labelled, and for this purpose nothing is better than painting on 

 them figures about 1 inch high in Aspinall's black enamel. 



To secure speed in sampling, hold the dipper in the right hand 

 and the sample bottle in the left, lift off the cover with the 

 right hand, fill the dipper, empty it into the bottle, and replace 

 the cover. 



Pellets of a preserving agent must be used to prevent souring. 

 These pellets can be purchased in two sizes, a 25 gram size, to 

 preserve 8 oz. for a fortnight, or a .'5 gram, to preserve the 

 same quantity for a month. A pellet should be placed in the 

 bottle before the first sample is added. It will be found an 

 advantage to add at the same time a few grains of small shot, 

 which will assist in the future mixing. When the sampling is 

 over for the day give each bottle a gentle rotary motion. This 

 serves the double purpose of mixing the contents and of pre- 

 venting the formation of a layer of dry cream, which would be 

 found difficult to deal with in the testing. The use of any excess 

 of the preserving agent should be avoided, as this practice gives 

 rise to difficulties in testing. The preserving agent is extremely 

 poisonous, and the contents of the test and sample bottles should, 

 therefore, be emptied in some safe place. 



If a sour sample has to be tested add a few grains of shot and 

 mix well. By means of a graduated measure take 100 c.c. and 

 add thereto 2 c.c. of strong ammonia, mix well, and allow to 

 stand until on shaking air bubbles rise as freely as they do in 

 fresh milk. The sample may then be tested in the usual 

 manner if the observed percentage of fat be increased by l-50th 

 of itself to correct for the dilution by ammonia. 



To send samples from auxiliaries to a central creamery use 

 4 oz. narrow-necked bottles, which, after the addition of a few 

 grains of shot, should be completely filled to prevent churning 

 in transit. 



PREPARATIONS FOR 



"When only a few tests are required the pipettes specified in 

 No. 4 of the equipment, on page 3, will be found sufficient, 

 When, however, a large number of tests have to be made it will 

 be found more convenient to measure the acid by the burettes 

 specified in No. 5 of the equipment on page 3. 



It is desirable that the testing room should contain more than 

 one test bottle of guaranteed accuracy, to serve as a standard of 

 comparison. Pipettes and bottles are tested under the supervision 

 of the Director, National Physical Laboratory, Old Deer Park, 

 Richmond, Surrey, at a fee of 3d. for each pipette, and 6d. for 

 each test bottle. The carriage on sttch articles must be prepaid. 



Any test bottle which gives mean results differing by more 

 than 05 per cent, from the results obtained in the standardised 

 bottle should be discarded. 



