973 



PRIESTLEY, JOSEPH. 



PRIESTLEY, JOSEPH. 



974 



Fixed Air" (1772); the same year he communicated to the Royal 

 Society his ' Observations on Different Kinds of Air,' to which the 

 Copley medal waa awarded in 1773. 



" No one," observes Dr. Thomson, "ever entered upon the study of 

 chemistry with more disadvantages than Dr. Priestley, and yet few 

 have occupied a more dignified station in it, or contributed a greater 

 number of new and important facts. The career which he selected 

 wag new, and he entered upon it free from those prejudices which 

 warped the judgment and limited the views of those who had been 

 regularly bred to the science. He possessed a sagacity capable of 

 overcoming every obstacle, and a turn for observation which enabled 

 him to profit by every phenomenon which presented itself to his view. 

 His habite of regularity were such that everything was registered as 

 soon as observed. He was perfectly sincere and unaffected, and the 

 discovery of truth seems to have been in every case his real and 

 undisguised object." He discovered oxygen gas, nitrous gas, nitrous 

 oxide gas, nitrous vapour, carbonic oxide gas, sulphurous oxide gas, 

 8uoric acid gas, muriatic gas, and ammoniacal gas. The first of these, 

 which he named dephlogisticated air, he discovered in 1774, having 

 obtained it by concentrating the sun's rays upon red precipitate of 

 mercury. He showed that the red colour of arterial blood resulted 

 from its combination with the oxygen of the atmosphere ; that tho 

 change produced in atmospheric air during the process of combustion 

 and putrefaction aroee from a similar abstraction of oxygen; and 

 recognised the property possessed by vegetables of restoring the 

 constituent thus abstracted. Moreover the pneumatic apparatus now 

 used by chemists was principally invented by him. " But though," 

 observes Dr. Thomson, " his chemical experiments were for the most 

 part accurate, they did not exhibit that preci.se chemical knowledge 

 which distinguished the experiments of some of his contemporaries. 

 He never attempted to determine the constituents of his gases, nor 

 their specific gravity, nor any other numerical result" Of this he 

 himself was doubtless aware; for in a letter written many years after 

 (1795), he observes, " As to chemical lectureship, I am now convinced 

 I could not have acquitted myself in it to proper advantage. . . . 

 Though I have made many discoveries in some branches of chemistry, 

 I never gave much attention to the common routine of it, and know 

 but little of the common processes." 



The theory promulgated by Lavoisier, though founded on the dis- 

 coveries of Cavendish and Priestley, was never adopted by the latter, 

 who continued to adhere to the phlogistic theory notwithstanding the 

 many facts and arguments adduced against it. 



\VLile at Leeds very advantageous proposals were mode to him to 

 accompany Captain Cook in his second voyage to the South Seas ; but 

 when about to prepare for his departure, it was intimated to him by 

 Sir. (afterwards Sir Joseph) Hanks, that objections to his religious 

 principles had been successfully urged by some of the ecclesiastical 

 members of the Board of Longitude. 



In 1773, through the recommendation of Dr. Price, he received the 

 appointment of librarian and literary companion to the Earl of Shel- 

 burne, with a salary of 2502. a year, a separate residence, and a 

 certainty for life in tho event of bis lordship's death or their previous 

 separation. In the second year of this engagement he accompanied 

 his patron through France, Flanders, Holland, and Germany. At 

 Paris his philosophical publications procured for him nn easy intro- 

 duction to several of the leading chemists and mathematicians, whom 

 be describes as professed atheists ; and by whom he was told that he 

 was the only individual they had ever met with, and of whose under- 

 standing they had any opinion, who was a believer in Christianity. 

 To combat their and similar prejudices, he wrote his ' Letters to a 

 Philosophical Unbeliever, containing an examination of the principal 

 objections to tho doctrines of natural religion, and especially those 

 contained in the writings of Mr. Hume' (1780) ; to which he after- 

 wards added the ' State of the Evidence of Revealed Religion, with 

 animadversions on the two last chapters of the first volume of Mr. 

 Gibbona's History of the Decline and Fall of the Roman Empire ' 

 (1787). While resident with Lord Shelburne, who allowed him 402. 

 a year towards defraying the expenses of his chemical experiments, 

 he printed the first four volumes of his ' Experiments and Observations 

 on Air,' 1774-7!'; a fifth appeared in 1780. He also wrote his 'Mis- 

 cellaneous Observations on Education' (1778), and an 'Introductory 

 Dissertation ' to Hartley's ' Observations on Man.' In this disserta- 

 tion, having expressed his doubts concerning the immateriality of the 

 sentient principle iu man, he-was denounced in most of the periodicals 

 as an unbeliever in revelation and an atheist. This led to the publi- 

 cation of Li* 'Disquisitions relating to Matter and Spirit' (1777), 

 wherein bis object is to nhow that " man is wholly material, and that 

 our only prospect of immortality is from the Christian doctrine of a 

 Resurrection." In the tame year appeared his work on the 'Doctrine 

 of Necessity.' 



The cause of the separation between Priestley and Lord Shelburne 

 (1780) has never transpired, and docs not appear to have been known 

 to Priextley himself. Some have attributed it to the odium to which 

 the works last mentioned subjected their author, and to the invidious 

 attacks which issued in almost all quarters from the press ; but what- 

 ever may have been their true motives, the conduct of both appears 

 to have been strictly honourable. Priestley retired with an annuity of 

 \fiOt. a year, and in 1787 Lord Shelburne made overtures for renewing 



the original engagement, which however Priestley thought proper to 

 decline. 



