebrated French chemist, LAVOISIER, the chief
merit, however, being ascribed to the former.
We shall now briefly state the facts which led to this discovery,
with their dates, which will necessarily show the share which Watt
had in it.
When pure hydrogen gas is burned in an atmosphere of common air,
the process which takes place is now known to be nothing more than
the chemical combination of the hydrogen with eight times its own
weight of oxygen taken from the atmosphere, and the product of the
combustion is a quantity of water nine times the weight of the
hydrogen consumed. In the year 1776, Macquer, a well-known chemist
of that day, having held a saucer of white porcelain over a flame
of hydrogen which was burning at the mouth of a bottle, observed
that no smoke was produced and no soot deposited on the saucer. On
the other hand, he found that after the lapse of some time drops
of a clear pellucid liquid were perceptible on the saucer: this
liquid he submitted to analysis, and found it to be pure water.
Macquer mentioned this fact without comment or inference. It did
not occur to him that the water thus produced upon the saucer was
a substance which contained the hydrogen, which disappeared upon
combustion from the bottle.
On the 18th of April, 1781, Mr. Warltire addressed a letter to Dr.
Priestley, dated Birmingham, which letter is published in Dr.
Priestley's _Experiments on Air_, printed at Birmingham in 1781,
in which Warltire informs Priestley that he had fired a mixture of
hydrogen and common air in close glass vessels, and that, although
previously to firing the mixture the vessels were clean and dry, a
dewy deposit was [Pg306] observed afterwards on their sides. In
fact, water was present which was not present before.
The mixture was in this case fired by passing an electric spark
through the vessel; and it is now known that the effect produced
was the combination of the hydrogen, which formed part of the
mixture of airs in the vessel with the oxygen, which also formed
part of the same mixture.
It appears, from expressions in Warltire's letter, that the same
experiment had been previously made by Priestley, and the same
result observed by him.
The inference deduced from this by Warltire, and apparently
acquiesced in by Priestley, was, that whenever hydrogen was fired
in atmospheric air, the moisture, which is always more or less
sustained in the latter, was deposited; but neither of these
chemists perceived the real cause of the production of the water.
In the beginning of 1783, and not later than the 21st of April,
this experiment of Warltire and Priestley was repeated by
Cavendish, with this difference, that, instead of exploding the
mixture of hydrogen and common air, Cavendish exploded a mixture
of hydrogen and oxygen. He observed that water was present after
the explosion, but _inferred nothing_.
In a published paper dated April, 1783, Priestley announced a
further and most important result of his experiments. This was,
that in examining the weight of water produced by the explosion of
a mixture of oxygen and hydrogen, _that weight was found to be
precisely equal to the sum of the weights of the two gases_, which
disappeared in the process.
Immediately on observing this, Priestley, being then, as has been
already stated, Watt's near neighbour, communicated to the latter
what he had observed; upon which Watt immediately, viz. by a letter
dated the 26th of the same month, declared that the inevitable
consequence which followed from Priestley's observations was, that
water was a substance compounded of oxygen and hydrogen deprived of
[Pg307] a quantity of heat which was previously latent in them.[27]
The letter containing this inference was communicated immediately by
Priestley to Sir Joseph Banks, then President of the Royal Society,
to be laid before that body; and it is accordingly printed with its
proper date in the 74th volume of the _Philosophical Transactions_.
About two months after the date of Mr. Watt's letter just quoted,
Lavoisier made experiments on the combustion of oxygen and
hydrogen, and read a memoir before the Academy of Sciences in
Paris, in which his views of the formation of water by the
combination of these gases were developed. This paper, by
Lavoisier, was afterwards printed in the Memoirs of the Academy in
the year 1784. The experiments are there stated to have been made
in the month of June, 1783; and it is stated that Sir Charles
Blagden, who was present at the experiments, told Lavoisier that
Mr. Cavendish had already burned the same gases in close vessels,
and obtained a very sensible quantity of water.
On the 15th of January, 1784, the celebrated paper by Cavendish,
entitled "Experiments on Air," was read before the Royal Society,
and in this paper the composition of water by the union of oxygen
and hydrogen is explained.
In a controversy which afterwards ensued on the respective
[Pg308] claims of Cavendish and Lavoisier to credit for the
discovery of the composition of water, Sir Charles Blagden stated
that he had told Lavoisier, in June, 1783, more than Lavoisier
acknowledged, that he had not only told him that water was
produced by the combustion of the gases, but that his information
embraced the whole theory of the composition of water. This
declaration of Blagden was subsequent in date to January, 1784,
and there is no evidence of any explanation of this theory, verbal
or otherwise, having been given by Cavendish, or any other person,
antecedent to April, 1783.
