liY J. BROWNLIE HENDERSON, F.I.O., AND L. A. MESTON 175 



grams of water. If X grams of water are now added 

 to 100 grams of milk, the cyrstalloids are dissolved in 

 (W + X) grams of water. 



Now let D be the observed freezing point of the 



diluted milk expressed in — degrees (Centigrade then 



Oo.> X W 



X-= AV 



D 



As the value W can easih^ be . calculated when the 

 percentage of Fat and the specific gravity are known, the 

 value of X can also be obtained. 



This formula, however, is not accurate from a theoretical 

 point of view, because on diluting with water the electrolytic 

 and hydrolytic dissociation of the salts is increased and 

 oonsequently the freezing point decreased. This error 

 is, however, sufficiently compensated for practical purposes 

 if the calculation is based on the volume instead of the 

 weight. The error thus introduced compensates the one 

 arising from the increased dissociation. 



Examples of Bonnerna's Formula. 

 IWILK. 



8j)scific Gravitv .. .. .. 1'0]42 



Total 8oUds (weighed) .. .. 5-9 



Fre.-^z.ing Point .. .. .. —0.255 



0-55 X 94- 1 



X=: 94-1 



0-255 



•--(203-^>4-l\ X 100 



203 



— 5S-(>t per cent. Abater by weight. 



53-64 X 1-0142 = 54*4 per cent. Water b}' volume against 63-7 

 per cent. Water by A'olume calcnUited by Winter's formula. 



MILK. 



Specidc Gravitv .. .. *. 1-0298 



Total .Solids ' 11-97 



Pieezing Point 0-526 



0-55 X 88-03 



X^ -88-03 



0-52i> 



={92 -04- 88 -03) X 100 



92-04 



=4-35 Water Vty weight. 



=4-48 Water bj' volume again'*! 

 4-32 Water by volume according to W^inter's Formula. 



