88 Milk and Its Products 
Fjord’s control apparatus.—This apparatus, in- 
vented by the late Professor Fjord, of Denmark, 
estimates the fat by measuring the solidified cream. 
Glass tubes similar to those used in the oil-test 
churn are secured in a frame and a measured quan- 
tity of milk put in each. The frame holding the 
bottles is then whirled in a centrifugal separator 
frame till the cream is completely separated and 
brought together in a compact mass. This re- 
quires about forty-five minutes. The solid mass 
of cream is then measured with a scale and the 
fat estimated from it by means of a table con- 
structed by the inventor. This apparatus is in 
very common use in Denmark, but has never been 
introduced into this country. 
Development of milk tests in the United States.—Up 
to the year 1888, there had been no apparatus devised 
which would determine the fat in milk accurately, 
easily, cheaply and quickly. None of the methods 
described could in any sense supply the place of the 
gravimetric analysis, even for commercial purposes. 
The oil-test churn came the nearest to it, but that 
was of no use for milk, and at this time the separa- 
tor creamery was beginning to supplant the gathered- 
cream factory, and the demand was constantly 
stronger for a means of determining the fat in milk. 
This year also marked the establishment of the na- 
tional grant to Agricultural Experiment Stations in 
each of the states, and one of the first problems at- 
tacked by the chemists of these stations was to de- 
vise a quick method for the determination of fat in 
