lO 



Thomson, Detection of Arsenic in Beer. 



Amperage. 



Quantity of Hydrogen 

 liberated per minute. 



Size of flame as 



measured by Calipers 



placed close to 



the flame. 







Milliir 

 Height. 



etres. 

 Width. 



3 



21 C.C. 



4 



3 



4 



28 „ 



4-5 



4 



5 



35 » 



5 



5 



6 



42 „ 



5-5 



5 



7 



49 » 



6 



5-5 



8 



S6 M 



7 



5-5 



Influence of Amy I Alcohol and of Sugar on the detection 

 and estimation of Arsenic. 



The Committee say that beer may be tested directly 

 in their appaartus, and to prevent frothing they recom- 

 mend the addition of amyl alcohol, which they say does 

 not interfere with the result. To test this point, I made 

 a number of experiments by using 50 c.c. of solutions 

 containing different quantities of AS4O6 per gallon. 



The first series of experiments was made in the 

 Committee's electrolytic apparatus with a current of 

 5 amperes, and without cooling the tube at the point at 

 which the mirror was produced. The process followed 

 being exactly the one recommended by them. 



Four different quantities of ASiOe were tried, viz., oV tts^ 

 1^75^, and o^th of a grain per gallon, and two experiments 

 were made with each of these quantities without the addi- 

 tion of amyl alcohol, and two with 2 c.c. (as recommended 

 by the Committee) of amyl alcohol in the apparatus, the 

 tubes containing the resultant mirrors were mounted and 

 photographed, and the results obtained are shown in 

 Plate VIII., Fig. 2. The first tube is a " blank" test done with 

 the reagents alone, and it shows no trace of mirror. The two 



