Saltpetre from Nitre beds, should not have known, or have noticed the five treatises of Mayow on chemical, phisiological and pathological subjects, published a century preceding. Mayow is quoted by Hales,[36] by Lemery,[37] and by Brownrigg,[38] but though they appear to have read his work, it is evident that they knew not how to appreciate, or to profit by it. Haller[39] also refers to him, and he is respectfully quoted by Blumenbach[40]: but his book nevertheless long remained in comparative obscurity. From their time Mayow has been neglected until his writings were noticed by Dr. Forster, in 1780,[41] and again announced as almost a discovery in the chemical world, by Dr. Beddoes in the year 1790. His doctrines touch so nearly on the subsequent discoveries of Priestley, Scheele, Lavoisier, Crawford, Goodwin, &c. that it seems absolutely necessary to discuss his pretensions, before those of his successors can be accurately admitted. As I am acquainted with Dr. Beddoes’s pamphlet on Mayow, from the analytical review of it only, (V. vi.) and have no opportunity here of consulting it, I shall take up Mayow’s book, and give an account of his tenets, from the work itself. [33] In the beginning of his first vol. of experiments: it is an abridgment of Sir J. Pringle’s discourse. [34] Discourses p. 4. [35] Martyn’s abridgment of the Philosophical transactions v. 9. p. 396. I think Maud’s experiment in 1736 likely to have suggested those of Mr. Cavendish in 1766. [36] Vegetable Statics v. 2. p. 234. [37] Mem. de l’Acad. Royale 1717 p. 48. On ne dit pourtant point trop sous quelle forme ce nitre se contient dans l’air, et Mayou, Auteur Anglois et grand defenseur du Nitre-Aèrien voulant èclaircir cette difficultè, suppose l’air impregnè par tout d’une espece de nitre metaphysique, qui ne merite pas trop d’ètre refutè, quoi-qu’il l’àit cependant ètè suffisamment par Barchusen et par Schelhamer. Le fondement de l’opinion du Nitre aèrien, c’est comme le rapporte Mayou lui mème, qu’apres avoir enlevè à une terre tout le Nitre qu’elle contenoit, si on l’expose ensuite à l’air pendant un certain tems elle en reprend de nouveau: il est vrai que si l’observation ètoit parfaitement telle qu’elle vient d’ètre rapportèe, on auroit une plus grande raison qu’on n’en a, de supposer dans l’air une très-grande quantite de nitre, et de mettre sur le compte de ce nitre aèrien un grand nombre d’effets auquels il n’a certainement aucune part. The experiment of Lemery mentioned in Dr. Watson’s Essay on Nitre, is in p. 54 of the Mem. de l’acad. royale for 1717 not for 1731.