would require 5':; full pails of fresh air each minute, or a total of 7,680 pails 

 each twenty-four hours. 



This amount of fresh air would contain 3 pails of carbon dioxide; after the 

 cow breathed the air it would contain 307 '/a pails of carbon dioxide; and 

 almost a pail of water would be given off by the cow through her lungs and 

 pores. 



A cow consumes TWICE the WEIGHT of pure air that she does of 



FOOD AND WATER COMBINED. 



Can you realize what an amount that is? 



Pile up a day's ration of hay and silage and grain; beside it put the pails 

 of water a cow will usually drink in a day. 



The WEIGHT of that food and water equals just about ONE-HALF 

 the WEIGHT of the air the cow requires during the twenty-four hours. And 

 that is figured on the basis of pure, fresh air at that. 



To phrase it in another way : 



The average cow requires for six months' rations about 2.\'i tons rough 

 feed, 3'/2 t^oris silage, 1 ton concentrates and 131/2 tons water, a total of 

 201/2 tons, or 41,000 lbs. 



For the same period, the cow requires 82,000 lbs. of air, or 4 1 tons. 



The 2OJ/2 tons of feed each, above mentioned, for 20 cows would fill 

 40,000 cu. ft., or the loft of a barn 36 ft. x 60 ft. with 14-ft. side posts and 

 gambrel roof. 



The 41 tons of air each for 20 cows would fill the loft of such a barn 

 36 ft. wide with 14-ft. side posts and gambrel roof, 10 miles long. 



The scientists tell us that air is not a simple substance, but consists of a 

 mechanical mixture of the gases oxygen and nitrogen with about 1 per cent by 

 volume of argon. Atmospheric air of ordinary purity almost always contains 

 a little carbon dioxide together with more or less vapor of water, and a very 

 active form of oxygen known as ozone. The average composition of air is 

 given as follows: 



Oxygen 20.588 



Nitrogen 76.765 



Carbon Dioxide 0.039 



Water 1-686 



Argon and other constituents 0.922 



100.00 



The air as thrown off by the lungs at 90 to 98 degrees Fahr. is nearly 

 saturated with water, and contains from 3 to 5 per cent carbon dioxide; hence, 

 it is from 1 to 3 per cent lighter than the air inhaled. 



