154 H. S. H. WARDLAW. 
1. Effect of removal of the deposit on the superfluid. 
2. Rate of deposition. 
3. Ash of the deposit; its variation with the time of 
spinning. 
4, Amount of calcium and phosphorus in the ash of the 
deposit. 
5. Amount of nitrogenous and non-nitrogenous organic 
matter in the deposit. 
6. Solubility of the deposit in water. 
1. Effect of removal of the deposit on the superfluid. 
Moore and Roaf (1908) have obtained results which 
indicate that electrolytes in solution may become associ- 
ated with a colloid present in such a way that, although 
their effect on the freezing point of the solution is not 
altered, their conductivity is very considerably reduced, 
and they are withdrawn from the solution when the colloid 
is removed. It was thought, therefore, that some such 
effect might be observable in the present case, and that 
the removal of suspended colloidal substance from the milk 
might also mean the removal of some dissolved matter. A 
series of determinations of the freezing point was there- 
fore made on milks before and after the removal of different 
amounts of suspended matter. These determinations of 
the freezing point were made in a glass vessel without an 
air mantle. The tube containing the liquid to be frozen 
dipped directly into a cooling bath of ice and salt at a 
temperature of —2° to —3° C. (not lower), both the bath 
and the liquid to be frozen being kept thoroughly stirred. 
In this way a determination of the freezing point could be 
made in less than ten minutes and the agreement between 
separate determinations on the same liquid was satis- 
factory, as the following figures show :— 
