THE BABCOCK TEST 51 



2. Not enough acid. 



3. Too low temperature. 



Cleaning Test Bottles. As soon as the test is read, 

 the bottles are emptied by shaking them up and down so 

 as to remove the white sediment. Next wash them in 

 hot water containing some alkali, and finally rinse them 

 with hot water. Occasionally the bottles should be rinsed 

 with a special cleaning solution, which is made by dis- 

 solving about one ounce of potassium bichromate in one 

 pint of sulphuric acid. A small brush should also oc- 

 casionally be run up and down the neck of the bottle. 



Reading Cream Tests. Reading the extremes of the 

 fat column, as is done in the case of milk tests, ^ives too 

 high a reading. This error is due to the meniscus at the 

 top of the fat column, the size of which varies with the 

 width of the neck of the bottle. Farrington and Woll 

 recommend reading from the lowest extremity of the fat 

 column to the bottom of the meniscus. This is the rnethod 

 now commonly employed. Eckles and Wayman recom- 

 mend removing the meniscus by adding a small quantity 

 of amyl alcohol (colored red) to the top of the fat col- 

 umn. This method gives very satisfactory results. 



