64 MAINE AGRICULTURAL EXPERIMENT STATION. 



tory forms that can be obtained at a moderate price may be 

 mentioned here, one known as the Swedish acid bottle and one 

 offered for sale by Emil Greiner, Xew York City. These can 

 be obtained from dealers in creamery supplies. 



Centrifugal Machine. All machines made by reliable dairy 

 supply firms are suitable for this purpose. A machine must 

 be capable of making 800 to 1200 revolutions per minute, ac- 

 cording to the diameter of the wheel. A small wheel should 

 make more revolutions than a large one. A wheel should not 

 be less than 16 inches in diameter and need not be more than 

 20. Steam turbine machines are to be preferred for factories 

 or wherever high pressure steam is available, as they maintain 

 an even speed, prevent cooling of the bottles and supply hot 

 distilled water for filling. They should be furnished with a 

 speed indicator. 



Sulfuric Acid. This acid should have a specific gravity of 

 1.820 to 1.825. It is very important that the acid used be of 

 the right strength. If it is too weak, the curd will not all be 

 dissolved, and will make the test unsatisfactory. If the acid is 

 too strong, the fat is liable to be blackened, or black particles of 

 charred matter will accumulate just below the fat column and 

 interfere with the reading. If the acid is only slightly too 

 strong or weak, a little less or more than the prescribed amount 

 may be used and give good results. It is better to have the acid 

 right and use the amount directed. 



If acid is bought in the carboy, the wooden case surrounding 

 it should never be removed, as by so doing the risk of breakage 

 is greatly increased. All carboys or bottles in which acid is 

 kept must be tightly stoppered, or the acid will absorb moisture 

 from the air and become too weak for use. 



One should always use the greatest care in handling sulfuric 

 acid as it is very corrosive, causing serious burns when allowed 

 to remain upon the skin and destroying clothes when it comes in 

 contact with them. "When spilled upon the hands or clothing, 

 it should be washed off immediately, using plenty of water. If 

 the color has been changed on the clothing it can usually be 

 restored by saturating the spot with ammonia water. 



Apparatus for Filling the Bottles with Hot Water. A very 

 convenient arrangement for this purpose consists of a galvan- 



