232 MELTING POINT OF BUTTEE. 



me, has varied from 93° to 98°, from different herds 

 at the same season of the year. 



Experiment XII. 



No. Iherd 98° 



No. 2 " 96° 



No. 3 " 94° 



No.4 " 93° 



In order to obtain the melting point of butter, the 

 best process that I have yet found, is by the use of 

 mercury. Heat a small plant-pot of sand to about 

 120°, and set in the sand a small cup of mercury, 

 Tvith the bulb of a thermometer immersed therein, 

 and supported by a cross-bar. Having previously 

 filled a section of a quill or a cylinder of paper, open 

 at both ends, with butter, impale on a needle so that 

 the point of the needle shall extend through a quar- 

 ter of an inch. By immersing the quill or cylinder 

 in the mercury, the projecting needle keeps the ap- 

 paratus always at the same distance below the sur- 

 face of the mercury, and the butter enclosed in the 

 cylinder is subject to a uniform pressure of say three 

 eighths of an inch of mercury. The moment the melt- 

 ing point of the butter is reached, the warm mercury 

 forces it out ; it immediately jumps to the surface, 

 and at the same instant the observer reads off the 

 height of the immersed thermometer. 



Of the three breeds we are considering, the Ameri- 

 can Holsteiu presents the smallest globule to its milk. 

 The globules are more uniform in their size than in 

 the Ayrshire milk, and there are fewer granules. 



