204 Associations and Socict'ies 



made from time to time, such papers can be looked upon as being 

 well up to the Standard of the German makes, and in certain respects, 

 superior. The papers are classified according to their physical char- 

 acteristics, in which the main question dealt with is that of bulk. 

 Experiments were illustrated showing the relation of this factor to 

 the rate of filtration and absorbency tests. 



The chemical side of the question, with regard to choice of ma- 

 terial, was next dealt with, and showed the common impurities f ound 

 and the methods of removing same. Organic impurities were also 

 described and an actual determination of such an impurity as oil, 

 was outlined. 



The application of filter paper for use in milk analyses and other 

 work was also described. 



Pink colour on the surface of margarine. A. W. Knapp, 

 B.Sc, F. I.e. Beakers of margarine left about in the lab. often 

 become pink on the surface. This colour is due to mineral acid 

 vapours in the air of the lab. acting upon the azo-colour in the mar- 

 garine. As butters do not give the colour, it can be used as a sort- 

 ing test as follows. The filtered fat solidified in small beakers is 

 placed in a crystallising dish, on the bottom of which is a filter paper 

 soaked in strong hydrochloric acid. The dish is covered, and the 

 fats examined after 2 hr. A pink colour indicates that the sample is 

 probably margarine. The hydrochloric acid was found to diffuse ^ 

 in. into the fat in lo days. 



A rapid method for the estimation of fat in powders. S. B. 

 Phillips. The method was invented for the estimation of fat in 

 cocoa, and is applicable to any substance which can be finely divided. 

 The process consists of extracting the fat, from a known quantity 

 of the substance, with trichlorethylene, and of determining the fat 

 in an aliquot part of the sol. Such a quantity of the substance as is 

 likely to contain 1.5 to 3.5 gm. of fat, is weighed by difference into 

 a 6 oz., wide-mouthed, stoppered bottle (about 3.5 in. high to the 

 Shoulder), 100 cc. of solvent at room temp. is added from a pipette, 

 and the mixture thoroughly shaken. The filter used is made by 

 folding 2 filter papers (9 cm. diam.) together into the shape of a 

 Soxhlet thimble and tying them into a small perforated cork (hole 

 about 8 mm. ) which is then fixed on the end of a 20 cc. pipette. Filtra- 



