Goes to Leeds as minister of the Mill Hill Chapel—Resumes his studies in Speculative Theology—The Theological Repository—Becomes a Unitarian—Priestley as a controversialist—His Theory and Practice of Perspective—His literary characteristics—Begins his inquiries on Pneumatic Chemistry—His invention of soda-water—Receives the Copley Medal of the Royal Society.
Although Priestley lived in philosophic contentment with his lot at Warrington, happy in his occupations and in the society of congenial colleagues, the circumstances of the Academy were not fortunate. The institution never wholly recovered from the unhappy differences between the trustees and the first head of the Educational Staff, and in time many of the subscribers grew lukewarm in their support. Priestley had a remarkable power of adapting himself to his environment; he was one of the most even-tempered of men and had a capacity for being cheerful that would have extorted admiration even from Socrates. “But,” says Miss Aiken, “the Alma Mater of Warrington was ever a niggardly recompense of the distinguished abilities and virtues which were enlisted in her service.” One hundred pounds a year, with a house and a few boarders—hungry lads at ￡15 a year, exclusive of washing and candles—meant little towards the res angusta domi. Moreover, little Sarah Priestley had made her appearance, and the uncertain prospects which were before that young lady, coupled with the condition of her mother’s health, which was not wholly satisfactory at 67 Warrington, led him to contemplate the expediency of giving up school-mastering and of resuming his profession of the ministry. Accordingly he was induced to accept an invitation to take charge of the congregation of Mill Hill Chapel, at Leeds, where he was already pretty well known, and thither he removed in 1767.[12]
Although it was no part of his duty to preach when at Warrington, he had from choice continued the practice, and wishing to maintain the character of a Dissenting minister, he had, as we have already seen, been ordained whilst there. His tendency to stammer was still a difficulty. Indeed, whilst at Nantwich it was so marked that he had almost resolved to abandon the calling. By reading aloud and very slowly every day, and by taking pains, he in some measure got the better of his defect, but he never wholly overcame it.
At Leeds he found a liberal, friendly and harmonious congregation, to whom his services, of which he was not sparing, were very acceptable. There, he says, he had no unreasonable prejudices to contend with, so that he had full scope for every kind of exertion. His activity and zeal in the special duties of his office led him to prepare and print catechisms for the young and to form various classes of catechumens and to instruct them in the principles of religion. He also published discourses on “Family Prayer,” on the “Lord’s Supper” and on “Church Discipline,” some of which were not altogether to the liking of members of the Established Church. Indeed, the first of his controversial pieces was written in 68 answer to some angry remarks on one of these discourses written by a clergyman in the neighbourhood.
His return to the active duties of the ministry naturally induced him to resume the studies in Speculative Theology which had occupied him at Needham but which had been in large measure interrupted by the business of teaching at Nantwich and Warrington. He now published his Institutes of Natural and Revealed Religion, and began the publication of The Theological Repository, a collection of papers on theological questions, contributed by himself and a number of neighbouring ministers and others. The work eventually extended to six volumes, three of which were printed whilst he was at Leeds.
“The Theological Repository,” says the Rev. Charles Wicksteed,[13] “was one of those publications which will always appear from time to time in every body in which there is much activity and much freedom of thought. It had, however, a very slender circulation, and was very little read by any but theologians of the Liberal school. Indeed, it discussed questions which were viewed with terror by many even of the Liberal school itself, because it, in fact, purposely deserted the beaten track of opinion and opened out those questions on which difficulties began to be felt, or on which fresh light was wanted. It aimed at collecting the contributions of free, independent and thoughtful minds—towards correct ultimate decisions, without pretending itself to furnish those decisions. This is ever a position which the bigoted violently resent, which the unlearned cannot understand, on which even the candid and liberal often look with a dissatisfaction not unmingled with fear, but which is, notwithstanding, the essential preliminary of correct settled opinion in every age of thought. It is a position often assumed by the most contemplative and the most thoroughly honest men of the generation, but one which is never understood until the generation which produced and 69 neglected it is passed. If there were not this neutral ground on which inquiring spirits can meet, beyond the hackneyed and settled points in which alone the many are interested, there would be an end to thought, which in a short time would prove an end to active, healthy, influential and tested truth.”
Shortly after his removal to Leeds, Priestley avowed himself an adherent to that school of theological opinion which its enemies associate with the name of Fausto Sozzini; that is, he became what has been called a humanitarian, or a believer in the doctrine that Jesus Christ was in nature solely and truly a man, however highly exalted by God.
