STERILIZATION 



185 



ing powder solution of the same strength in available chlorine, 

 except that in the bacterial tests the two, for some unexplained 

 reason, were not found to act exactly alike. 



The standard strength of Hermite solution was 0*5 gramme 

 of available chlorine per litre. When dilute it rapidly dete- 

 riorated, but this defect has now been overcome. 



More recently Dr. Alexander, at Poplar, has installed a plant at 

 the municipal electricity works, and now uses the Hermite fluid 

 for all disinfectant purposes in the district, including street 

 watering. 



About 1895 Woolf introduced in America, for water purifica- 

 tion, a liquid similar to " Hermite," called " Electrozone," 

 obtained by electrolysing brine containing 2 or 3 per cent. NaCl, 

 or sea water. In 1897 ^ plant was erected for supplying the 



Eliquid to the sewage of Maidenhead, England (after previous 

 precipitation with " ferrozone " and filtration through 

 '* polarite "), i part being added to from 400 to 600 of 

 effluent. In an examination of the process in 1898, with Pro- 

 fessors Robinson and Kanthack, I found that the solution had 

 the properties of sodium hypochlorite, with chloride, the 

 available chlorine being 0*355 P^^ cent., or practically deci- 

 normal ; and that although the treated sewage gave at the out- 

 fall a blue reaction with potassium iodide and starch, showing 

 excess of the reagent, the amount of organic matter was hardly 



fieduced. On the other hand, the bacterial examinations 

 proved that the germicidal action was very marked, so that 

 ^' an effluent nearly colourless, free from odour, and containing 



ivery few bacteria," was left. The electrozone process has been 

 discontinued at Maidenhead, but it was subsequently employed 

 (July, 1899) at Havana, Cuba, for streets, sewage, and harbour, 



[reports stating that it kept the city practically free from yellow 



:fever, and that the cost of generating was 50 cents per 1,000 



fgallons.^ 



Lately I have had a further opportunity of investigating the 

 application of oxy-compounds of chlorine to sewage treatment 

 at the Guildford Sewage Works.^ The electrolytic chlorine 

 used in these tests were generated from brine in a special 



iform of electrolyser owned by the " Oxychloride " Company, 



(which claims certain economic advantages over the earlier types 



! of apparatus. 



^ Electricity, New York, November i, 1899. 



^ Journal of the Royal Sanitary Institute, vol. xxvi , No. 7, 1905. 



