282 SCIENCE AND PRACTICE OF DAIRYING. 



rated by the action of gravity into cream and skim-milk, which do 

 not subsequently admit of perfect admixture. On this account, un- 

 like wine, beer, and other beverages, it cannot be kept in the cellar 

 for a long time, nor is it suited for use on board ships, nor for trans- 

 marine export. This method of preserving milk is open to the objec- 

 tion that seven-eighths of the weight of the milk consists of water, and 

 on this account it can scarcely be described as possessing a valuable 

 economic property, which distinguishes articles used for transport. 

 It is not, therefore, suited for keeping for a long time, or for export 

 on a large scale. Condensed milk is better adapted for this purpose. 



A well-known apparatus for sterilizing large quantities of milk, in the 

 method above described, is* the sterilizing apparatus of Neuhausz, Gron- 

 wald, and Oehlmann (fig. 81), which is manufactured of four different 

 sizes for treating 50, 104, 150, and 238 bottles respectively 



132. Condensed Milk. The experiments and attempts which have 

 been made to convert milk by various methods into a condition 

 in which its most valuable and most essential properties may re- 

 main unchanged for a long time, if possible for years, date back to 

 the early part of the present century. Although the many and 

 various attempts which were made, up to the middle of this century, 

 were all failures, they cannot be regarded as valueless, since they 

 paved the way to the method in which the object aimed at can 

 alone be effected. In the first place, they have shown that milk, in 

 order that its usefulness for transport should be increased, and that 

 at the same time its keeping power be strengthened, must be deprived 

 of a portion of its water; and in the second place, that steaming the 

 milk in vacuum, at a temperature under 70 C., is necessary, and 

 that these are indispensable conditions to the utility and value of 

 the process. In the earliest attempts made in the United States of 

 America to change milk into an article which might admit of being 

 kept, the experiment was made of withdrawing all the water from 

 the milk, and of pressing the dry substance, to which small quan- 

 tities of bicarbonate of soda had been added, into cakes. Messrs. 

 Dalson, Blatchford, and Harris set up a manufactory about the year 

 1850, in the neighbourhood of New York, in which cakes of milk 

 were made according to the directions of E. N. Horsford. It was 

 believed that everything had been discovered and the desired object 

 attained. Lt was soon found, however, that the new preparation did 

 not come up to expectation. The milk cakes kept badly, as the fat 



