[39] Dr. Priestley in his preliminary account of the discoveries and theories on respiration (Exp. on air v. 3 p. 356. abridged edit.) quotes Haller’s great work on Physiology. Haller quotes Mayow in three or four places; but it is no wonder the quotations did not strike Dr. Priestley with any curiosity to examine Mayow’s book, for Haller certainly did not understand his theory. For instance Lib. 8. § 13. Nitrum aereum. Si ad verum sensum nitri aerei hypothesis revocata fuisset parum utique ab eà differt quam novissimè proposuimus. Nitrum quidem ipsum incautiosius olim Physiologi in aere obvolitare scripserunt, et ex pluvià et nive colligi; idemque passim ex rupibus efflorescere (Sprat ex Henshaw p. 264 major cal. hum.) exque plantis et stercoribus educi (Fludd Niewentydt, 563-4. Mayow de nitro aereo. Lower de Corde c. 3. Thurston 52. 53. Besse Analyse tom 1 et en lettre en reponse à M. Helvet. 114.) id nitrum aiunt in pulmonibus ad sanguinem venire, et ab eo ruborem illum elegantem, et fermentationem (Mayow, Thurston penult. ess. T. 3 p. 265) et calorem sanguinis accedere aut vicissim sanguinem condensari.
Certainly the id nitrum, is not Mayow’s. M. Rosel seems first to have ascertained the existence of nitre in plants. A late experiment of Dr. Priestley’s, of which he gave an account in a letter to Dr. Wistar, seems to make it probable that there may be nitre in snow.
[40] Blumenbach’s Physiology, Caldwell’s translation, Philadelphia, 1795. § 162. Speaking of the theories of animal heat, “But all these hypotheses are embarrassed with innumerable difficulties; whereas on the other hand the utmost simplicity, and an entire correspondence with the phenomena of nature combine in recommending and confirming that doctrine in which the lungs are considered as the focus or fire place where animal heat is generated, and the deplogisticated part of the air which we breathe as the fuel that supports the vital flame. That justly celebrated character Jo. Mayow sketched out formerly the leading traces and the first great outlines of this doctrine which in our times has been greatly improved, extended and farther elucidated by the labours of the illustrious Crawford.”
Dr. Darwin however is certainly right in supposing that heat is evolved in many other processes of the animal economy, beside inspiration.
[41] See the translation of Scheele by Dr. John Reinhold Forster 1780 p. XIII.
In p. 437 of v. 5 of the analytical review of Hopson’s Chemistry, before Dr. Beddoes’s account of Mayow in 1790 the latter is stated as the author of discoveries that might have given rise to the present system of pneumatic Chemistry.
Two of Mayow’s Essays, viz. de Respiratione and de Rachitide, appear to have been published at Leyden, in 1671, the author who died at the age of 34, being then 26 years old. The propositions which I have thought it necessary to extract from Mayow’s work, (ed. of 1674, Oxford,) and which I shall insert, will give a concise, but faithful view of his discoveries and conjectures in pneumatic Chemistry.[42] The abridgements of Beddoes and Fourcroy, I have no opportunity to consult, and as Mayow’s book is far from being common, I have deemed it by no means an unnecessary labour to give the reader an opportunity of judging for himself, what is the precise extent of the claim, which the patrons of Mayow’s reputation may fairly set up. It is also, of the more importance in a history of this subject, to notice the pretensions of this writer, as it appears that Boyle’s experiments on artificial air, in his physico-mechanical experiments were not made until the year 1767 et seq. Though the first edition of that treatise repeatedly quoted by Mayow was in 1661. Mayow’s experiments therefore ought to have been, and probably were known to Boyle at the publication of his last edition.[43]
[42] I believe Dr. Beddoes gives no more than the heads of each chapter and, a brief analysis of the contents. Dr. Beddoes in his remarks on Fourcroy’s account of Mayow, Ann. de Chimie. No. 85, Nich. Jour. v. 3 quarto p. 108 states Mayow at the time of his death to have been only 27 and 28: but he was born in 1645 and died in 1769. Biog. Dict. 8vo. ed. of 1798.
[43] I do not find that Boyle quotes Mayow, though their labours in the same field were contemporary. But Boyle in his hidden qualities of the air published in 1674 has an observation that looks as if derived from Mayow. “And this undestroyed springiness of the air, with the necessity of fresh air to the life of hot animals, suggests a great suspicion of some vital substance if I may so call it, diffused through the air, whether it be a volatile nitre or rather some anonymous substance, sidereal or subterraneal, though not improperly of kin to that which seems so necessary to the maintenance of other flames.”
The following is an analysis of Mayow’s essays, so far as relates to his chemical Philosophy.