DAIRY FARMING DAIRYING. 



681 



Examinations of the chemical properties of Danish butter fat, 

 E. Holm aud P. V. F. Petersen (46. Rpt. Kgl. Yet. LandhoJidjskolen 

 Lah. Landokon. Forsog \^Copenliagen\ 1900., pp. 106). — This work was 

 extended over 4 years, 1896 to 1900, 7,834 samples of butter from 

 about 800 creameries being examined, as well as butter from indi- 

 vidual cows on different farms. 



Exam! nation of hatter f<d in Danish creamery hutter. — The refract- 

 ive index of all samples ranged between 48.6 and 54.9, over 80 per 

 cent of the samples being between 51 and 52. There was practi- 

 cally no difl'erencc in the index of butter from dili'erent parts of 

 Denmark, and but slight difference between that from large estates 

 and creameries. Regular seasonal changes were observed in the 

 refractive index, Reichert number, and iodin number. The average 

 refractive index for 4 j^ears, Reichert number for 3 years, and iodin 

 number for 2 years are shown l)elow: 



Average residtf! for DauisJi butter fat per month. 



April 



May 



June 



July 



August . - 



September 



October 



November 



December 



January 



February 



Marcb 



Average 



Refractive 

 index. 



51.0 

 .il.l 

 51.1 

 51.6 

 52.1 

 .52.0 

 52.8 

 51.0 

 .50.2 

 50.5 

 .50.6 

 .50.8 



51.3 



Reiche-t 

 number. 



30.1 

 30.0 

 30.4 

 30.2 

 28.8 

 27.5 

 27.5 

 29.6 

 30.7 

 30.9 

 31.0 

 30.9 



29.8 



Iodin 

 number. 



033.4 



a 35. 



a 37.1 



a 38. 4 



a 39.0 



41.6 



44.0 



36.6 



33.0 



a 33. 3 



a 34. 5 



a34.1 



30.7 



a One year only. 



The highest values for refractive index and iodin number are coin- 

 cident with the lowest Reichert numbers, a gradual increase or decrease 

 of the latter being accompanied by a change in the opposite direction of 

 the former. A difference of 1° in the refractive index was found to 

 correspond to a difference of about 3 in the iodin number. 



Forty -i"our samples of artificial butter of Danish, Swedish, Norwe- 

 gian, Dutch, and German origin gave refractive indexes ranging from 

 57 to 61.5", the minimum, therefore, being 2.1° above the maximum 

 for pure Danish butter. Mixtures of artificial and natural butter fat 

 containing 10 to 90 per cent of the latter gave a refractive index iden- 

 tical with the calculated index in all cases. 



The authors show that the quality of butter and its commercial 

 value stand in no relation to its composition, and that a perfect guar- 

 antee of purity can not be established by means of chemical standards. 



Examination of hutter fat from, individual cows. — Six cows were 

 selected from each of 3 Danish dairy farms, 2 of each lot being fresh 

 milkers, 2 in about the middle of their lactation periods, and 2 old 



