Chapter VII

Removes to London--Declines a pension--Renews his acquaintance with
Franklin--Goes to Birmingham--Becomes a member of the Lunar Society.

On leaving Calne, Priestley repaired to London. His position was somewhat precarious, as he had practically nothing but his allowance from Lord Shelburne to support him. This, although larger than the stipend he had enjoyed at Leeds, was barely sufficient for his growing family. Friends however were not wanting to come to his assistance. Indeed, during his residence at Calne, some of them observing, as they said, that many of his experiments had not been carried to their proper extent on account of the expense that would have attended them, proposed to supply him with whatever sums he should want for that purpose and named a hundred pounds per annum.

"This large subscription I declined," he says, "lest the discovery of
it (by the use that I should, of course, make of it) should give
umbrage to Lord Shelburne; but I consented to accept forty pounds per
annum, which from that time he (Dr Fothergill) regularly paid me from
the contribution of himself, Sir Theodore Jansen, Mr Constable and Sir
George Savile."

This sentence is characteristic of Priestley and of much of his autobiography. Probably no man with so many enemies had such troops of friends, and certainly none had so many and such generous benefactors. And the measure of their beneficence was only equalled by that of Priestley's gratitude and sense of obligation. Indeed, he says the chief object he had in putting together his memoirs was that he thought it right to leave behind him some account of his friends and benefactors, and accordingly we find that the incidents in his career are dwelt upon by him rather with the idea of illustrating his indebtedness to others than as records of his own achievements.

On his removal to London, where he contemplated resuming his profession as a teacher, Dr Fothergill and his co-subscribers considerably increased his allowance for experiments, whilst at the same time other friends were not less zealous that he should have the means to pursue his theological studies and to publish the fruits of his labours.

Indeed, all who could in any way assist seemed to vie with one another in help. Parker, the optician of Fleet Street, supplied him with every instrument that he wanted in glass, and Wedgwood, the potter, sent him innumerable retorts, tubes and other articles of clay. Without such assistance he could not have carried on his experiments, except on a very small scale and under great disadvantages.

During Lord Rockingham's administration, and subsequently at the beginning of that of Mr Pitt, some suggestions were made to provide Priestley with a pension to assist in defraying the expense of his inquiries.[14]

He however declined all overtures of this kind, wishing, as he said, to preserve himself independent of everything connected with the court, and preferring the assistance of individuals who were lovers of liberty as well as of science.

His winter's residence in London threw him constantly into the society of his old friend Franklin; indeed, he says, as members of the same club few days passed without their seeing one another, and their friendship ripened into the closest intimacy.

There can be no doubt that this intercourse with Franklin not only led Priestley to the study of natural science, but quickened and fostered his love of civil and political liberty. Priestley in his autobiography does ample justice to Franklin's efforts to maintain the union of the American Colonies with this country.

"But Franklin," says Mr Choate (Inaugural address as President of the
Birmingham and Midland Institute, October 23, 1903), "was more than a
staunch Loyalist. He was an Imperialist in the most stalwart sense of
the word, and on a very broad gauge."

His biographer, Parton, truly says:--

"It was one of Franklin's most cherished opinions that the greatness
of England and the happiness of America depended chiefly upon their
being cordially united. The 'country' which Franklin loved was not
England nor America, but the great and glorious Empire which these two
united to form."

In writing to Lord Kames, he said:--

"I have long been of opinion that the foundations of the future
grandeur and stability of the British Empire lie in America; and
though, like other foundations, they are low and little now, they are
nevertheless broad and strong enough to support the greatest political
structure that human wisdom ever yet erected."

In 1774 he wrote:--

"It has long appeared to me that the only true British policy was that
which aimed at the good of the whole British Empire, not that which
sought the advantage of one part in the disadvantage of the others;
therefore all measures of procuring gain to the Mother Country arising
from loss to her colonies, and all gain to the Colonies arising from
or occasioning loss to Britain, especially where the gain was small
and the loss was great ... I in my own mind condemned as improper,
partial, unjust and mischievous, tending to create dissensions and
weaken that union on which the strength, solidity and duration of the
Empire greatly depended; and I opposed, as far as my little powers
went, all proceedings, either here or in America, that in my opinion
had such tendency."

