276 Prof. A. Gamgee. Absorption of the extreme [Feb. 13, 



that when the Rontgen rays pass through a dielectric they make it 

 dnring the time of their passage a conductor of electricity, or that 

 all substances when transmitting these rays are conductors of electricity . 

 The passage of these rays through a substance seems thus to be ac- 

 companied by a splitting up of its molecules, which enables electricity 

 to pass through it by a process resembling that by which a current 

 passes through an electrolyte. By using a block of solid paraffin in 

 which two pairs of electrodes are embedded, the line joining one pair 

 being parallel, that joining the other pair perpendicular, to the 

 Rontgen rays, which were kept passing through the block, I found 

 that there is but little difference between the rate of leakage along 

 and perpendicular to the rays. 



I have much pleasure in thanking Mr. J. A. McClelland, of Trinity 

 College, Cambridge, and Mr. E. Everitt for the assistance they have 

 given me in carrying out these experiments. 



A telegram from Professors Borgman and Gerchun, of St. Peters- 

 burg, forwarded by the editor of the ' Electrician,' to the effect that 

 Rontgen rays discharged electricity, and a letter from Professor 

 Lodge to the effect that he had definitely ascertained that the phos- 

 phorescent glass was the source of the radiation of Rontgen rays, and 

 that the radiation starts in all directions, and not normally only from 

 the glass, were read. 



IV. " On tbe Absorption of the extreme Violet and ultra -Violet 

 Rays of tbe Solar Spectrum by Haemoglobin, its Com- 

 pounds, and certain of its Derivatives." By Arthur 

 Gamgee, M.D. ; F.R.S., Emeritus Professor of Physiology 

 in the Owens College, Victoria University. Received 

 February 11, 1896. 



In the year 1878 the late Professor J. L. Soret, of Geneva, in his 

 first memoir on the absorption of the ultra-violet rays of the spec- 

 tram by diverse organic substances,* announced the fact that diluted 

 blood, when examined with the aid of a spectroscope provided with 

 a fluorescent eye-piece, presented in the extreme violet, between 

 Fraunhofer's lines G and H, an absorption band which appeared to 

 him to be slightly shifted towards the less refrangible end of the 

 spectrum when the blood solution was saturated with carbonic 

 oxide. Soret subsequently! confirmed the accuracy of the above 



* J. L. Soret, " Pecherches sur 1' Absorption des Rayons ultra-violets par diverges 

 Substances," 4 Archives des Sc. Phys. etNat,,' vol. 61 (G-eneva, 1878), pp. 322—359. 

 t Soret, ' Archives des Sc. Phys. et Nat.,' vol. 66 (1883), pp. 194, 195, and 204. 



