Manchester Memoirs, Vol. XL VIII. 



Plate VIII. 



Fig. I shews the Arsenic mirrors obtained when using 50 c.c. of solutions 

 containing the amounts of Asj^Og in the fractions of a grain per gallon given 

 below, by the Committee's Electrolytic Method as compared with the results 

 obtained by other methods. 



Electrolytic Method 

 with granulated Zinc 

 ''•'^'■■■■lll in contact with plat- 

 inum wire as Kathode 

 (3 amperes), with 

 cooling. 



.. *■ p . •••••■■ Marsh-Berzelius 



i ,^ Method, 



with cooling. 



Committee's Electro- 

 "■*•"•« I • lytic Method — wzM 



cooling (3 amperes). 



SIB 



1 I 



Ditto without cooling 

 (5 amperes). 



t i '«J( i« I I 



My own Electrolytic 

 Method with Zinc rod 

 as Kathode (3 amperes 

 with cooling). 



• » I I ■■ f I I I 



Ditto with cooling 

 (5 amperes). 



blank -^^-t^ J^ -^ ^\^ ^sfc- .j^-^ ^ ^\^ ^^ ^ -^V grain per gallon (when 



Fig. 1. 



using 50 c.c. 



Fig. 2 shews the influence of amyl alcohol on the formation of Arsenic mirrors 

 when using the Committee's Electrolytic process, with 50 c.c. of solutions 

 containing the quantities of As^Og per gallon given below, "without" means, 

 without amyl alcohol. 



with- 

 out with 





with- 

 out with 



|| II 



with- with- 



out with out with 2 c-c. amyl alcohl. 



, _ ^ 5amperes without 



cooling. 



blank 



Fig. 2. 



grain AS4O8 per gallon 

 when using 50 c.c. of the 

 solution. 



