26o 



Journal o} Agricultural Research 



Vol. in, No. 3 



Table IV. — Observed and calculated densities of milk and cream at different temperatures 

 and with different percentages of fat — Continued 



Fat 

 content. 



D«,° 



Per cent. 



25 



25- 



30- 



30. 



30- 



o- 9975 



-9995 



.9912 



30- 



35- 



40. 



.9891 



.9910 



. 9926 



.9841 



-9799 



These results were then plotted on coordinate paper of such a size that 

 densities could be plotted and read to one in the fourth place, and « and /? 

 to one in the fifth and sixth places, respectivelj'. From these curv^es the 

 values of n and /9 for various densities of milk and cream are tabulated 

 in Table II. The curves are shown on a reduced scale in figure i. 



In figure 2 is shown the relation between the density of the samples 

 and the percentage of butter fat contained in them. 



Having determined the density of each sample and the rate of change 

 of density with change of temperature, it was possible to calculate the 

 volume of any sample at any temperature in terms of the volume at any 

 other temperature within the limits covered. 



It was suggested by the Dairy Division of the Bureau of Animal 

 Industry that 20° C. (68° F.) be chosen as the standard temperature and 