Sozzini’s doctrine brought down upon its teacher the ill-will of a Cracow mob; his house was wrecked, his books and manuscripts destroyed, his life threatened, and he was driven from the city. Two hundred years later the Socinian Priestley went through precisely the same experience. Wrecking the homes, pillaging the property and injuring the persons of heresiarchs might seem an extraordinary way of identifying oneself with the doctrine of the gentle author of the Sermon on the Mount if history had not made us pretty familiar with such spectacles. At Leeds, as already stated, Priestley published the first of the series of controversial pieces on religion and politics which ceased only with his death. By some strange irony of fate this man, who was by nature one of the most peaceable and peace-loving of men, singularly calm and dispassionate, not prone to disputation or given to wrangling, acquired the reputation of being perhaps the most cantankerous man of his time, who delighted in tilting against established usage, and whose hand, Ishmael-like, was against every man’s. By sheer force of circumstances 70 he became an indefatigable pamphleteer, apparently ever ready to vindicate the cause of civil and religious liberty, to champion the principles and conduct of Dissenters, and to attack what he considered the inveterate prejudices of the prevailing religion of his countrymen.
As a controversialist his methods were beyond reproach, and the arts of casuistry were wholly foreign to his character. He was so obviously sincere and fair-minded that he frequently overcame prejudice and disarmed criticism by his unconscious unwritten appeal to the finer instincts of his adversaries. He made many enemies but he won far more friends: the enemies were for the most part men whom history willingly lets die; the friends were of every sect, and some of them were among the chief glories of the eighteenth century.
The following characteristic letter to his friend, Miss Aiken, is interesting as illustrating the action of the active, eager mind which, as its owner says, found scope for every kind of exertion at this period of his life:—
“Leeds, 13th June 1769.
“Dear Miss Aikin,—You will be surprised when I tell you I write this on the behalf of Pascal Paoli and the brave Corsicans, but it is strictly true. Mr Turner of Wakefield, who says he reads your poems, not with admiration, but astonishment, insists upon my writing to you to request that a copy of your poem, called Corsica, may be sent to Mr Boswell, with permission to publish it for the benefit of those noble islanders. He is confident that it cannot fail greatly to promote their interest, now that a subscription is open for them, by raising a generous ardour in the cause of liberty and admiration of their glorious struggle in its defence. Its being written by a lady, he thinks, will be a circumstance very much in their favour and that of the poem, but there is no occasion for Mr Boswell to be acquainted with your name unless it be your own choice some time hence. I own I entirely agree with Mr 71 Turner in these sentiments, and therefore hope Miss Aikin will not refuse so reasonable a request, which will, at the same time, lay a great obligation on her friends in England and contribute to the relief of her own heroes in Corsica. Consider that you are as much a general as Tyrt?us was, and your poems (which, I am confident, are much better than his ever were) may have as great an effect as his. They may be the coup de grace to the French troops in that island, and Paoli, who reads English, will cause it to be printed in every history of that renowned island.
“Without any joke, I wish you would comply with this request. In this case you have only to send a corrected copy to me at Leeds, to Mr Johnson in London, and I will take care to introduce it to the notice of Mr Boswell by means of Mr Vaughan or Mrs Macauley, or some other of the friends of liberty and Corsica in London. The sooner this is done the better. Mr Turner regrets very much that it was not done some time ago. I shall not tell you what I think of your poems for more than twenty reasons, one of which is that I am not able to express it. We are now all expectation at the opening of every packet from Warrington.
“My piece on Perspective is nearly ready for the press. Come and see us before it is quite printed, and I will engage to teach you the whole art and mystery of it in a few hours. If you come a month after I may know no more about the matter than anybody else. I am about to make a bolder push than ever for the pillory, the King’s Bench Prison, or something worse. Tell Mr Aikin he may hug himself that I have no connection with the Academy. On Monday next Mr Turner and I set out on a visit to the Archdeacon at Richmond.
“With all our compliments to all your worthy family, I am, with the greatest cordiality, your friend and admirer,
“J. Priestley.”
Pasquale de Paoli, the Corsican patriot, whose struggles to secure the independence of his native island had excited warm sympathy in England and had enlisted the pen of Boswell, was at that time a refugee in this country, having been defeated, after a stubborn resistance, 72 by the French under Count Vaux. The poem on “Corsica,” one of the earliest and most beautiful of Miss Aikin’s productions, was written in 1768, at about the period of the appearance of Boswell’s Account of Corsica, but it was first published in 1773 in a collection of her poems, of which four editions, the first in 4to, the three others in 8vo were printed in that year.