From this brief statement of the facts and dates it will appear
that the merit of the discovery of the FACT, that the weight of
water resulting from the combustion of oxygen and hydrogen, is
equal to the sum of the weights of the oxygen and hydrogen which
disappear in the combustion, is due to Priestley; and that the
merit of the INFERENCE from that fact, that water is a compound
body, whose constituents are oxygen and hydrogen, is due to
Watt.[28] Whether those who subsequently deduced the same
inference, and promulgated the same theory, were or were not
informed of Mr. Watt's solution of the phenomenon, or what credit
may be due to any person, however eminent, who at any time
posterior to Mr. Watt's letter to Priestley, asserted that they
had, at a time antecedently to that, made the same inference
without having published it, or communicated it in such a manner
as to establish their claim upon rational and credible evidence,
are questions which we shall not here discuss, being contented
with establishing the right of Mr. Watt to the merit of the
discovery of the THEORY which explained the FACT discovered by
Priestley.
Even in his declining years, after he had withdrawn from the
active pursuits of his business, the least excitement was
sufficient to call into play the slumbering powers of his
inventive genius. No object could present itself to his notice
[Pg309] without receiving from that genius adaptation in form and
construction to useful purposes. As an example of this restless
activity of mind the following anecdote may be mentioned:—
A company at Glasgow had erected on the right bank of the Clyde
extensive buildings and powerful engines for supplying water to
the town. After this expense it was found that a source of water,
of very superior quality, existed on the left bank of the river.
To change the site of the establishment, after the expense which
had been incurred in its erection could not be contemplated, and
they therefore proposed to carry across the bottom of the river a
flexible suction pipe, the mouth of which should terminate in the
source from which the pure water was to be derived. This pipe was
to be supported by a flooring constructed upon the bed of the
river; but it was soon apparent that the construction of such a
flooring on a shifting and muddy bottom, full of inequalities, and
under several feet depth of water would require a greater
expenditure of capital than could with propriety be afforded. In
this difficulty the aged mechanician, for whom Glasgow itself had
been the earliest stage of professional labour, was applied to,
and instantly solved the problem. His attention is said to have
been attracted by a lobster which had been served at table: he set
himself about to contrive how, by mechanism, he could make an
apparatus of iron with joints which should have all the
flexibility of the tail of the lobster. He therefore proposed that
an articulated suction-pipe, capable of accommodating itself to
all the inequalities and to the possible changes of the bed of the
river, should be carried across it; that this flexible pipe should
be two feet in diameter, and one thousand feet in length. This
project the company accordingly caused to be executed after the
plans and drawings of Watt with the most complete success.[29]
[Pg310] Among the less prominent, though not less useful services
rendered by Watt to his country, may be mentioned the introduction
of the use of chlorine in bleaching. That invention of Berthollet
was introduced into England by Watt after his visit to Paris at
the close of the year 1786. He constructed all the necessary
apparatus for it, directed its erection, and superintended its
first performances. He then left it to his wife's father, Mr.
Macgregor, to carry on the processes.
When the properties of the gases began to occupy the attention of
chemists, attempts were made to apply them as a means of curing
diseases of the lungs. Dr. Beddoes pursued this inquiry with great
activity, and established, through the means of private
subscription, at Clifton, an institution in which this method of
cure was carefully investigated. The Pneumatic Institution (for so
it was called) has been rendered celebrated for having at its head
Humphry Davy, just then commencing his scientific career. Among
its founders was also numbered James Watt. Not content, however,
with affording the institution the sanction of his name, he
designed and caused to be constructed, at Soho, the apparatus used
for making the gases and administering them to the patients.
As the exalted powers of the mind of Watt, unfolded in his
numerous mechanical and philosophical inventions and discoveries,
have commanded the admiration and respect of his species, the
affection and love of his fellow men would not have been less
conciliated, had the qualities of his heart, as developed in his
private and personal relations, been as well known as the products
of his genius.
In the year 1764, Watt being then in the twenty-ninth year of his
age, married his cousin, Miss Miller. At this time he had fallen
into a state of despondency from his disappointments, which
produced a serious attack of nervous illness. The accomplishments
and superior understanding, the mildness of temper and goodness of
disposition of his wife, soon restored him to health. Of this
marriage four children, two sons and two daughters, were the
issue. Two of these children died in infancy; another, a daughter,
was married to Mr. Miller of Glasgow; and the fourth is the
[Pg311] present Mr. James Watt. In September, 1773, while her
husband was engaged in the design of the Caledonian canal in the
North of Scotland, Mrs. Watt died in child-bed of a fifth child,
who was still-born: "Would that I might here transcribe," says M.
