1354 
Evidently the velocity of rediiction of mercnric chloride by pot- 
assinm oxalate is very rapid in comparison witli other acids and it 
will also be seen that the amonnt of inei'cnrons chloride forrned is 
proporlional lo tlie time of ex[)Osnre. (See table p. 1353). 
Moreover it bas been found out tliat canesngar solntion, hydroxyl- 
aminehydi'ochlui'ide, hydrazine hydi-ochloride and ferrous sulphate 
can slowly rediice mercnric chhride in presence of sunlight ; in 
ditfnsed dayiight there is no appreciable rediiction. 
Volume of solution 
50 hours 
! Amount of HgCl 
I forrned in grams 
11) Cane sugar solution SOc.c.and 
10 c.c. HgClo 
50 cc. Molar cane sugar and 10 C.C. 
fo 
12) 50 c.c. hydroxylamine hydrochlo- 
ride 2N (factor 1.128) and 10 c.c. 
fo 
50 c.c. hydroxylamine hydrochlo- 
ride ^ (factor 1.128) and 10 c.c.^ 
HgCl, 
13) 50 c.c. 2N (factor 1.156) hydrazine 
N 
hydrochloride and 10 c.c. y^HgCL. 
N 
50 c.c. — (factor 1.156) hydrazine 
N 
hydrochloride and 10 c.c. y^HgClo. 
N 
14) 50 c.c. Ferrous sulphate and 
10 C.C. ^ HgCb. 
Do 
50 hours 
55 hours 
80 hours 
95 hours 
90 hours 
85 hours 
25 hours 
45 hours 
0.00752 
0.02684 
0.02175 
0.00435 
0.02375 
0.00463 
0.02512 
0.04987 
When a solntion of mercnric chloride is boiled even for hours 
togelher wilh tartaric acid, citric acid, or any of these reducing 
agents, there is no appreciable rediiction but in presence of sunlight, 
only the rediiction takes place even at the ordinary temperatiire. 
Since the velocity of these rediiction processes is very slow, these 
changes cannot be nsed in measuring the Chemical intensity of sun- 
light and hence these mixtures cannot serve as photometers. 
