264 Hartlev — Tlie Action of Heat on the Absorption Spectra and 



dark green hexagonal prisms on standing over sulphuric acid. These crystals, 

 while extremely deliquescent in air, were efflorescent when standing over sulphuric 

 acid, and rapidly became transformed into a black amorplious powder. They could 

 not be dried by crushing between blotting paj^er, as it appeared to form the black 

 anhydrous compound on coming in contact with the salt. This is probably a 

 combination of the salt with cellulose in a manner similar to that of other chlorides. 



Light was observed to have a distinct action on the substance so that the third 

 determination of water in the salt was carried out as far as possible in darkness, 

 and the weighings performed in a pair of ground watch-glasses. The nickel was 

 determined as oxide, and the iodine as silver iodide. 



The composition of the salt was found to be NiL . THoU, and not that usually 

 accejited Nil2"6H20. 



Determination of the Water. 



I. II. III. 



Weight of salt taken, 2-4053 4'4870 4-3206 



Loss of weight, 0-7099 1-3227 1-1850 



HjO per cent., 29-51 29-47 27-42 



Of these I. was kept over sulphuric acid, and weighed at intervals during 

 eighteen days. 



II. was heated at 100" C. in the steam-oven for ten successive periods of about 

 three liours each, the salt cooled in a desiccator freely exposed to the light. 



III. was heated at 100 C. for seven successive intervals of about three hours 

 each ; at each weighing the salts were enclosed in air-tight watch-glasses, and 

 allowed to cool in the dark. 



Analyses. 



Determination of the Water. 



I. II. m. 



Weight of salt taken, 2-4053 4-4870 4-3206 



Loss of weight, 0-7099 1-3227 1-1850 



H..0 per cent., 29-51 29-47 27-42 



Determination of Nickel and Iodine. 



I. II. III. 



Weight of suhstancc, 1-4055 1-0959 0-5669 



NiO, 0-2361 0-1866 — 



Ni, 0-1855 0-1466 — 



Per cent, of Ni, 13-20 13-38 — 



Weight of Agl, — — 0-6087 



Weight of I, — — 0.3289 



Per cent, of I, — — 50-02 



