'294: ATMOSPHERICAL PRESSURE 



over head in water, will be found upon the 

 average to be nearly .9 the weight of an equal 

 bulk of water. 



r- It is remarkable that all the component parts 

 of the animal frame, at least of the human sub- 

 ject, are severally specifically heavier than the 

 whole body, with the exception of air. — Bone, 

 muscular flesh, blood, membrane, &c. are all 

 heavier than water: animal fat is perhaps the 

 lightest of the components, but even this is 

 heavier specifically than the whole man upon the 

 average. — Bone from the leg of a calf I found 

 to be 1.24 specific gravity. The lean of beef 

 (raw) I found 1.045 specific gravity. — Blood is 

 from 1.03 to 1.05 specific gravity according to 

 circumstances : — on the whole, the solid and 

 liquid parts of the body, examined after life is 

 extinct, would appear on an average to be some- 

 where about 5 per cent heavier than water. 



That part of the volume of man which is 

 exclusively occupied by air, and which may 

 therefore be considered as adding nothing mate- 

 rial to the weight of the body, consists of the 

 air tubes and air cells of the lungs, the trachea 

 or wind-pipe, the mouth and other appendages. 

 It is not easy to ascertain the medium volume of 

 air in the lungs of any individual, Messrs. Allen 



