594 Meeting of the British Association. [Oct., 



to coat the recipient of the deposit with a thin film of nickel or 

 copper. 



The Committee on the Chemical Nature of Cast Iron reported 

 that they entrusted the preparation of pure iron to Mr. Matthiessen, 

 who expressed a hope that next year a great deal of very useful 

 information will be obtained on the chemical nature and physical 

 properties of pm-e u'on and its alloys. Prof. Matthiessen then 

 detailed very elaborately the nature and properties of pure iron, 

 and the best methods for its preparation and fusion. 



Professor Calvert, in some remarks upon the series of experi- 

 ments conducted by him into the nature and condition of rust, 

 stated that he thought the oxidation of the bottom of iron ships 

 might be prevented by an external coating of an alloy of lead and 

 antimony, and by placing an alkah in the bilge- water within the 

 vessel. 



Professor Tomlinson read a paper on the supposed Action of 

 Light on Combustion. From a series of experiments ujjon candles 

 of different sizes and weights in dark chambers and day and sun 

 hght, it was found that the increase of temperature alone led to 

 increase of consumption of material ; the final conclusion being 

 that the direct hght of the sun, or the diflused light of day, has no 

 action on the rate of burning, or in retarding the combustion of an 

 ordinary candle. 



Mr. Walter Weldon read a long paper " On the Manufacture 

 of Chlorine by means of perpetually regenerated Mauganite of 

 Calcium." What has hitherto been the ordinary process of manu- 

 facturing chlorine, consists in digesting ores containing peroxide of 

 manganese with hydrochloric acid. The chloride of manganese, 

 which is a residual product of this process, has hitherto been 

 ordinarily thrown away. Mr. Weldon decomposes this chloride of 

 manganese by lime, and then blows air through the resulting 

 mixture. The protoxide of manganese absorbs oxygen from the 

 injected air, thereby becoming converted into peroxide, which com- ' 

 bines with the equivalent of lime used in excess, forming therewith 

 the compound which the author calls manganite of calcium. The 

 compound thus produced is employed instead of manganese ores for 

 the liberation of chloriue from hydrochloric acid, and is then re- 

 produced from the resulting solution of chloride of manganese, and 

 so on continually, the same manganese being thus employed over 

 and over again perpetually. Last year there were made in this 

 country, and on the Continent, about 120,000 tons of bleaching- 

 powder, and this bleaching-powder costs on an average about 5/. 

 per ton for native oxide of manganese. Mr. Weldon's process 

 produces bleaching-powder at a cost of only 15s. per ton for 