Arago, "in all their simple beauty, some lines of the journal in
which he daily recorded his inmost thoughts, his fears, his hopes!
Would that you could see him, after this heavy affliction, pausing
on the threshold of that home, where 'HIS KIND WELCOMER' awaited
him no more; unable to summon courage to enter those rooms where
he was never more to meet 'THE COMFORT OF HIS LIFE!' Possibly, so
faithful a picture of a very deep sorrow might at last put to
silence those obstinate theorists, who, without being struck by
the thousands of instances to the contrary, do yet refuse
qualities of the heart to every man whose intellect has been
fostered by the fertile, sublime, and imperishable truths of the
exact sciences!"
After the lapse of some years Watt married Miss Macgregor, a
person who is represented to have possessed qualities of mind
which rendered her a companion every way suitable to her husband.
This lady survived Watt, and died in 1832 at an advanced age. Two
children were the issue of this second marriage.
In the year 1800 the extended patent right, which had been granted
to Boulton and Watt for their improved engine, expired, and at
this time Mr. Watt retired altogether from business. He was
succeeded by his two sons, the present Mr. James Watt, and
Gregory, one of the children of his second marriage. The works at
Soho continued to be conducted by the present Mr. Boulton, the son
of the partner of Mr. Watt, and the two Messrs. Watt. In 1804
Gregory Watt died at the age of twenty-seven, of a disease of the
chest. This afflicting event was deeply felt by Mr. Watt; but he
did not sink under it into that state of despondency in which he
has been represented to have fallen by M. Arago. On the contrary,
he continued to show the same activity of mind which had
characterised his whole [Pg312] life; nor did he lose that
interest which he always took in the pursuit of literature and in
society. The state of his feelings under this affliction is shown
by the following extracts from letters written by him at that
time, which have been published by Mr. Muirhead.
"Heathfield, January 26th, 1805.
* * "I, perhaps, have said too much to you and Mrs. Campbell
on the state of my mind. I, therefore, think it necessary to
say that _I am not low spirited_; and were you here, you would
find me as cheerful in the company of my friends as usual; my
feelings for the loss of poor Gregory are not passion, but a
deep regret that such was his and my lot.
"I know that all men must die, and I submit to the decrees
of nature, I hope with due reverence to the Disposer of
Events. Yet one stimulus to exertion is taken away, and,
somehow or other, I have lost my relish for my usual avocations.
Perhaps time may remedy that in some measure; meanwhile,
I do not neglect the means of amusement which are in my power."
"Heathfield, April 8th, 1805.
* * "It is rather mortifying to see how easily the want of
even the best of us is dispensed with in the world; but it is
very well it should be so. We here, however, cannot help
feeling a terrible blank in our family. When I look at my
son's books, his writings and drawings, I always say to
myself, where are the mind that conceived these things, and
the hands that executed them? In the course of nature, he
should have said so of mine; but it was otherwise ordered, and
our sorrow is unavailing. As Catullus says:—
—— 'Nunc it, per iter tenebricosum,
Illuc, unde negant redire quemquam.
At vobis male sit, malæ tenebræ
Orci, quæ omnia bella devoratis!'
"But Catullus was a heathen; let us hope that he (G.) is now
rejoicing in another and a better world, free from our cares,
griefs, and infirmities. Some one has said, I shall not wholly
die; and Gregory's name, his merits and virtues, will live at
least as long as those do who knew him. You are not, from
this, to conceive that we give way to grief; on the contrary,
you will find us as cheerful as we ought to be, and as much
disposed to enjoy the friends we have left as ever; but we
should approach to brutes if we had no regrets."
Mr. Watt, at the date of these letters, had entered on his
seventieth year, a period after which great mental exertions are
rarely made. [Pg313]
In the summer of 1819, symptoms of indisposition manifested
themselves which soon rendered Watt aware of his approaching
dissolution. "I am very sensible," said he to his afflicted
friends, "of the attachment you show me, and I hasten to thank you
for it, as I am now come to my last illness." He died on the 25th
of August, 1819. His remains were deposited in the church of
Handsworth, near his estate of Heathfield. His son has raised over
his grave a Gothic chapel, in the centre of which is placed a
statue by Chantrey.
The personal character of Watt could not fail to excite the
admiration and the love of those distinguished persons, whose
pride and happiness it was to be admitted to a share in the
friendship of the great engineer. Among these were reckoned some
of the men who will leave upon the present age the deepest and
most lasting impressions of their genius, and such persons have
bequeathed to posterity the sentiments with which he inspired
them. We cannot here do more justice to the personal character of
the subject of this notice than by repeating the portraiture of it
which has been given by three of the most distinguished of his
friends, and of the most illustrious men of the present age.
