relatifej&ltfdi^fygtji and Cavendish. 505 



just and splendid a^geiii^msation, running parallel to the 

 whole range of chemical induction on all those subjects which 

 occupied the succeeding century, it is impossible not to allow 

 that this young man handed down a bright light to all who fol- 

 lowed him *| and made more of a few facts, than the greater 

 part of the next generation did of many. 



Mayow also examined the two kinds of air which Boyle 

 had obtained by the action of the nitric and vitriolic acids on 

 iron, and observed the permanence of the one gas and the 

 partial condensation of the other. To determine whether they 

 resembled common air in containing any of the nitro-aertal 

 aura, he added them to air in which a mouse was confined, 

 and inferred that they do not, from their not prolonging the 

 animal's life. He then examined their relative elasticity, and 

 finding in them the same capacities of compression and ex- 

 pansion as in common air, he decided that there exist va- 

 rious elastic fluids, and held with Newton that these, as well 

 as that aura which he deemed pre-eminently elastic, and the 

 residual gas from which it is abstracted by respiration, owe 

 their different degrees of elasticity and permanence to ele- 

 mentary differences in their particles, and in the substances 

 from which they are derived f. 



The only philosopher, as far as I am aware, who dissented 

 from these views, was the elder Bernoulli, having detailed 

 his own respecting fixed air J, " Mayow," he said, " after 



to the combination of these nitro-aerial particles with the blood, and the 

 increased heat in exercise to a greater number being breathed in the same 

 time. In like manner he accounts for febrile heat, for acid in the blood and 

 urine, for the digestion of the food, and for muscular contraction. 



* Mayow's work, besides its publication in England, was at least twice 

 reprinted abroad ; a detailed account of it was given in the Philosophical 

 Transactions. It was repeatedly quoted by Hales, whose book was in 

 every chemist's hands, and by other authors : it was therefore sufficiently 

 known to have produced a real influence on the minds of men. 



t De Spir. Nit. cap. 9. p. 163. — " Utrum aer de novo generari possit?" 

 — In his account of Boyle's gases he says — "Aura praedicta haud minori 

 vi elastica quam aer vulgaris donatur prout sequenti experimento mihi 

 compertum est." "imili ratione experimentum feci, num aer in quo ani- 

 mal, aut lucerna expirassent, aeque ac aer inviolatus, vi elastica pollent; et 

 quidem mihi videtur aer iste haud minus quam aer quivis alius se expan- 

 dere." '* quanquam aura ista in qua animal aut lucerna expirarunt vi 

 elastica aeque ac aer inviolatus pollet, et tamen eadem particulis nitro-aereis 

 vitalibusque destituitur." " Hie etiam referre possumus quod in cap. sup. 

 4e aura hujusmodi aerisque vulgaris differentia annotavimus, et tamen 

 verisimile est aura; istiusmodi cum aere vulgari magnam affinitatem inter- 

 cedes, vimque elasticam eorum utrorumque a causa haud multum diversa 

 provenire. Etenim cum ferrtim e particulis rigidis, item spiritus corrosivi e 

 particulis nitro-aereis summe elasticis constant, aura ex iis utrisque invicem 

 fervescentibus conflata ab aere vulgari haud multum diversa erit." 



% " Allata experimenta satis, ni fallor, ostendunt existentiam aeris in cor- 

 Phil. Mag. S. 3. No. 190. Suppl. Vol. 28. 2 M 



