688 CATTLE AND DAIRY FARMING. 



prevent evaporation. The position of the scale is then read off, that part being read off 

 which coincides with the middle part of the deepest curved line on the surface of the 

 liquid. The temperature during the estimation of the specific gravity of the solution 

 must be noticed, and if it is 17°. 5 C. the specific gravity will need no farther correc- 

 tion, for it must be understood that it is diminished by a higher and increased by a 

 lower temperature. The temperature of the water in A may fluctuate from 16°.5 to 

 18°.5 C, and the snecific gravity of the ethereal solution at n°.5 C. having been found, 

 the amount of fat in weight per cent, can be obtained from the table supplied with the 

 instrument. The value of the Soxhlet apparatus is that the percentage of fat to the 

 second decimal place is obtained, thus making it as valuable as actual analysis. 



CREAM-SEPARATING MACHINES. 



REPORT PREPARED FOR CONSUL BHAW, OF MANGBESTER, BY MB,. JAMES LONG, OF 



BETCHIN, ENGLAND. 



Up to the present time the most popular machine in England and France has been 

 the De Laval, which is the only one that has been regularly exhibited. There are two 

 reasons for its popularity — its price, which has varied between £30 and £37, and ils 

 value — for it is a good machine. Perhaps it also ought to be said that it has no opposi- 

 tion in either country, for this is almost the fact. True, three other machines have 

 been exhibited in England; butiu one case, the "Danish," patent difficulties have pre- 

 vented its sale; in another, the "Lefeldt," is very much more expensive; and in the 

 third, the "Petersen," a quite new machine, which competed at the Royal last year 

 against the Laval for a gold medal. It was far higher in price, suitable only for big 

 dairies and factories, and did not take off all the cream. There is, however, a difficulty 

 with the Laval, which its inventor can not overcome; it requires a great deal of power 

 for so small a machine, and it cannot be made in smaller or larger sizes, these being 

 most insuperable objections when rival machines are introduced without them. 



The De Laval is the invention of a Swede of that name, but it is not the earliest in- 

 vention, for centrifugal force, which is in reality forced gravitation, as applied by an 

 English inventor, was first used by a German, Professor Fuch, as early as 1859. In 

 Laval's machine the receiver revolves with the milk some 5,000 times a minute and 

 takes the cream from some 200 quarts an hour. This receiver, which is made of steel, 

 works upon a vertical axis, and is filled with the milk through the medium of a funnel 

 which passes into it from above. As the milk revolves, the centrifugal action causes 

 the lighter cream to gather at the top in the center, while the heaver portion of the 

 volume is forced to the outside. This being the case it only needs some additional out- 

 side power to force it outside and this is provided by the continual stream of new milk. 

 The result is that the heavy skim milk is compelled to find its way through a tube to 

 an outer chamber whence it runs out by a pipe. As the new milk enters and is skimmed 

 the enlarged volume of cream likewise demands an outlet, for it cannot get to the per- 



hery nor escape with the milk; hence it is provided with a special tube and chamber, 

 nd escapes from another portion of the machine in a similar way. As the drum is 

 11 meters in diameter, the surface speed of the interior required to separate the cream 

 is about 15,000 feet per minute. 



Now we will take the Danish machine, originally so called,, although now that there 

 are not one but four or five machines made in Denmark, we ought to follow the example 

 of the Danes themselves and use the names of the makers; otherwise buyers will some 

 day get into a difficulty. This machine, called, respectively, the Petersen and Burmeis- 

 per'&Dam, is sent out by H. C. Petersen & Co., Copenhagen, which i'act should he 

 specially noted, as of the eight machines we know four are made by different firms of 

 this name. So far, this is without doubt the best machine which has yet appeared. It 

 ts an open, flat-topped, horizontal drum, which must be fixed upon a solid foundation 

 and can be worked by one or two horses or by steam power. The drum is about SJ 

 feet in diameter, or 15 inches across the open space, while the depth is 2 feet. In the 

 center is a cone, within which is the shaft by which the machine is worked. On the top 

 or ledge of the outside drum is an apparatus invented by Professor Fjord, of Copenhagen, 

 and into this the milk runs as it comes from the vat; here are a set of strainers, and in 

 each corner tubes so arranged that just as much milk can be passed through as is neces- 

 sary. Each tube extends to very nearly the floor of the drum; it is bent at the end so 

 that as the milk leaves it it runs directly onto the periphery. When the drum is in 

 motion— and it revolves only 1,800 times a minute— the body of the milk is whirled 

 yound, and immediately becomes a wall Unin gthe per iphery of tfte drum. As ip Ih 



