TRANSACTIONS OF SECTION B. 507 



Firstly. Each analyst being allowed to fix this percentage himself, we have 

 different standards employed, and consequently may have a milkman fined in one 

 town for selling an article which a neighbouring analyst may declare pure. 



Secondly. The percentage fixed upon cannot be the lowest contained by pure 

 milk, because we do not know it. The amount found by Dr. Voelcker (93 of 

 solids) is the lowest at present known, but a lower number may be found. 



Thirdly. This lower limit is so low that with an ordinary sample a considerable 

 amount of watering may take place without the possibility of detection. 



For many obvious reasons it is necessary to remedy this state of things. One 

 method only appears to offer a chance of success, briefly, this is to buy and sell milk 

 by quality instead of by quantity. The difficulty of introducing this practice is 

 more imaginary than real. One easy method is as follows : — Divide the milk into 

 two qualities, first quality and second quality. The former will include all milk 

 containing 12 - per cent, of solids or 9-0 per cent, of " solids not fat " or more, and may 

 be sold, say, at 4d. per quart. The latter will include all milk containing less than 

 these numbers, and may be sold at '-'^d. per quart. If a sample of first quality milk 

 be sold which, on analysis, does not contain the stated quantity, the vendor will be 

 fined. The great difficulty here is in making the division into two qualities. In 

 order to do this effectually, some simple instrument capable of making a rough 

 analysis is required. At present such an instrument does not exist, but we may 

 rely on one being forthcoming if the need be felt. 



In conclusion, the following advantages are claimed for this method : — 



1. The analyst not being called upon to decide upon the purity of the article, 

 but simply whether it contains a certain percentage of solids or of " solids not fat," 

 cannot make such deplorable mistakes as at present. 



2. The vendor will not be fined unjustly. 



3. It will tend to stop adulteration because a better price can be obtained for a 

 better article. 



4. An article of greater constancy will be supplied to the public. 



On some Fluor Compounds of Vanadium. By Professor H. E. Roscoe, 



Ph.D., F.B.S. 



