274 



Profs. Liveing and Dewar. 



[Jan. 26, 



Up to the present time, no compounds of chromium with ammonia 

 have been described, which are analogous in composition to those 

 forming the subject of this paper. The metal cobalt, however, forms 

 with ammonia the base of Fremy's well-known series of luteocobaltie 

 salts, to which these compounds bear a marked resemblance. Com- 

 paring the compounds at present analysed with the corresponding 

 luteocobaltie salts : — 



New Series. 

 { (C0^ 3 H 4 ) p Cr 2 }(Cr 3 7 ) 3 3H 2 

 { (CON 2 H 4 ) 12 Cr 2 }(PtCl 6 ) 3 2H 2 

 {(C01Sr 2 H 4 ) 12 Cr 2 }Cl 6 6H 2 

 {(CON 2 H 4 ) 12 Cr 2 }(SO 4 ) 3 10H 2 O 

 {(CON 2 H 4 ) 12 Cr 2 }(N0 3 ) 6 



Luteocobaltie Salts. 

 .. {(NH 3 ) 12 Co 2 }(Cr 3 7 ) 3 5H 2 

 .. {(NH 3 ) 13 Co 3 }(Pt01 6 ) 3 6H 3 O 

 .. {(NH 3 ) 13 Co 3 }Cl 6 

 .. {(NH 3 ) 13 Co 3 }(SO,) 3 5H 3 

 .. {(NH^CoJCNO,), 



Several other compounds are in course of preparation or analysis, 

 and will form the subject of a further communication. 



I am greatly indebted to my friend and former pupil, Mr. C. TV 

 Heycock, B.A., for much valuable aid in the analysis of these compli- 

 cated compounds. 



I desire also to express my thanks to Professor Liveing for much 

 valuable advice and assistance. 



II. " On the Spectrum of Water. No. II." By G. D. Liveing, 

 M.A., F.R.S., Professor of Chemistry, and J. Dewar, M.A., 

 F.R.S., Jacksonian Professor, University of Cambridge. 

 Received January 14, 1882. 



In our former communication on the subject of the water spectrum 

 (" Proc. Roy. Soc," vol. 30, p. 580) we stated that the spectrum we 

 then figured did not by any means exhaust the spectra of flames we 

 had observed, but it was as much as we had at that time been able to 

 trace to water as its cause. We had, in fact, noticed in the spectrum 

 of coal-gas and hydrogen-flames a still more refrangible but less intense 

 series of lines ; and we have since observed that this second series is 

 produced under the same, circumstances as the first, and we therefore 

 ascribe it to the same cause, namely, the incandescent vapour of 

 water. It is easily produced not only by the flames just mentioned, 

 but by the arc of a De Meritens machine when a current of steam is 

 passed into it, and by the spark of an induction coil without jar in 

 moist air or other moist gas. When a large coil and jar are used it 

 almost or wholly disappears. 



The accompanying figure is drawn from a photograph of the 

 spectrum of an oxyhydrogen flame ; and the wave-lengths marked on 



