I^EW York Agricultural Experimea^t Station. 63 



is carefully controlled the most important disturbing factors are 

 her health, length of the interval between lactation periods and 

 her age. These difficulties in obtaining an accurate measure of 

 the influence of machine milking can be best met by studying the 

 efl^ect on ar number of cows for several years, arranging the de- 

 tails so as to neutralize the disturbing factors so far as possible. 



THE MILKI^^G MACHINE. 



The Burrell-Lawrence-Kennedy milking machine arranged for 

 milking two cows simultaneously, as it appeared during the latter 

 portion of these experiments, is shown in Plate I. Its most im- 

 portant elements are the portions within which the milking is 

 actually done — the funnel-shaped teat cups which surround and 

 support the teats. These are shown in the illustration, supported 

 by the handle of the pulsator in a manner convenient for carrying 

 about the stable. The large upper ends of the teat cups are pro- 

 vided with rubber curtains which prevent the entrance of air 

 at that point when the cups are on the teats. The small lower 

 ends are connected with the pail by rubber tubes. The vacuum 

 within the pail is transmitted through these tubes to the teat 

 cups and the milk as it comes from the teats flows through these 

 tubes to the pail. A vacuum of approximately one-half an 

 atmosphere is maintained in a reservoir by an air pump and this 

 reservoir is connected with the pail by suitable piping. 



When th(? milking machine has been connected with this 

 vacuum reservoir and placed in operation a mechanism on the 

 cover of the pail automatically interrupts the connection between 

 the vacuum reservoir and the teat cups about once per second, 

 the exact rate being under the control of the operator. During 

 the brief period in which the vacuum acts upon the teat the 

 muscle at the end of the teat relaxes and the milk in the teat 

 flows out into the tube at the base of the teat cup. During the 

 alternate periods in which the vacuum is interrupted the opening 

 at the end of the teat closes and the teat refills from the milk 

 cistern above it. 