The copy seen by Priestley was in manuscript. Whether it was shown to Boswell or to Paoli is not recorded.
The piece on Perspective was published in 1770, under the title of “A Familiar Introduction to the Theory and Practice of Perspective. With copperplates.” He gave as his reason for writing it that, having occasion to make drawings of philosophical instruments and apparatus he had felt the need of a work treating of perspective. It will be seen in the various editions of his works that the words “Priestley del” are engraved at the left-hand corner of the copperplates of the illustrations. The book had a considerable sale and was frequently recommended by drawing-masters. A second edition appeared in 1782 and it continued to be used well into the nineteenth century.
It is interesting to note that the first printed account of the use of india-rubber for the purpose of erasing lead pencil marks occurs in the preface to this work. It ran thus:—
“Since this work was printed off I have seen a substance excellently adapted to the purpose of wiping off from paper the marks of black lead pencil. It must therefore be of singular use to those who practise drawing. It is sold by Mr Nairne, mathematical instrument maker, opposite the Royal Exchange. He sells a cubical piece of about half an inch for three shillings, and he says it will last several years.”
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The “bolder push than ever for the pillory, the King’s Bench Prison, or something worse,” probably refers to the anonymous pieces which he published in support of “Wilkes and Liberty” in the course of the memorable struggle between the freeholders of Middlesex and the House of Commons concerning the rights of free representation by parliamentary constituencies which at that time agitated the country. Wilkes had shortly before the date of this letter been fined by the King’s Bench ￡1000 and sentenced to twenty-two months’ imprisonment for publishing an impious libel, and had been expelled from the House of Commons—to which, however, he was repeatedly returned by the electors of Middlesex.
The Richmond visit to Archdeacon Blackburne, whose son had been at the Warrington Academy, is memorable from the circumstance that on its occasion Priestley first met Theophilus Lindsey, with whom he contracted an intimate and lasting friendship, which greatly influenced the lives and fortunes of both, and of which Priestley subsequently wrote that it had been a source of more real satisfaction to him than any other circumstance in his whole life.
The busy pamphleteer found time, however, to put together more ambitious works than Wilkes and Liberty. The success of his History of Electricity induced him to attempt the compilation of the history of all the branches of experimental philosophy, and he made proposals to publish a History of Discoveries Relating to Vision Light and Colours. The subscription to this work was not, however, sufficient to induce him to proceed, and after a considerable outlay in the purchase of books and other material the project was abandoned.
Priestley was, perhaps, the most industrious bookmaker 74 of his age. Boswell indeed dubbed him a “literary Jack-of-all-Trades,” and he was busy with proof-sheets even to the day of his death. In fact, the closing act of his life, before he put his hand to his face to hide the last flicker of the vital spark, was to make a correction in a proof-sheet. He usually composed in shorthand, and much of this work was done in the family circle, sitting by the parlour fire. Conversation never disturbed him. Although his style is somewhat prolix, his language is simple and direct and his meaning invariably clear. Charges that his writings were hasty performances in nowise disturbed him. Indeed, he was wont to say that some of those that were most hurriedly done were among those that were best received. Whatever might have been the time he spent on their composition he was confident that more would not have contributed to their perfection in any essential particular, and about anything farther he was never very solicitous. His object, he said, was not to acquire the character of a fine writer but of a useful one. Pecuniary gain was never the chief object of his work; several of his books, indeed, were written with the prospect of certain loss. Many writers before and since the great lexicographer have left us what they have imagined to have been the secret of their success as literary craftsmen, and have told us of the means by which they gained their proficiency of composition and mastery of style. Priestley has no pretensions to be considered a master of style; nevertheless, it is of interest to learn how he acquired facility in writing the simple, unaffected English which characterises his literary work. It came, he said, from a practice of committing to writing as much as he could of the sermons he heard, and of composing 75 much in verse. With regard to the sermons, he says:—
“This practice I began very early, and continued it until I was able from the heads of a discourse to supply the rest myself. For, not troubling myself to commit to memory much of the amplification, and writing at home almost as much as I had heard, I insensibly acquired a habit of composing with great readiness, and from this practice I believe I have derived great advantage through life, composition seldom employing so much time as would be necessary to write in long hand anything I have published.”
