THE OLDER METHODS OF CREAM-RAISING. 113 



away from under the cream. For many reasons the former method 

 is to be preferred. 



50. The Swartz Method of Cream-raising. This method, devised 

 in 18G3 by Gustav Swartz, of Hofgaarden, near Wadstena, in Sweden, 

 requires an area of creaming space per cow of as much as half a 

 square metre, so that there is an excessive demand for creaming 

 space. It is directed in this method that the milk be poured into 

 special vessels, known as the Swartz milk-pans. These are long 

 four-cornered tin vessels, with rounded edges 50 centimetres high, 

 and of a capacity of 36 to 50 litres. The milk is poured in to a 

 depth of 40 centimetres. The milk-pans when thus filled are placed 

 in a long square receptacle, which is made of sufficient size to hold 

 at least six or at most ten cans. They are then packed with ice 

 and left standing from 12 to at longest 24 hours. During this time 

 the milk is cooled down to within a few degrees of freezing point. 

 Swartz recommended that the sweet cream should be immediately 

 churned, and he thus gave an impetus in Sweden and Denmark 

 to the first attempt to introduce sweet-cream churning on a large 

 scale, and to place upon the world's market sweet-cream butter 

 (fresh butter) as a keeping butter. 



4s soon as the warm milk is placed in ice all vertical currents 

 cease, since cooling takes place chiefly on the bottom and sides of the 

 milk-cans, and not from above. Only currents flowing in almost a 

 horizontal direction, from the outside to the inside and vice versa, 

 take place, which, so long as the milk-can is not broader than say 16 

 to 20 centimetres, do not to any extent hinder the fatty globules in 

 their ascent to the surface. According to the author's observations, 

 warm milk when placed in ice in Swartz milk-pails requires from 

 three to four hours to cool down to about 10 C. It stands, therefore, 

 for several hours at temperatures at which the opposition offered to 

 the movement of the fatty globules is comparatively slight. This, 

 and the complete absence of vertical currents, are the causes why 

 more fatty globules rise into the cream-layer in the Swartz method, 

 during the first hours of cream-raising, than in any other older 

 methods of cream-raising. Even after 12 hours the yield of cream 

 in the Swartz method is almost always greater than in the Holstein 

 method under similar conditions. As soon as the temperature of 

 the milk falls below 10 C., the opposition in the milk-serum rapidly 

 increases, and impedes the motion of the fatty globules to the 

 surface more and more with the lapse of time. After 24 hours the 



( M 175 ) H 



