52 R. H. Lee-—Atomic Weights of Cobalt and Nickel. 
the quantity of water in each of these salts, and afterward the 7 
percentage of metallic nickel. This last determination was ef- 
fected by first carefully heating the salt in a platinum crucible, 
employing the ring-burner of Dr. Gibbs so as to apply the heat 
at the rim of the crucible first, and afterward in successive zones _ 
until the bottom of the crucible was reached. The remaining ; 
carbon was then burned off in a current of pure oxygen, and | 
the oxide of nickel finally reduced by igniting it in carefully | 
purified hydrogen. The f 
strychnine were prepared by double decomposition, the salts 
being but slightly soluble in cold water. They were then re- 
peatedly recrystallized, and when tested by the spectroscope | 
were found to be absolutely free from potassium. All of these 7 
salts crystallized in very pale yellow needles. : : 
My analyses of the brucine salt led to the following results: | 
0-4496 gr. dried at 120° C. lost 0°0258 gr. OH,=5°738 p.c. | 
water. | 
The formula Ni,Cy,.(C.,H,,N,0,),H,+100H,, requires — 
5°929 p. c. 
No. Salt taken. Nickel. Nickel, p. e. At. weight. 
ss 0°3966 0°0227 5°724 7°92 
8 0°5638 0°0323 5°729 57°98 
3. 0°4000 070230 5:750 58°20 
4, 0°3131 0°01795 5733 58°02 
5. 0°4412 0°0252 ye 24 57°79 
6. 0°4346 0°0249 5°729 57°98 vi 
Mean, 5°7295 57-98 
The probable error of the mean percentage of nickel is 
+0°008, and the atomic weight of nickel 57-98, with a probable 
error of +0°089. 
Six analyses of the strychnine salt were then made: 
0°3399 gr. dried at 112° C. lost 00178 gr. water = 5-24 p. c 
The formula Ni,Cy,,(C,,H,.N,0O2),H,+80H,, requires 
5°45 p. 
No. Salt taken. Nickel. Nickel, p. c. At. weight. 
1 0°5358 0°0354 6°607 1 
2 0°5489 0°0363 6°613 58°21 
3 0°3551 0°0234 6°589 57°98 
4 0°4495 0°0297 6°607 58°15 
5. 0°2530 070166 6°561 57°72 
6. 0°1956 0°0129 6595 58°04 
Mean, 6°595 58-04 
The probable error of the mean percentage of nickel is 
+0018, and the atomic weight 58-038, with a probable error 
of +0°119. 
The mean of all my determinations of the atomic weight of 
uble cyanides of nickel, brucineand | - 
