proceedings of section b. 107 



Conclusion. 



Taking the price of calcium acetate (crude) at 8d. a lb., tliat of 

 pyridine (refined) at 4s. 6d. a lb., that of charcoal at 20s. per ton, it is 

 found that the value of the products per ton joi green plant is approxi- 

 mately 8s. It is considered extremely doubtful that this would cover 

 the cost of clearing the ground. The value of the gas produced has not 

 been taken into consideration in calculating the value of the products, 

 as it would be most profitably used in assisting to heat the retort. 

 It has a calorific value of about 13 B.T.U. per cubic foot. 



In conclusion I take this opportunity of acknowledging my deep 

 obhgation to Messrs. J. H. Maiden and J. Cronin, and to the Govern- 

 ment of Queensland for supplying me with the material used in this 

 research, to Mr. D. Avery for the loan of his gas analysis apparatus, 

 and to Professor Masson for his interest and advice. 



10.— A REACTION OF RASPBERRY JUICE WITH THE WOOL 



TEST FOR ARTIFICIAL COLOURING MATTERS. 



By Professor J. A. Schofield, University of Sydney. 



When testing a number of samples of raspberry juice for the presence 

 of artificial colouring matters, by means of the well-known wool test, 

 one of the samples to which no artificial colouring matter had been added 

 gave an unexpected positive reaction, the final wool being dyed a fairly 

 deep brown tint. 



The method of applying the wool test used in the experiments is 

 fully described in Preservatives in Food and Food Examination, by 

 Thresh and Porter (1906), p. 369, and is briefly as follows : — 



Two portions of the sample, 50 c.c. to 100 c.c. each, are taken, 

 one is acidified with HCl and the other made alkaline with NH^OH, 

 about 1 foot of wool, purified by boiling in very weak NaOH, is immersed 

 in each and the solution heated at the boiling point for about an hour ; 

 the dyed wools are then removed, pressed between filter paper, and 

 washed twice with boiling water. The wool from the acid solution 

 is then placed in weak NH^OH, and that from the alkaline solution in 

 weak acetic acid and the two are boiled. The dye is dissolved from 

 the wool, which is then removed from the solution. The first solution 

 is then acidified with acetic acid, and the second made alkaline with 

 NH4OH, fresh pieces of avooI a few inches long placed in each, and 

 the solutions heated. The dye is taken up again by the wool, a dye of 

 the acid type colouring the wool in the first solution, a basic dye that 

 in. the second. 



Thresh and Porter (p. 370) state that all the vegetable colouring 

 matters they examined by this test gave merely a dirty appearance to 

 the final wool, and no record could be found of the production of a 

 stain on the final wool in any of the literature available. 



