Summer. Winter. Solid or margarine fat, 40 65 Liquid or oleine fat, 60 35 --- --- 100 100 Winter butter appears to be rich and fine in proportion as the oleine fat increases. The proportion is undoubtedly dependent on the food. A more general attention to the details of butter-making, and to the best modes of preserving its good qualities, would add many thousands of dollars to the aggregate profits of our American dairies. In the management of the dairy, an ice-house and a good quantity of ice for summer use are not only very convenient for regulating the temperature of the dairy-room, and for keeping butter at the proper consistence, and preserving it, but are also profitable in other respects. And now, when ice-houses are so easily constructed, and ice is so readily procured, no well-ordered dairy should be without a liberal supply of it. It is housed at a time when other farm-work is not pressing, and ponds are so distributed over the country that it may be generally procured without difficulty; but where ponds or streams are at too great a distance from the dairy-house, an artificial pond can be easily made, by damming up the outlet of some spring in the neighborhood. Where this is done, the utmost care should be taken to keep the water perfectly clean when the ice is forming. The ice-house should be above ground, and in a dry, airy place. The top of a dry knoll is better than a low, damp shade. The ice may be packed in tan, sawdust, shavings, or other non-conductors, and when wanted for use it should be taken off the top. CHAPTER IX. THE CHEESE-DAIRY. “Streams of new milk through flowing coolers stray, And snow-white curds abound, and wholesome whey.” Milk, if allowed to become sour, will eventually curdle, when the whey is easily separated; and this simple mode was probably the universal method of making cheese in ancient times. Cheese, as already explained, is made from caseine, an ingredient of milk held in solution by means of an alkali, which it requires the presence of an acid to neutralize. This, in modern manufacture, is artificially added to form the curd; but the acidity of milk, after standing, acts in the same manner to produce coägulation. This is due to the change of the milk-sugar into lactic acid.