70 Testing Milk and Its Products. 



pelled. By simply boiling, many hard waters will be 

 rendered soft and adapted to use in the Babcock test, 

 as most of the carbonates which cause this foaming are 

 thereby precipitated. 



If the test has been completed, and a layer of foam 

 appears over the fat, it may be destroyed by adding a 

 drop or two of alcohol. If this is done, the fat column 

 should be read at once after the alcohol is added, as 

 the latter will soon unite with the fat and increase 

 its volume. (See also 96 on the use of glymol in cream 

 testing.) 



8i. Reservoir for water. When only a few teste are 

 made at one time, hot water can be added with the 17.6 

 cc. pipette. If many tests are made, the water may be 

 conveniently and quickly filled into the test bottles by 

 drawing it from a small copper reservoir or tin pail 

 suspended over the testing machine.^ The flow of water 

 through a rubber tube connected with the reservoir, is 

 regulated by means of a pinch cock. The water must 

 be hot when added to the test bottles so as to keep the 

 fat in a melted condition until the readings are taken. 

 Most turbine testers are now made with a very conven- 

 ient water reservoir attached to the tester (figs. 22-24). 



The use of zinc or steel oilers, or perfection oil cans 

 has been suggested as a convenient method of adding 

 hot water to the test bottles, but most operators prefer 

 to add water to the bottles by means of a piece of rub- 

 ber tubing connected with a reservoir, as shown in the 

 illustrations just referred to. 



> Ordinary tinware will soon rust with water standing In It, and cop- 

 per reservoirs are tlierefore more economical. 



