Page:Popular Science Monthly Volume 45.djvu/253

Rh centrifugal force. A strong steel bowl is made to rotate by hand-power or steam, at a speed of five to eight thousand revolutions per minute; by this means the heavier portion of the milk, the skim milk, is separated from the lighter portion, the cream, and both are collected in separate vessels.

The work in the creamery room includes the handling and care of the cream previous to churning, the churning, and the working and packing of the butter. In the cheese room, where there are eight milk vats, each of a capacity of three hundred pounds, thirty-two students may work at the same time; the various steps in cheese-making, from the proper handling of the milk to the curing of the cheese, are here learned.

A most important part of the instruction is the milk testing, which is taught in the laboratory. Farmers' boys, who previously to their entering the school knew nothing whatever about the different components of milk, here learn to determine the percentage of fat in milk, skim milk, buttermilk, whey, and cream, with almost as great accuracy as any experienced chemist, and certainly as satisfactorily for all practical purposes. This has been made possible by the introduction of the Babcock test for the determination of fat in milk, a method invented nearly four years ago by Dr. S. M. Babcock, chief chemist to the Wisconsin Experiment Station. The method has won for its originator a worldwide reputation and the gratitude of progressive dairy farmers in this and other countries. The test, which was given to the public without any restriction of patent, is extremely simple, and may be made on a farm or in a creamery or cheese factory as well as in a chemical laboratory, everywhere with equal correctness and facility. In the dairy school the percentage of fat in milk is determined by Babcock's test, and by a combination of the test and the lactometer (a simple apparatus to determine the specific gravity of milk or its weight in relation to water), adulteration of the milk, and the extent of the same may be detected.

The course of the dairy school lasts three months—viz., January to March, inclusive. The expenses of the school while in operation are very heavy; the milk bill alone thus amounts to eighty dollars a day during this time. In addition to this course, dairy certificates are issued to such graduates of the school as have shown proficiency in the operation of a creamery or a cheese factory for one or more seasons; candidates for such certificates must send in reports of their work once a month to the dean of the college; their factories are further inspected by an instructor of the school, to ascertain whether or not the candidate may be granted a certificate, and thereby given the recommendation of the State Dairy School as a successful butter or cheese maker.