Priestley's testimony is no less explicit. He says:--

"The unity of the British Empire in all its parts was a favourite idea
of his. He used to compare it to a beautiful china vase which, if ever
broken, could never be put together again, and so great an admirer was
he of the British constitution that he said he saw no inconvenience
from its being extended over a great part of the globe."

In the autobiography we further read:--

"I can bear witness that he (Franklin) was so far from promoting, as
was generally supposed, that he took every method in his power to
prevent a rupture between the two countries. He urged so much the
doctrine of forbearance, that for some time he was unpopular with the
Americans on that account, as too much a friend to Great Britain. His
advice to them was to bear everything for the present, as they were
sure in time to outgrow all their grievances, as it could not be in
the power of the Mother Country to oppress them long.

"He dreaded the war, and often said that if the difference should come
to an open rupture it would be a war of _ten years_, and he should not
live to see the end of it. In reality the war lasted nearly eight
years, but he did not live to see the happy termination of it. That
the issue would be favourable to America he never doubted. The
English, he used to say, may take all our great towns, but that will
not give them possession of the country. The last day that he spent in
England, having given out that he should leave London the day before,
we passed together without any other company; and much of the time was
employed in reading American newspapers, especially accounts of the
reception which the 'Boston Port Bill' met with in America; and as he
read the addresses to the inhabitants of Boston from the places in the
neighbourhood the tears trickled down his cheeks."

What Franklin thought of Priestley may be gathered from the following extract from one of his letters to Vaughan, one of Priestley's Warrington pupils, written in October 1788 after his return to America:--

"Remember me affectionately to the good Dr Price and to the honest
heretic, Dr Priestley. I do not call him honest by way of distinction,
for I think all the heretics I have known have been virtuous men. They
have the virtue of fortitude, or they would not venture to own their
heresy; and they cannot afford to be deficient in any of the other
virtues, as that would give advantage to their many enemies; and they
have not, like orthodox sinners, such a number of friends to excuse or
justify them. Do not, however, mistake me. It is not to my good
friend's heresy that I impute his honesty. On the contrary 'tis his
honesty that has brought upon him the character of heretic."

In 1780, at the suggestion of his brother-in-law, John Wilkinson, one of his truest friends, Priestley was led to take up his residence in Birmingham. There were many circumstances which made this step desirable. In Birmingham he had friends prepared to welcome him and society in every way sympathetic and congenial. Moreover, he was desirous of resuming his ministerial duties, which had been intermitted for the past six or seven years, and an opportunity of doing so, with a congregation not less liberal than he had served at Leeds, offered itself, owing to the approaching retirement of Mr Hawkes from the charge of the New Meeting. As regards his philosophical pursuits he had the convenience of good workmen of every kind and he could count upon the practical sympathy and interest of men like Watt, his partner Boulton, Keir, Withering, Wedgwood, Erasmus Darwin, and the Galtons, all at that time living in Birmingham or in its vicinity. These men and their friends constituted indeed a cultured society without a parallel in any other town in the kingdom, except possibly in the Metropolis. The more eminent of them formed themselves into an association, to which frequent reference is made in the biographical literature of the period, on account of the part which it played in the social and intellectual life of the Midlands.

The Lunar Society of Birmingham appears to have been formed about the year 1766 by Matthew Boulton and Erasmus Darwin, at that time resident in Birmingham. The members were about ten or a dozen in number and met at each other's houses for dinner once a month on the Monday nearest to the full moon, in order to have the benefit of its light in returning home. They were in the habit of sitting down to dinner at two o'clock and their meeting lasted until eight.

