I estimate that it takes from 15 to 18 lbs. of ordinary hay per day to run this cow-machine, which we have been talking about, even when kept warm and comfortable; and if exposed to cold storms, probably not less than 20 lbs. of hay a day, or its equivalent, and this merely to keep the machine running, without doing any work. It requires this to keep the cow alive, and to prevent her losing flesh. If not supplied with the requisite amount of food for this purpose, she will take enough fat and flesh from her own body to make up the deficiency; and if she cannot get it, the machine will stop--in other words, the cow will die. We have, then, a machine that costs say $100; that will last on an average eight years; that requires careful management; that must have constant watching, or it will be liable to get out of order, and that requires, merely to keep it running, say 20 lbs. of hay per day. Now, what do we get in return? If we furnish only 20 lbs. of hay per day we get--_nothing_ except manure. If we furnish 25 lbs. of hay per day, or its equivalent, we get, say half a pound of cheese per day. If we furnish 30 lbs. we get one pound of cheese per day, or 365 lbs. a year. We may not get the one pound of cheese every day in the year; sometimes the cow, instead of giving milk, is furnishing food for her embryo calf, or storing up fat and flesh; and this fat and flesh will be used by and by to produce milk. But it all comes from the food eaten by the cow; and is equal to one pound of cheese per day for 30 lbs. of hay or its equivalent consumed; 20 lbs. of hay gives us nothing; 25 lbs. of hay gives us half a pound of cheese, or 40 lbs. of cheese from one ton of hay; 30 lbs. gives us one pound, or 66⅔ lbs. of cheese from one ton of hay; 35 lbs. gives us 1½ lbs., or 85 5/7 lbs. of cheese to one ton of hay; 40 lbs. gives us 2 lbs. of cheese, or 100 lbs. of cheese from one ton of hay; 45 lbs. gives us 2⅓ lbs. of cheese, or 111 lbs. of cheese from one ton of hay; 50 lbs. gives us 3 lbs. of cheese, or 120 lbs. of cheese from one ton of hay.