10 July, 1918.] The Bahcock Tester on the Farm. 407 



therefore provided by law that cream shall be weighed directly into the 

 flask. 



For this purpose sensitive scales are used (Fig. 4&). These are 

 obtainable for about 25s. The sample bottles should be placed in water, of 

 from 90 to 100 degrees, until the contents are fluid enough to run freely. 

 The flask is then balanced on the scales; approximately by the counter- 

 poise on the beam, then by small shot or pellets of paper on the tray. 

 The weight is moved along the beam to the 9 gramme mark, and the 

 cream (being thoroughly mixed) is run in with a pipette until the weight 

 is balanced. If a drop too much is run in it may be removed by a fine 

 tube which can be inserted to the bottom of the flask. Nine grammes 

 of cream, instead of 18, are taken because the flasks in use in this 

 country (Fig. 6) are graduated to 30 per cent., and all the fat of 40 per 

 cent, cream would not go into the graduated neck. Nine c.c. of water 

 is then run in. After adding 17.5 c.c. sulphuric acid, shake until the 

 casein is all dissolved. There is a frosted spot on the flask on which a 

 number should be marked with an ink pencil to correspond with the 

 number of the sample. The procedure now is the same as with milk. 



In reading the cream test, the fat is measured from a to c, not to 

 d or b (Fig. 9). The cream flasks are graduated for 18 grammes and as 

 9 grammes have been taken, tbe reading has to be doubled. 



To calculate the result. — The weight of cream is multiplied by the 

 test and divided by 100. This gives the amount of butter fat that the 

 factory should pay for. 



Exarnple. — A can of cream contains 95 lbs. net. The test reads 22. 

 Then 22 v 2 = 44, gives the correct percentage of fat in the cream. 

 95 X 44 -4- 100 = 41.8 lbs. butter fat in that can of cream. 



Skim Milk. 



It is quite as important to test the separator milk as to test the cows. 

 Frequently, very heavy loss is experienced owing to the separator getting 

 out of order or as a consequence of its not being properly worked. A 

 check should therefore be kept by regularly testing the skim milk. 



Special double necked flasks (Fig. 7) are used for testing skim milk. 

 They have a wide tube, reaching nearly to the bottom of the flask, through 

 which the milk and the acid are run in. As the graduated neck is of 

 small bore, it is possible to estimate the loss of fat clearly. 



Take 17.6 c.c. of skim milk into the flask, as in new milk, and 17.5 

 c.c. or a little more acid may be used — up to 20 c.c. It is better to add 

 half the acid first and mix it with the milk, then add the remainder and 

 shake the contents of the flask until all the casein is dissolved. The 

 mixing must be done carefully, so that none of the liquid may be forced 

 into the graduated neck and thus lost. The flask must be placed in the 

 machine with the graduated neck towards the outside, so that, while the 

 machine is running, the graduated neck will be uppermost; otherwise, 

 some of the fat may lodge behind the tube and not rise into the neck. 

 The procedure then is the same as with new milk. The loss of fat, as 

 indicated by this test, should be kept below .1 per cent, or one-tenth of 

 one per cent. 



It is best to use rain water for testing where possible. If spring 

 water containing lime, &c., is used, it may cause froth to appear on top 

 of the fat column. This should be avoided. 