Each member was allowed to bring a friend, and thus it happened that many distinguished men were recipients, at various times, of the Club's hospitality. Among them we find Wedgwood, Sir Joseph Banks, Sir William Herschel, Smeaton, the builder of the Eddystone Lighthouse; Dr Samuel Parr, the critic; Afzelius, the teacher of Berzelius; Solander, the well-known naturalist and traveller; De Luc and other names eminent in the literary and scientific annals of the century.

As might be supposed from what we know of its founders and their friends the constitution of the society was on the broadest possible basis. "We had nothing to do," says Priestley, "with the _religious_ or political principles of each other; we were united by a common love of _science_, which we thought sufficient to bring together persons of all distinctions--Christians, Jews, Mahometans and heathens, Monarchists and Republicans."

The invitations issued by the host were usually accompanied by some intimation of the nature of the impending symposium. Thus Watt writes to Darwin, under date Jan. 3, 1781:--

"I beg that you would impress on your memory the idea that you
promised to dine with sundry men of learning at my house on Monday
next, and that you will realise the idea. For your encouragement there
is a new book to be cut up, and it is to be determined whether or not
heat is a compound of phlogiston and empyreal air, and whether a
mirror can reflect the heat of the fire. I give you a friendly warning
that you may be found wanting whichever opinion you adopt in the
latter question, therefore be cautious. If you are meek and humble,
perhaps you may be told what light is made of, and also how to make
it, and the theory proved both by synthesis and analysis."

The discussions of the philosophic _convives_ were not, however, confined exclusively to chemistry.

"The period," says Mr Carrington Bolton, "was one of great activity in
the world of science; Laplace was applying his mathematical genius to
the problems of astronomy; Herschel was sweeping the heavens with his
gigantic telescopes; Galvani and Volta were laying the foundations of
a revolution in electricity; Count Rumford in Bavaria was devoting his
great energy to industrial and social economy; Hatton and Werner were
geologising in their respective countries; Haüy was systematising the
innumerable crystalline forms occurring in nature; the Montgolfier
brothers were experimenting with air-balloons and prophesying the yet
unsolved problem of aërial navigation; Captain James Cook returned
from his memorable voyages around the world, full of adventures and
novelties in nature: the application of steam to the driving of land
carriages and the propelling of boats was gradually being perfected by
patience and genius. These, together with the metaphysical and even
the political questions of the day, must have engrossed the attention
of the talented friends who dined together at the full moon."

A picturesque account of the Club is given in Mrs Schimmelpenninck's _Memoirs_. Mary Ann Schimmelpenninck (_née_ Galton) was the daughter of Mr Samuel Galton, a wealthy patron of letters and a man of considerable intellectual ability. He was interested in scientific pursuits and was a fellow of the Royal Society. His house at Barr, about seven or eight miles from Birmingham, was a notable place in the social life of the district, and the Lunar Society held some of its most delightful meetings under his hospitable roof, as Mrs Schimmelpenninck recalls. She thus writes of Dr Priestley:--

"A man of admirable simplicity, gentleness and kindness of heart,
united with great acuteness of intellect. I can never forget the
impression produced on me by the serene expression of his
countenance."

In his _Memoirs_ Richard Lovell Edgeworth says of the Society that it consisted of--

"Men of very different characters, but all devoted to literature and
science. This mutual intimacy has never been broken but by death, nor
have any of the number failed to distinguish themselves in science or
literature. Some may think I ought, with due modesty, to except
myself. Mr Keir, with his knowledge of the world and good sense; Dr
Small, with his benevolence and profound sagacity; ... Boulton, with
his mobility, quick perception and bold adventure; Watt, with his
strong inventive faculty, undeviating steadiness and bold resources;
Darwin, with his imagination, science and poetical excellence; and
Day, with his unwearied research after truth, his integrity and
eloquence, proved altogether such a society as few men have had the
good fortune to live with; such an assemblage of friends as fewer
still have had the happiness to possess and keep through life."

