142 CANADIAN DAIRYING. 



rule. The chart is more accurate, as it is not impor- 

 tant to have an exact depth of cream in the test tube, 

 which is absolutely necessary when measuring with 

 a rule. 



The oil-test may not be considered a very reliable 

 test for cream, and a buttermaker has to do a good deal 

 of guessing to make his oil tests and churn results 

 agree. In order to get approximately accurate tests, 

 it is important that the drivers be accurate in measur- 

 ing the cream, and careful in mixing it before taking a 

 sample. It is also necessary to take samples from 

 all the lots of cream delivered by or got from a patron 

 each time. The buttermaker should be careful to get 

 a complete and distinct separation of butter oil, water, 

 and curdy matter in each test tube. He should also 

 be careful to read accurately. 



The following are the directions given in Bulletin 

 114, from the Dairy School, in connection with the 

 Ontario Agricultural College : 



" To make an Oil-Test. Upon their arrival at the creamery, 

 place the samples in a warm place, as over the boiler, and leave 

 over night to ripen thoroughly. They will not churn properly 

 unless well ripened. 



" The next morning place the samples in water at a tempera- 

 ture of about 90 degrees ; and as soon as the cream will 

 flow freely from one end of the tube to the other, place in the 

 oil-test churn and begin churning. Should the cream at any 

 time cool and thicken, place the samples in warm water to 

 liquefy the cream again. Continue churning until there is evi- 

 dence of a clear separation of the fat ; then place the samples 

 in hot water, at a temperature of from 160 to 170 degrees, for 

 from fifteen to twenty, minutes. 



" If the separation be complete, the fat will be clear arid 



