TRANSACTIONS OF SECTION B. 613 



in general chemistry over and beyond what it has been customary to teach takes 

 too much time is met by the consideration of the fact that some portion of the 

 descriptive matter usually given in lectures may be cut olT, not with inconvenience, 

 but rather with advantage, inasmuch as in the class-room the attention of 

 students should be more directed to points of general interest and importance, 

 whilst the time usually devoted to analytical work in the laboratory may also be 

 conveniently shortened, what the student should learn from it being rather 

 principles and methods of atnalysis than mere practical skill. 



2. On the Detection and Estimation oy Arsenic in Beer and Articles 

 of Food. By W. Thomson, F.R.S.E. 



3. On the Nomenclature of the Ions. 

 By Professor James Walker, F.R.S. 



4. On the Equilibrium Law as applied to Salt Separation and to the 

 Formation of Oceanic Salt Deposits. By Dr. E. Frankland Arm- 

 strong. — See Reports, p, 262. 



5. Report on the Bihlioyraphy of Spectroscopy.— See Reports, p. 155. 



WEDNESDAY, SEPTEMBER 18. 



The following Papers were read : — 



1. The Electrolytic Conductivity of Halogen Acid Solutions. 

 By Dr. J. Gibson. 



2. On the Ilame Coloration and Spectrum of Nickel Compounds. 



By P. J. Haetog. 



It was shown that when nickel acetate is brought into a Bunsen flame together 

 with hydrochloric acid two kinds of coloration may be produced : (1) a temporary 

 purple coloration which flashes out and disappeais; (2) a more permanent deep- 

 red coloration. The temporary coloration is so evanescent that the spectrum of 

 bright lines to which it gives rise could not be mapped by the eye. It is hoped 

 to record it photographically. The deep-red coloration gives with a single prism 

 spectroscope two bands — a red band, extending from wave length 6292 to G126, 

 and a green band, extending from 5328 to 5290. It was shown by spraying a 

 10 per cent, solution of nickel acetate into a Smithells separator that the colora- 

 tion is produced in the inner cone. The solution must be eitlier mixed with 

 hydrochloric acid or chloroform vapour must be introduced into the flame in the 

 manner used by Smithells in his researches on flame coloration. Nickel chloride 

 introduced into the flame gives only a slight red coloration. Cobalt acetate was 

 found to yield no flame coloration. 



The theory of flame coloration is still obscure, despite the researches of 

 Pringsheim and Smithells ; but these experiments lend support to the view that 

 chemical action is necessary for the production of colour in the flame. It was 

 pointed out that in the case of manganese the flame coloration (green) said to be 

 ' sometimes ' produced can always be produced with the acetate. 



1901. s s 



