Anahfis of the Air. 2 op 



preffes and confines this air in the Apples, 

 mdft be equal to the weight of 48 of our 

 atmofpheres, when the Mercury in the Ba- 

 rometer ftands at fair, that is 30 inches high, 

 Now a cubick inch of Mercury weigh- 

 ing 3580 grains, thirty cubick inches (which 

 is equal to the weight of our atmofphereon 

 an area of a cubick inch) will weigh 1 5 

 pounds, 5 ounces, 215 grains; and 48 of 

 them will weigh above 736 pounds 5 which 

 is therefore equal to the force with which an 

 inch fquare of the furface of the Apple 

 would comprefs the air, fuppofing there 

 were no other fubftance but air in the Ap- 

 ple : And if we take the furface of an Ap- 

 ple at 16 fquare inches, then the whole 

 force with which that furface would com- 

 prefs the included air, would be 1 1 776 pounds. 

 And fince a&ion and re-a&ion are equal, this 

 would be the force, with which the air in, 

 the Apple would endeavour to expand it felf, 

 if it were there in an elaftick and ftrongly 

 comprefied ftate : But fo great an expanfive 

 force in an Apple would certainly rend the 

 fubftance of it with a ftrong explofion, efr 

 pecially when that force was increafed, by 

 the vigorous influence of the Sun's warmth, 



P We 



