Analyfis of the Air. ijp 



as the putting of fulphureous mixtures into 

 the liquor, 'tis plain, thofe fleams can eafily 

 penetrate the wood of the containing vef- 

 fels. No wonder then, that the more fub- 

 tilc lightning fhould have the like effeft. I 

 know not whether the common practice of 

 laying a bar of iron on a veffel, be a good 

 prefervativeagainft the ill effe&s of lightning 

 on liquors I fhould think that the covering 

 a veflel with a large cloth dipped in a ftrong 

 brine, would be a better prefervative 5 for 

 falts are known to be ftrong attra&ers of 

 fulphur. 



The certain death which comes on the ex- 

 plofion of Mines, feems to be effe&ed in 

 the fame manner : For tho' at firft there is 

 a great expanfion of the air, which muft 

 dilate the lungs, yet that air is no fooner 

 filled with fuliginous vapours, but a good 

 deal of its elafticity is immediately deftroyed : 

 As in the cafe of burning Matches in Ex- 

 periment 103, the heat of the flame at firft 

 expanded the air ; but notwithftanding the 

 flame continued burning, it immediately 

 contra&ed, and loft much of its elafticity, 

 as foon as fome quantity of fulphureous 

 fleams afcended in it. 



S a Which 