There can be no doubt that Priestley's coming to Birmingham contributed greatly to the interest of the meetings of the Lunar Society and reacted beneficially on Priestley himself by stimulating his activity and affording him the sympathy of congenial minds not less interested than he was in the study of natural science. As each meeting came round he was certain to find a gathering curious to hear of his latest experiments and eager to discuss with him their bearing upon the chemical doctrine of the period.

Priestley's influence and position in the Society may be inferred from the circumstance that almost immediately after he joined it Pneumatic Chemistry became one of the chief topics of discussion. This is amply demonstrated in the correspondence of its various members, which has been preserved to us in the biographies of Watt, Wedgwood and others, and in the scientific letters of Priestley, which have been collected and edited by Mr H. Carrington Bolton. One direct outcome of this interest is seen in Watt's connection with the History of the Discovery of the Composition of Water. It is reasonably certain that if Watt and Priestley had not foregathered round the festive board of the Lunar Society, Watt would not have been stimulated to theorise on the meaning and true significance of Priestley's experiments, and as to their bearing upon the fact that Priestley's dephlogisticated air (oxygen) and inflammable air (hydrogen) enter into the composition of water. Watt's claim to be considered as the discoverer of the composition of water rests upon his interpretation of the experimental phenomena made known to him by Priestley shortly after his arrival in Birmingham. The Water Controversy--a controversy which keenly excited the entire scientific world a generation or so ago--may be said to have arisen from the accident of Priestley's removal to Birmingham and to his association with the Lunar Society.

Priestley's connection with the Society influenced the progress of chemistry in this country both directly and indirectly. As already stated, he himself was greatly stimulated to accumulate chemical facts by his association with men like Boulton, Watt, Wedgwood, Keir, Darwin, who loved knowledge for its own sake, but who were at the same time quite alive to the material benefits which they and their fellow-men might derive from the pursuit of scientific inquiry. The measure of their interest may be gauged by the extent of their support, and by the readiness with which they furnished Priestley with the means to carry on his investigations. Priestley not only freely communicated to them the results of his labours, but he incidentally fixed their attention on a class of phenomena which, more than any other, were calculated to afford an insight into the real nature of chemical change, and to lead to a rational explanation of chemical phenomena.

Priestley was not consciously a casuist, but there can be no question that the interpretation which his active and ingenious mind occasionally led him to place upon his work not only served to blind himself, but was the means of obscuring the truth for a time from others. We have only to read the correspondence, already more than once alluded to, to find ample proof that such was the case. In a letter to Wedgwood, of March 30, 1781, Boulton writes:--

"We have long talked of phlogiston without knowing what we talked
about; but now that Dr Priestley hath brought the matter to light we
can pour that element out of one vessel into another; can tell how
much of it by accurate measurement is necessary to reduce a calx to a
metal, which is easily done, and without putting that calx into
contact with any visible thing. In short, this goddess of levity can
be measured and weighed like other matter. For the rest, I refer you
to the doctor himself."

In the following year (March 21, 1782) we find Priestley also writing to Wedgwood:--

"Before my late experiments, phlogiston was indeed almost given up by
the Lunar Society, but now it seems to be re-established."

How difficult it was to convince Priestley may be seen from the following extract from a letter to his friend Franklin, who was then in Paris, written at about the same time:--

"Birmingham, _June 24, 1782_.

"Please to inform the Duc de Rochefoucauld, whose civilities to me I
remember with pleasure, that my experiments are certainly inconsistent
with Mr Lavoisier's supposition of there being no such thing as
phlogiston, and that it is the addition of air, and not the loss of
anything, that converts a metal into a calx. In their usual state
calces of metals do not contain air, but that may be expelled by heat,
and after this I reduce them to a perfect metallic state by nothing
but inflammable air, which they imbibe _in toto_, without any
decomposition. I lately reduced 101 ounce measures of this air to two
by calx of lead, and that small remainder was still inflammable. I
explain Mr Lavoisier's experiments by supposing that _precipitate per
se_ [mercuric oxide] contains all the phlogiston of the metal mercury,
but in a different state; but I can show other calces which also
contain more phlogiston than the metals themselves. That mercury in
its metallic state does contain phlogiston or inflammable air is
evident from the production of nitrous air by the solution of it in
spirits of nitre, and I make _nitrous air_ from nothing but _nitrous
vapour_ and inflammable air; so that it indisputably consists of these
two ingredients. I have already ascertained the proportion of
inflammable air that enters into the composition of lead, tin, copper
and silver, and am proceeding with the other metals as fast as I can.
When the whole is completed I shall give you a further account of it.