At a meeting convened in 1824, for erecting a monument to Watt,
Lord Brougham pronounced a speech, from which we extract the
following observations:—
"I had the happiness of knowing Mr. Watt, for many years, in the
intercourse of private life; and I will take upon me to bear a
testimony in which all who had that gratification I am sure will
join, that they who only knew his public merit, prodigious as
that was, knew but half his worth. Those who were admitted to
his society will readily allow that anything more pure, more
candid, more simple, more scrupulously loving of justice, than
the whole habits of his life and conversation, proved him to be,
was never known in society. One of the most astonishing
circumstances in this truly great man, was the versatility of
his talents. His accomplishments were so various, the powers of
his mind were so vast, and yet of such universal application,
that it was hard to say whether we should most admire the
extraordinary grasp of his understanding, or the accuracy of
nice research with which he could bring it to bear upon the most
minute objects of investigation. I forget of whom it was said,
that his mind resembled the trunk of an elephant, which can pick
up [Pg314] straws, and tear up trees by the roots. Mr. Watt, in
some sort, resembled the greatest and most celebrated of his own
inventions, of which we are at a loss whether most to wonder at
the power of grappling with the mightiest objects, or of
handling the most minute; so that, while nothing seems too large
for its grasp, nothing seems too small for the delicacy of its
touch, which can cleave rocks, and pour forth rivers from the
bowels of the earth, and, with perfect exactness, though not
with greater ease, fashion the head of a pin, or strike the
impress of some curious die. Now, those who knew Mr. Watt, had
to contemplate a man whose genius could create such an engine,
and indulge in the most abstruse speculations of philosophy, and
could at once pass from the most sublime researches of geology
and physical astronomy, the formation of our globe, and the
structure of the universe, to the manufacture of a needle or a
nail; who could discuss, in the same conversation, and with
equal accuracy, if not with the same consummate skill, the most
forbidding details of art and the elegances of classical
literature, the most abstruse branches of science and the
niceties of verbal criticism.
"There was one quality in Mr. Watt which most honourably
distinguished him from too many inventors, and was worthy of
all imitation—he was not only entirely free from jealousy,
but he exercised a careful and scrupulous self-denial, and was
anxious not to appear, even by accident, as appropriating to
himself that which he thought belonged to others. I have heard
him refuse the honour universally ascribed to him, of being
the inventor of the steam engine, and call himself simply its
improver; though, in my mind, to doubt his right to that
honour, would be as inaccurate as to question Sir Isaac
Newton's claim to his greatest discoveries, because Descartes
in mathematics, and Galileo in astronomy and mechanics, had
preceded him; or to deny the merits of his illustrious
successor, because galvanism was not his discovery, though,
before his time, it had remained as useless to science as the
instrument called a steam engine was to the arts before Mr.
Watt. The only jealousy I have known him to betray, was with
respect to others, in the nice adjustment he was fond of
giving to the claims of inventors. Justly prizing scientific
discovery above all other possessions, he deemed the title to
it so sacred, that you might hear him arguing by the hour to
settle disputed rights; and if you ever perceived his temper
ruffled, it was when one man's invention was claimed by, or
given to another; or when a clumsy adulation pressed upon
himself that which he knew to be not his own."
In the preface to the _Monastery_ Sir Walter Scott speaks of Watt
in the following terms:—
"There were assembled about half a score of our northern
lights. * * Amidst this company stood Mr. Watt, the man whose
genius discovered the means of multiplying our national
resources to a degree, perhaps, even beyond his own stupendous
powers of calculation and combination; bringing the treasures
of the abyss to the summit of the earth—giving the feeble arm
of man the momentum of an Afrite—commanding manufactures to
arise as the rod of the prophet produced water in the
desert—affording the means of dispensing with that time and
tide which wait for no man—and of sailing without that wind
which defied the command and threats of Xerxes himself. This
potent commander of the elements—this abridger of time and
space—this magician, whose cloudy [Pg315] machinery has
produced a change on the world, the effects of which,
extraordinary as they are, are, perhaps, only now beginning to
be felt—was not only the most profound man of science—the
most successful combiner of powers, and calculator of numbers,
as adapted to practical purposes—was not only one of the most
generally well informed, but one of the best and kindest of
human beings.
"There he stood, surrounded by the little band I have
mentioned of northern literati, men not less tenacious,
generally speaking, of their own fame and their own opinions,
than the national regiments are supposed to be jealous of the
high character which they have won upon service. Methinks I
yet see and hear what I shall never see or hear again. In his
eighty-second year, the alert, kind, benevolent old man, had
his attention alive to every one's question, his information
at every one's command.