40 Testing Milk and Its Products. 



Small strips of tin or copper with a number stamped 

 thereon are sometimes attached as a collar around the 

 necks of the bottles. They are, however, easily lost, 

 especially when the top of the bottle is slightly broken, 

 or at any rate, are soon corroded so that the numbers 

 can only be seen with difficulty. 



The best and most permanent label for test bottles is 

 made by scratching a number with a marking diamond 

 into the glass directly above the scale on the neck of the 

 bottles. In ordering an outfit, or test bottles alone, the 

 operator may specify that the bottles are to be marked 1 

 to 24, or as many as are bought, and the dealer will then 

 put the numbers on with a marking diamond. 



A careful record should be kept of the number of the 

 bottle into which each particular sample of milk is meas- 

 ured. Mistakes are often made when the operator trusts 

 to his memory for locating the different bottles tested at 

 the same time. 



46. Cleaning test bottles. The fat in the neck of the 

 test bottles must be liquid when these are cleaned. In 

 emptying the acid the bottle should be shaken in order 

 to remove the white residue of sulfate of lime, etc., from 

 the bottom; if the acid is allowed to drain out of the 

 bottle without shaking it, this residue will be found to 

 stick very tenaciously to the bottom of the bottle in the 

 subsequent cleaning with water. 



A convenient method of emptying test bottles is shown 

 in the illustration (Fig. 13). After reading the fat col- 

 umn, the bottles are placed neck down, in the half- inch 

 holes of the board cover of a five-gallon stoneware jar. 



