440 Transactions of the American Institute. 



in 1835 Asahel Baker of Windsor, in tlie same State patented apian 

 of propelling cluirns by weights ; a principle that has since been 

 embodied in quite a number of churning machines, but which, 

 no matter how ingeniously applied, is, in practice, not worth 

 a cent. The destruction of the patent office,* as above alluded to, 

 has left us in the dark as to the precise nature of most or all 

 of these apparatus. It is likely, however, that their most important 

 features have since been re-invented and applied in many different 

 ways. This is especially true with regard to the atmospheric process,-, 

 the most important of all modern improvements in the churn, as will 

 naturally be inferred from what has already been said concerning 

 the admission of air to the cream while being churned. All efficient 

 forms of atmospheric churns have combined some device for forcing 

 the air into the cream, with some variety of dasher, either rotary or 

 otherwise. Some six years ago a claim was allowed on certain devices 

 for churning by the use of air alone, which it was proposed to carry 

 into practice as follows : A stationary bellows forced a current of air 

 through a flexible tube furnished with a nozzle at the end. This 

 nozzle was inserted below the surface of the milk, contained in a 

 suitable vessel, and the agitation caused by the air-blast was pre- 

 sumed to be capable to bring the butter. About the same time or a 

 little latter, another churning apparatus with a forcible air-blast was 

 brought out, but this was used in connection with beating mechanism. 

 A double acting bellows, driven by a crank and pitman, was employed 

 to force the air into a hollow shaft arranged centrally within the 

 churn. This shaft carries the beaters, which were formed with 

 numerous small holes, through which the air passed fi-om the shaft 

 into the cream. We do not consider either of these plans of much 

 consequence. An atmospheric churn without beaters or dasher will 

 churn very slowly, and will not be able to gather the butter, while 

 one that has beaters and is properly constructed will force air enough 

 into the cream without bellows or blowing machinery. 



The essential feature in a good churn is capacity for giving a 

 steady and uniform agitation to its contents, and for doing this at 

 the most rapid rate possible without raising the tcm])erature of the 

 cream more than ten degrees in the process. Uniformity in the agi- 

 tation causes the butter globules to burst nearly all at the same time, 

 while the avoidance of undue heat insures a firm, liard texture to 

 the butter. These requisites are very well secured in several very 

 different kinds of churns : for instance, in the barrel churn in com- 