Among the many points of church doctrine which, aa we have seen, 

 were successively repudiated by Dr. Priestley, it is remarkable that 

 the doctrine of the Trinity should not have been hitherto included, at 

 least not in the same unqualified manner. In a letter to Mr. Hender- 

 son, dated August 1774, he has left a confession of his faith at that 

 time. " I believe," he writes, " the prophecies in our Bible were given 

 by God; that the gospels are true; that the doctrine of original sin 

 is absurd ; that the spirit of Goil only assists our apprehension ; that 

 the foreknowledge of God, held by the Arminians, is equal to the decree 

 of God held by tlie Calvinists; that they are both wrong; and the 

 truth is, the pains of hell are purgatory. Many things I yet doubt 

 of ; among these are the Trinity and the mediation of Christ." 



On leaving Lord Shelburne he became minister to the principal dis- 

 senting congregation at Birmingham, and a subscription was entere 1 

 into by his friends for defraying his philosophical experiments and 

 promoting his theological inquiries. His receipts from these sources 

 must, by his own account, have been very considerable. Offers were 

 also made to procure him a pension from government, but this he 

 declined. In 1782 he published his 'History of the Corruptions of 

 Christianity,' 2 vols. 8vo. A refutation of the arguments contained 

 in this work waa proposed for one of the Hague prize essays ; and in 

 1785 the work itself was burnt by the common hangman in the city 

 of Dort. It was succeeded by his ' History of Early Opinions 

 concerning Jesus Christ,' 1786, 4 vols. 8vo. 



A literary warfare now ensued between Priestley and Dr. Horsley, 

 by both of whom it was carried on with much warmth. In a letter 

 to Dr. Price, dated Birmingham, January 27, 1791, he says, " With 

 respect to the church with which you have meddled but little, I have 

 long since drawn the sword and thrown away the scabbard, and am 

 very easy about the consequences." But he did not confine himself 

 to dealing with churchmen : his object was to obtain for the dissenters 

 what he considered to be their rights, and in the pursuit of which he 

 published about twenty volumes. He attacked certain positions 

 relating to the dissenters iu Blackstone's ' Commentaries ' with a vigour 

 and acrimony which seems to have surprised his more courteous and 

 feeble adversary. 



His ' Familiar Letters to the Inhabitants of Birmingham,' from the 

 ironical style in which they were written, exasperated even the popu- 

 lace, urged on by strong party feeling and bigotry. His ' Reply to 

 Burke's Reflections on the French Revolution," an event to which the 

 lower orders of Birmingham were at that time unfavourably disposed, 

 led to his being nominated a citizen of the French republic ; and the 

 occasion of a public dinner given, to say the least, with little judgment 

 or taste the state of the public feeling being taken into account 

 by some of his friends, July 14, 1791, in celebration of the anniver- 

 sary of the destruction of the Bastile, at which however Priestley 

 himself was not present, afforded to an excited mob the opportunity 

 of gratifying the malignity which they conceived they had grounds to 

 entertain towards him. After demolishing the place where the dinner 

 bad been given, they broke into his house, destroyed his philosophical 

 apparatus, a valuable collection of books, and a large number of 

 manuscripts, the result of many years' labour, after which they made 

 an unsuccessful attempt to burn the dwelling and what was left in it. 

 An eye-witness of the " riots " asserts that the high road, for full 

 half a mile of the house, was strewed with books, and that on entering 

 the library there was not a dozen volumes on the shelves, while the 

 floor was covered several inches deep with the torn manuscripts. Jn 

 the meantime, he and his family sought safety in flight. The first 

 two nights he passed in a post-chaise, the two succeeding on horse- 

 back, but owing less to his own apprehensions of danger than to those 

 of others. The sum awarded to him at the assizes as compensation 

 for the damage is not stated, but he tells us that it fell short of his 

 loss by 20002. Individual generosity made ample amends. Among 

 other instances of this kind, his brother-in-law made over to him tho 

 sum of 10,0002. invested in the French funds, besides an annuity of 

 2002. a year. 



After this he removed to Hackney as the successor of his deceased 

 friend Dr. Price; but finding his society shunned by many of his 

 former philosophical associates, among whom were the members of the 

 Royal Society, from whom he formally withdrew himself, and seeing 

 no prospect of enjoying permanent tranquillity in England, ho deter- 

 mined on quitting it. Accordingly, April 7, 1794, he embarked with 

 his family for America, and took up his abode at Northumberland in 

 Pennsylvania. A few days before his embarkation he was presented 

 with a silver inkstand bearing the inscription, " To Joseph Priestley, 

 LL.D., Sc., on his departure into exile, from a few members of the 

 University of Cambridge, who regret that this expression of their 

 estei-m is occasioned by the ingratitude in their country." He had 

 contemplated no difficulty in forming a Unitarian congregation iu 

 America ; but in this he was greatly disappointed. He found that 

 the majority disregarded religion ; and those who paid any attention 

 to it were more afraid of his doctrines than desirous of hearing them. 

 By the American government, the former democratic spirit of which 

 had subsided, he was looked upon as a spy in the interest of France. 

 " Tho change," he writes in a letter dated September 6, 1798, " that 

 has taken place is indeed hardly credible, as I have done nothing to 