"I am exceedingly concerned to find that it is so difficult a thing to
make _peace_; but I hope before the campaign is over all parties will
have had enough of _war_, and be sensible that they will gain nothing
by continuing it. If I had any voice in the business, the prospect of
seeing you in this country would be a strong additional motive to
accelerate the negotiations.

"With the greatest respect and every good wish.--I am, dear sir, yours
sincerely,
J. Priestley."

There were already many indications prior to 1780 that men were beginning to be troubled as to the sufficiency of Stahl's generalisation to account for the rapidly-accumulating mass of facts which the application of quantitative chemistry to the study of natural phenomena was bringing to light. Priestley's advent in Birmingham certainly retarded by the weight of his authority the growth in heterodoxy in that particular among the members of the Lunar Society, and indirectly therefore all whom they could influence.

The following letter from Keir is typical of many which passed between the members of the Society in reference to Priestley's work and of the discussions which it occasioned.

Keir to Priestley.

"The more we discover of Nature, the further we are removed from the
conceit of our being able to understand the operations.

"I wish M. Berthollet and his associates would relate their facts in
plain prose, that all men might understand them, and reserve their
poetry of the new nomenclature for their theoretical commentaries on
the facts.

"I have wished much to call on you to hear of the progress of your
experiments, but have been much indisposed with the rheumatism. I long
to know what acids you get with the other inflammable airs. If you get
different acids from the inflammable air made from sulphur and water,
that made from marine acid and copper (for I would avoid iron on
account of its plumbago and carbon), and that made from charcoal and
water:--I say, if these acids are different (suppose, according to my
notions, vitriolic, marine and fixed air), then will you not be
obliged to admit that there is not one inflammable but many
inflammables, which opinion you now think as heterodox as the
Athanasian System.

"However, there are wonderful resources in the dispute about
Phlogiston, by which either party can evade, so that I am less
sanguine than you are in my hopes of seeing it terminated. One
consolation remains, that in your experiments you cannot fail of
discovering something perhaps of as great or greater importance for us
to know."

Nevertheless, even in the Club itself there was at least one man who came under the influence of Priestley, but who eventually emancipated himself, and this was Withering, who, we are informed, read to them "a humorous piece in verse entitled 'The Life and Death of Phlogiston,' which was long remembered for its clever treatment and pointed wit."

That Priestley's influence still reigned in the Club, even down to 1803, may be inferred from the introduction to his essay, "The Doctrine of Phlogiston Established"--the last of his scientific papers--in which he says, "And now that Dr Crawford is dead, I hardly know of any person, except my friends of the Lunar Society of Birmingham, who adhere to the doctrine of Phlogiston."

As regards the history of the Lunar Society there is little more to tell. One by one its members submitted themselves to the arrest of the "fell sergeant," and eventually Keir, Watt, and Boulton, the founder, were the only survivors, and its meetings were gradually discontinued.

"But," says its historian, "the influence exerted by the Society did
not die; it had stimulated inquiry and quickened the zeal for
knowledge of all who had come within its influence, and this spirit
diffused and propagated itself in all directions."

Leonard Horner, who visited Soho in 1809, thus refers to the continued moral influence of the association:--

"The remnant of the Lunar Society," he says, "and the fresh
remembrance in others of the remarkable men who composed it, are very
interesting. The impression which they made is not yet worn out, but
shows itself to the second and third generation, in a spirit of
scientific curiosity and free inquiry, which even yet makes some stand
against Toryism and the love of gain."