xxii Proceedings. {^April jth, igio. 



Barnard, of the Yerkes Observatory, which showed very clearly 

 the peculiarly twisted form of the comet's tail. 



Mr, R. L. Taylor read a paper entitled "A Preliminary 

 Note on the Action of Carbon Dioxide and of Air on 

 Bleaching Powder and similar substances." 



Contrary to what is generally supposed, carbon dioxide, in 

 presence of moisture, liberates no hypochlorous acid from 

 bleaching powder, either solid or in solution, but only chlorine. 

 Similarly, carbon dioxide liberates nothing but bromine from a 

 mixture of a bromide and a hypobromite. When air, freed from 

 carbon dioxide, is passed through a solution of bleaching powder, 

 it slowly sweeps out hypochlorous acid, which is present in the 

 free state in the solution, being produced by the action of water 

 on the calcium hypochlorite. If, however, moist air containing 

 the usual small amount of carbon dioxide is passed through 

 bleaching powder, either solid or in solution, a mixture of 

 chlorine and hypochlorous acid is given off, the chlorine usually 

 largely predominating. In the case of the solid substance, after 

 the moist air has been passed through for a considerable time, 

 and the bleaching powder has thus become quite wet, there is 

 no hypochlorous acid produced, but only free chlorine. 



When bleaching powder, mixed with about thirty times its 

 weight of water, is heated with boric acid, practically pure 

 hypochlorous acid is given off, no matter what proportion of 

 boric acid is used. This forms a convenient method of preparing 

 a solution of hypochlorous acid. Under similar conditions, a 

 mixture of a bromide and a hypobromite evolves nothing but 

 bromine. 



Annual General Meeting, April 19th, 19 10. 



Mr. Francis Jones, M.Sc, F.R.S.E., President, 

 in the Chair. 



The Annual Report of the Council and the Statement of 

 Accounts were presented, and it was resolved: — "That the 



