328 AGRICULTURE FOR COMMON SCHOOLS 



from the rest of the contents and is ready to be read. The 

 figures opposite the long marks indicate the per cent., while 

 the short marks indicate tenths of one per cent. The reading 

 is done by subtracting the figure at the bottom of the fat 

 column from that at the extreme top of the column. A pair 

 of dividers is useful to aid the eye in reading correctly. The 

 reading should be done quickly while the fat is hot. 



For the testing of cream a bottle with a large neck and 

 graduated up to 35 per cent, or more is used. In the testing 

 of cream 18 grammes is weighed into the bottles. For skim- 

 milk and buttermilk a bottle with two necks is used. One is 

 large, for putting the acid and milk into, and the other is quite 

 small, and in this the fat gathers and is read off in hun- 

 dredths of one per cent. 



The taking of the sample for testing is a very important 

 matter. In the case of whole milk it is best to take a sample 

 as soon as the milk is drawn from the cow, and in that case 

 the milk should be poured from one bucket to another two 

 or three times in order to get it thoroughly mixed. If the 

 milk has become cold and the cream has risen it will take a 

 great deal of pouring and mixing to get the fat globules com- 

 pletely distributed again. The sample may be put into a small 

 bottle. The sample for testing is taken from the larger 

 sample by means of a pipette and put into the test bottle. 

 The testing is done at convenience. The same care in mixing 

 should be taken with cream or skim-milk. 



If it is desired to get an average of the fat produced by a 

 cow in a week, without testing each milking, a small sample 

 is taken at each milking and put into a pint fruit-far. A bit of 

 bichromate of potash or corrosive sublimate should be put 

 into the bottle to keep the milk from souring. If it sours a fair 