As regards the verses, he says:—
“I was myself far from having any pretension to the character of a poet, but in the early part of my life I was a great versifier, and this, I believe, as well as my custom of writing after preachers, mentioned before, contributed to the ease with which I always wrote prose.”
If Priestley was not himself a poet, he was at least the cause of poetry in another. Miss Aikin once told him that it was the perusal of some verses of his that first induced her fledgling muse to soar—so that, he adds, “this country is in some measure indebted to me for one of the best poets it can boast of.” No example of Priestley’s abilities as a “versifier” has come down to us, but in that dainty little sketch of the Warrington society, by Miss Lucy Aikin, from which we have already quoted, allusion is made to his accomplishment.
“Both bouts rimés and vers de société were in fashion with the set. Once it was their custom to slip anonymous pieces into Mrs Priestley’s work-bag. One ‘copy of verses,’ a very eloquent one, puzzled all guessers a long time; at length it was traced to Dr Priestley’s self.”
To the man of science the special interest of Priestley’s connection with Leeds arises from the fact that he began there that fruitful series of inquiries, relating to what 76 he called “the doctrine of air,” which eventually raised him to the position of one of the greatest chemical discoverers of his time. The house in which he first lived whilst at Leeds was in Meadow Lane and adjoined the public brew house of Jakes and Nell. He was thereby led, in the outset, to amuse himself by making experiments on the “fixed air,” or carbonic acid, which is largely produced in the process of fermentation. When he removed to his second house in Basinghall Street, on the site where the schools now stand, he was under the necessity of making the fixed air for himself; and, as he distinctly and faithfully notes in his various publications on the subject, he was led to make one experiment after another until he became, what he does not state, the greatest master of pneumatic chemistry of his age.
When he began these experiments he tells us he knew very little of chemistry. Indeed, he says he had in a manner no idea on the subject before his attention was drawn to it in a course of lectures delivered in the Warrington Academy by Dr Turner of Liverpool. But, as he says, on the whole, this circumstance was no disadvantage to him, as in the situation in which he found himself he was led to devise an apparatus and processes of his own adapted to his peculiar views. If he had been previously accustomed to the usual chemical processes he might not have so easily thought of any other; and without new modes of operation he thinks he should hardly have discovered anything materially new. His means did not permit him to purchase expensive apparatus. Indeed, this very circumstance materially contributed to his success by making his apparatus so simple that his experiments could be readily repeated and their accuracy thereby ensured.
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His first contribution to Pneumatic Chemistry was published in 1772. It was a small pamphlet on a method of impregnating water with fixed air, which, being immediately translated into French, excited a great degree of attention to the subject, and this was much increased by the publication of his first experimental paper in the Philosophical Transactions of the Royal Society.
Priestley’s earliest method of impregnating water with carbonic acid consisted in exposing it to the gas above the surface of fermenting wort. This process was no doubt accompanied with many disadvantages and the resulting solution could not have been very palatable. Later on he adopted the method originally employed by Lane in 1709, although apparently in ignorance of Lane’s paper in the Philosophical Transactions, of making the gas from chalk and sulphuric acid and leading it directly into the water by means of a flexible tube provided with an intercepting bladder to retain any solid or acid substance projected from the effervescent materials in the generating flask. At about this period increased attention was being paid to the question of the supply of drinking water in the Navy, owing to the publication of Irving’s plan of making fresh water from sea-water by distillation, and Priestley conceived the idea that if some ready means could be devised of impregnating water with carbonic acid on shipboard the solution might be useful as a preventive of sea scurvy.
Priestley brought his idea to the knowledge of the Duke of Northumberland, and showed a sample of the impregnated water to Sir George Savile, who introduced him to Lord Sandwich, at that time First Lord of the 78 Admiralty in Lord North’s Administration. The Board of Admiralty thought the matter was of sufficient importance to ask for a report from the College of Physicians, and Priestley was requested to appear before that body in order to explain and illustrate his process. The report from the College was favourable, and in consequence two war-ships were fitted with the apparatus.
