342 



On the new Gas obtained from Uraninite. [Mar. 19, 



additional confirmation of his results. I have found that when turacin 

 is treated with strong sulphuric acid, the resulting turaco-porphyrin 

 presents in the extreme-violet an intense absorption band, which in 

 position and characters is identical with that of haematoporphyrin, 

 obtained by the action of concentrated sulphuric acid or pure hsematin 

 hydrochloride. In solutions of extreme dilution, this band occupies 

 the space between h and H. If the solution be slightly more con- 

 centrated K is absorbed, and with increasing concentration of the 

 solution the absorption of the ultra-violet extends more and more. 



Dr. Archibald Garrod and Mr. Glowland Hopkins, who first brought 

 under my notice Professor Church's researches on turaco-porphyrin, 

 have communicated to me the results of their own observations, 

 which show that alkaline solutions of turaco-porphyrin exhibit, in 

 respect to the absorption bands in the visible spectrum, slight differ- 

 ences from haematoporphyrin — though the identity of the spectrum 

 of acid solutions of the two bodies is complete. The facts which I 

 have placed on record in this paper point, however, to the essential 

 identity of turaco-porphyrin and haematoporphyrin, and when taken 

 in connection with the identity of the ultra-violet spectrum of turacin, 

 and of the acid haematin compounds, appear to me to establish that 

 turacin contains the atomic group, which is the cause of the charac- 

 teristic extreme violet and ultra-violet absorption exerted by haemo- 

 globin, its compounds, and principal derivatives. 



VIII. " On the new Gas obtained from Uraninite. (Seventh 

 Note.) Remarks on Messrs. Runge and Paschen's Diffu- 

 sion Experiment." By J. Nokman LOCKYER, C.B., F.R.S. 

 Received March 14, 1896. 



I pointed out in a previous communication* that, from evidence 

 afforded by the behaviour of the lines under different conditions of 

 the spark, the gas obtained from cleveite is in all probability com- 

 pound. 



Some time afterwards (July 11, 1895) Messrs. Runge and Paschen 

 publishedf the same conclusion, and, as a result of a diffusion experi- 

 ment:]: described in their paper, they came to the conclusion that the 

 gas giving the line D 3 was heavier than the gas giving the line 5015*7. 

 As they themselves, however, pointed out, the result was not final, 

 because the pressures were not the same. As it is important for 

 stellar classification to settle this matter, I have recently made some 

 experiments in which the pressures remain the same. The experi- 



* ' Roy. Soc. Proc.,' vol. 58, p. 193. 



f ' Sitz. der X. Preus. Akad. der Wiss. zu Berlin,' vol. 34, 1895. 

 X ' Nature,' vol. 52, p. 321. 



