32 ANALYSIS AND ADULTERATIONS OF pUTTEE. 



filled with the fats to he tested, and after being labelled are 

 put aside to cool. A beaker is selected which fits sufficiently 

 closely into an opening in the water bath, and filling it with 

 water at 65° it is dropped into the opening so as to allow the 

 beaker to be suspended by its rim in the water contained in 

 the bath. The tubes, which are open at. both ends, are placed 

 in the beaker, with a delicate thermometer, and a small gas 

 flame placed below the bath, so as to raise the temperature of 

 the water very slowly. As the fat melts in the tubes it 

 rises up in consequence of the water entering at the lower 

 end, and the temperature at which it rises is read off upon 

 the thermometer. 



The author's experiments were declared to be very satis- 

 factory, as a repetition with the same fat gave the same 

 temperature in all cases within a degree, and generally within 

 a smaller range. 



There are certain precautions mentioned by the author the 

 most important of which are, that the tubes should have' 

 notched or oblique ends, so as to allow of the free ingress of 

 the water, and that they should be placed upright in the 

 beaker ; the level of the fat should be about a quarter of an 

 inch below the surface of the water. 



A plan devised by Mr. Charles Heisch, and pubHshed 

 almost simultaneously with Dr. Tripe's, differs mainly in the 

 fact that the melting tubes are drawn out to a capUlary 

 point, the capillary portion being about 3 inches long, the rest 

 of the tube having a bore of 0'2 inch. 



Mr. Heisch gives the following table, comprising a series 

 in which two portions of each sample were taken in separate 

 tubes : — 