The idea that scurvy, in common with other so-called putrid diseases, was due to an insufficient supply of “fixed air” in the animal economy, and that it might be cured by the administration of that gas, originated with Dr Macbride about the middle of the eighteenth century, shortly after Black had established the individuality of the gas, and it was current doctrine with the faculty at the time of Priestley’s experiments. The reasons which Macbride gave in support of his hypothesis are contained in his Essays on Medical and Philosophical Subjects, and are sufficiently ingenious to be worth stating as characteristic of much of the therapeutics of the time. Macbride assumed that substances held together, and acquired the quality of firmness, by virtue of containing a “cementing principle,” which ensured the perfect cohesion of their constituent particles, and that as putrefaction resulted in the decomposition and disintegration of substances, putridity was connected with the loss or disappearance of this cementing or cohering principle. He found that “fixed air” was invariably produced when animal and vegetable substances putrefy, that a greater amount of fixed air is produced from vegetable substances than from animal substances, and that animal and vegetable matters putrefy more rapidly when mixed than when separate, and yield more fixed air in conjunction than apart.
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On the basis of these observations Macbride proceeded to explain the well-established fact that a diet mainly composed of animal food is apt to produce sea scurvy, the remedy for which is a sufficient supply of fresh vegetables, by assuming that the virtue of the vegetables was due to the evolution of a greater amount of carbonic acid in the process of digestion, the fixed air so liberated in the body counteracting, by its antiseptic powers, putridity in the circulating fluids.
We are not here concerned with the subsequent history of so-called ?rated or soda-water, as it came to be called, but it is worth noting that Priestley’s account of his process contains one remark which is not without significance in view of latter-day developments. He says:—
“I do not doubt but that, by the help of a condensing engine, water might be much more highly impregnated with the virtues of the Pyrmont spring, and it would not be difficult to contrive a method of doing it.”
The manufacture of these waters was subsequently taken up by Priestley’s friend and satellite, as he called himself, Richard Bewley, of Great Massingham, an apothecary, and the inventor of the well-known “mephitic julep.” Bewley appears to have discovered that the addition of a small quantity of carbonate of soda to the water enabled it to absorb and retain an increased quantity of carbonic acid, and to him, therefore, is due the credit of first making what was long called “acidulous soda-water.” The receipt for its manufacture and use, given by Henry of Manchester, is sufficiently quaint to be worth reproduction:—
“To prepare Mr Bewley’s julep dissolve three drachms of fossil alkali in each quart of water, and throw in streams of 80 fixed air till the alkaline taste be destroyed. This julep should not be prepared in too large quantities, and should be kept in bottles very closely corked and sealed. Four ounces of it may be taken at a time, drinking a draught of lemonade or water acidulated with vinegar or weak spirit of vitriol, by which means the fixed air will be extricated in the stomach.”
It is hardly to be supposed that the Royal Society Club in 1773 adopted all the social manners and customs of the period. Nevertheless, its members, who were among the most influential fellows of the Society, were evidently greatly impressed with the merits of Priestley’s soda-water, since the Council of the Society were moved to reward its discoverer with the Copley Medal.
In making the award on St Andrew’s Day 1773, Sir John Pringle, then President of the Royal Society, said:—
“For having learned from Dr Black that this fixed or mephitic air could in great abundance be procured from chalk by means of diluted spirits of vitriol; from Dr Macbride that this fluid was of a considerable antiseptic nature; from Dr Cavendish that it could in a large quantity be absorbed by water; and from Dr Brownrigg that it was this very air which gave the briskness and chief virtues to the Spa and Pyrmont waters; Dr Priestley, I say, so well instructed, conceived that common water impregnated with this fluid alone might be useful in medicine, particularly for sailors on long voyages, for curing or preventing the sea scurvy.”
To-day the Copley Medal is regarded as the highest award which it is in the power of the Society to bestow, and certainly no man starts his scientific career by acquiring it—not even for so signal an invention as that of soda-water.
Whilst Priestley was at Leeds a proposal was made to him that he should accompany Captain Cook in his second voyage to the South Seas. It probably arose 81 from his connection with the Admiralty in the matter of his invention. He tells us that as the terms were very advantageous he consented to it, the heads of his congregation agreeing to keep an assistant to supply his place during his absence. But Mr Banks informed him that he was objected to by some clergymen in the Board of Longitude, who had the direction of this business, on account of his religious principles. “Whether,” said Huxley, in commenting on this circumstance in the course of his speech at the unveiling of the Priestley statue in Birmingham in 1874, “these worthy ecclesiastics feared that Priestley’s presence among the ship’s company might expose his Majesty’s sloop Resolution to the fate which aforetime befell a certain ship that went from Joppa to Tarshish, or whether they were alarmed lest a Socinian should undermine that piety which in the days of Commodore Trunnion so strikingly characterised sailors, does not appear.” The appointment was given to Reinhold Forster, a man, as Priestley fully admitted, far better qualified for the position.