A HARD-WORKING DIET. 447 



Ibs. ozs. grs. 



2. Carbon, a solid, occurs nearly pure in charcoal. 



The carbon in the body is variously combined 

 with other elements, and by its burning sets 

 free heat, and produces carbonic acid gas .. 18 n 50 



3. Hydrogen, a gas, and the lightest substance 



known. It occurs mainly in water ; the 

 quantity in the human body would fill a space 

 of some 2690 cubic feet, and would weigh 

 about .. .. .. .. .. .. 14 3 150 



4. Nitrogen, a gas without energetic properties. 



It is an essential part of all bones and blood 

 and muscle. The quantity in the body 

 would occupy about 66 feet cubic, and would 

 weigh about .. .. .. .. .. 4 14 o 



$. Phosphorus, a solid. It occurs specially in 

 various compounds of the bones and of the 

 brain. It burns so readily in air that it is 

 here kept in water. In the human body we 

 find about I 12 25 



6. Sulphur, a yellow combustible solid, often 



called called brimstone. Like all the pre- 

 ceding elements, it is found in all the tissues 

 and secretions of the body, but always in 

 combination. It amounts to .. .. 08 o 



7. Chlorine, a greenish-yellow gas found in the 



body chiefly with sodium, the compound 

 being common salt. The chlorine in the 

 human body would fill a space of 2 cubic feet 

 and 510 cubic inches, and would weigh .. 04 150 



8. Fluorine, hardly known in the separate state, 



but probably a gas. It is found united with 

 calcium in the bones and the teeth. The 

 quantity in the body would fill a space 

 2 cubic feet and 150 cubic inches. It would 

 weigh .. .. .. .. .. .. o 3 300 



9. Silicon, a solid occurring in union with oxygen 



in hair, bones, blood, bile, saliva and skin.. o o 14 



10. Calcium, a metal, the basis of lime. It occurs 



chiefly in bones and teeth .. .. .. 3 13 190 



11. Potassium, a metal, the basis of potash. It is 



lighter than water, and when placed on it 



