222 AGRICULTURE OF MAINE. 



have baffled agricultural inventors. The nervous, sensitive dis- 

 position of the individual cows, together with the lack of uni- 

 formity in the form and size of the udder and teat, has made 

 it very difficult to invent a machine which would milk different 

 cows satisfactorily. 



The idea of milking by machinery is not new. IMany types of 

 machines have been tried and pronounced worthless. Accord- 

 ingly the question is being asked, "Are the machines at present 

 on the market a success?" Manifestly there is no specific 

 answer to such a general question. Automobiles are generally 

 considered a success though many find them both troublesome 

 and expensive and there are wide differences in quality among 

 the various makes. It is probable that the different milking 

 machines on the market are likewise of unequal efficiency. 



All milking machines fall into one of two general classes. 

 ( I ) Those which mechanically force the milk from the teat 

 after the manner of hand milking. (2) Those which depend 

 on the action of a vacuum producing an effect similar to that 

 of the mouth of the calf. 



While it is possible that some representatives of the teat com- 

 pressing milkers are in use in this country all of the tests of 

 milking machines thus far reported, with the exception of those 

 of the "Murchland" and "Thistle" at Guelph. have been made 

 with machines having the action of the mouth of the sucking 

 calf. The calf takes hold of the teat and by contracting the 

 muscles of the mouth draws the milk from the teat. This re- 

 sult is caused by the removal of air in the calf's mouth, or, in 

 other words, the creation of a vacuum. On account of outside 

 pressure the milk from the udder is forced into the empty 

 mouth. When the milk flows into the mouth the calf swallows, 

 thus giving relief to the teat. The operation of the milking 

 machine is based on practically this same principle. A vacuum 

 is formed by ejecting the air from a large pail which is con- 

 nected to the teats of the udder by rubber tubes having mouth- 

 piece attachments at the ends. The milk is forced from the 

 udder to replace the air drawn from the pail and the piston in- 

 termittently cuts off the connection between the vacuum and the 

 teat, thus .momentarily relieving the air suction from the latter. 



There are three main parts to the milking plant, namely, an 

 appliance for producing vacuum, or both vacuum and pressure. 



