i 





Hid 







106 



9 



Analyfa of the Air. 



ftrongeft veflels 5 and from the vaft explore 

 force with which the air generated f rom 

 nitre in the firing of gun-powder, willburft 

 afunder the ftrongeft bombs or cannon, and 

 whirl fortifications into the air. 



This fort of mercurial gage, made ufe of 

 in Experiment 89, with fome unftuous mat- 

 ter, as Honey, Treacle, or the like, on the 

 Mercury in the tube, to note how high it 

 rifes there, might probably be of fervice 

 in rinding out unfathomable depths of the 

 Sea, viz. by fixing this fea-gage to fome 

 buoyant body which fhould be funk by a 

 weight fixt to it, which weight might by 

 an eafie contrivance be detached from the 

 buoyant body, as foon as it touched the bot- 

 tom of the fea 5 fo that the buoyant body 

 and gage would immediately afcend to the 

 furfacc of rhe water ; the buoyant body 

 ought to be pretty large, and much lighter 

 than the water, that by its grearcr eminence 

 above the water it might the better be feen ; 

 For 'tis probable that from great depths it 

 may rife at a conftderable difhnce from the 

 fhip, tho' in a calm. 



For greater accuracy it will be needful, 

 firft to try this fea-gage, at fcveral different 



depths, 





if 











