SWINGING, CRADLE, AND ROCKING CHURNS. 



163 



the barrel moves, and rolls around an axle, or rocks, or makes both 

 these kinds of motion at once. They are generally made of wood, 

 occasionally of white-metal. Those that are in by far the most exten- 

 sive use are the swinging churns. The cradle churns, which were 

 formerly much used, are now almost entirely given up, and the 

 swinging churns are only found in small English and American 

 dairies. The nature of these churns necessitates the stopping of the 

 churning from time to time 

 to permit of the air in the 

 barrel becoming discharged. 

 For this reason, the opening 

 in the barrel is smaller than 

 is desirable in the interests 

 of cleanliness and airing, and 

 the extent of their motion 

 must not be allowed to ex- 

 ceed a certain limit. It is 

 not easy to introduce the 

 thermometer into the barrel. 

 These disadvantages, how- 

 ever, are more than compen- 

 sated for by the fact that 

 it is of all kinds of churns 

 the most easily set in motion 

 and maintained in motion, a 

 point of enormous import- 

 ance in churns for hand use. 

 In the case of good swinging 

 churns, the opening in the cask is wide, the taps of the bowls rest on 

 anti-friction-rollers, and the dashers, when such are present, are so 

 arranged that they can be easily taken out. Churns of this kind 

 made after the simplest pattern, as, for instance, the Lefeldt or 

 Victoria churns, are the best churns for hand use. The swinging 

 churns do not suit the conditions of large dairying. They cannot 

 be filled quite half-full, and require, according to their size, 30 to 

 100 revolutions per minute. 



There are a large number of different swinging churns. They are as 

 follows : 



(1) Those of common construction, in which the barrel is allowed to 

 revolve round a centre axle; (a) those with a wooden barrel, the churns 



Fig. 49. Diaphragm Churn. 



