MAYOW'S DISCOVERIES. 419 



From the above observations it appears probable, that the Thunder 

 , , , , , , /. . ' . , . , storms, &c. 



sound of thunder, and the formation of ram dunng a thun- 

 der storm, are caused by the explosion of volumes of hy- 

 drogenous and oxigenous gases fired by the lightning-; and 

 I am not aware of any phenomenon attending a thunder 

 storm, but what may be easily accounted for upon the same 

 theory. 



IX. 



Farther Communication from E. D. respecting the Discoveries 

 of Mayow. 



To Mr. NICHOLSON. 

 SIR, 



I 



FORWARDED to you, a few days ago, some additional 

 remarks on Lavoisier's claims, and stated some opinions of 

 Mayow's concerning acidification. On looking again into that 

 author, I have met with such further facts as I thought might 

 be welcome to you, and request, Sir, that you will make such 

 use of them as you think fit. 



I am, Sir, 



Your obedient servant, 



E. D. 



Speaking of the generation of nitrous acid, Mayow says : Mayow's in- 



" Ut autem intelligatur, quo ritu spiritus acidus nitri in terra "'^^^/o'^.' that 

 ° ' ^ *■ sulphuric acid 



" generatuf, Hceat non nulla de spiritu sulphurisy caeterisque is formed by 

 " liquoribus acidis proemittere : quippe spiritibus acidis qui- °^g'*^^j^" ^''^^ 

 " buscunque similitudo maxima, et affinitas intercedit," — 

 Tractat. quinq. p. 32. 



He then combats the notion of the acidity of vitriol arising That the acid i 

 from an acid salt contained in the sulphur, and thinks the acid "J^!" ^^^ ®"^' 

 spirit may be formed during the deflagration of sulphur, from 

 the mutual action of the sulphureous particles of the deflagra- 

 ting matter, and the nitro-aerial particles of the air ; which ac- 

 tion he considered, however, to be of a mechanical nature. 

 Ibid. p. 34. In support of these opinions, he refers to some 

 circQmstances occurring in the distillation of oil of vitriol, where 

 he has these words: " Quippe experientid constat, quod, si 

 ^* distillatio vitrioli per decern, aut etiam plures dies cum igne 

 H h h2 " maximc 



