296 ATMOSPHERICAL PRESSURE 



or discussed I am not aware ; but I presume no 

 one lias succeeded in determining either the 

 nature or the quantity of the air so enveloped in 

 the system. We shall now examine how far 

 jljich a notion is countenanced by the preceding 

 statement of facts. 



According to the preceding table of Robertson 

 the average bulk of the ten men was 2.618 cubic 

 feet = 4500 cubic inches nearly ; but of this 

 volume 150 inches according to the above esti- 

 mate were air, and the remainder 4350 inches 

 were solid and liquid parts of the body. Now 

 the average specific gravity of those parts of the 

 body has been estimated above at 1.05 when 

 examined as dead matter : this would make their 

 weight equal to 4567 cubic inches of water ; 

 whereas it was found by actual weighing to be 

 1461bs. as per table = 4044 cubic inches; hence 

 the observed weight was less than the calculated 

 weight, a portion equal to the weight of 523 

 cubic inches of water, or more than l-9th of the 

 whole weight of the body. 



Here is a discrepance that demands an inves- 

 tigation. Can Robertson's table of the specific 

 gravities of men give too low an estimate ? This 

 is not likely ; every one knows that the human 

 subject generally floats in water till the lungs 



