800 REPORT— 1895. 



5. On the Deodorising of Sewage hy the ITennite Process. 

 By J. Napier, F.C.S., Public Analyst for County of Suffolk. 



This process consists of passing an electric current obtained from a dynamo 

 throujrli sea water or a solution containing magnesium and sodium chlorides, 

 whereby a portion of the chlorides is converted into hypochlorite, a substance 

 which disinfects, deodorises, and bleaches similarly to the active ingredient of 

 bleaching powder, viz., calcium hypochlorite. This solution is called the 

 electrolised or 'hermlte' solution, and may contain from half to one gramme of 

 active chlorine per litre. 



The author gives a brief liistory of the sewering of Ipswich during the last 

 twenty years, showing the present system, particularly the position of the main 

 sewer as it passes through the town to the outfall. 



The deodorising ell'ects of the electrolised (hermite) solution on sewage, espe- 

 cially upon that in the main sewer of Ipswich, are dealt with, and the results of 

 trials made in August and September 1894 and in June, July, and August of this 

 year are given. 



The installation was at full work during the meeting of the Association. Those 

 interested in the ele.^trolysis of sea water and its effects on sewage were invited to 

 visit the works. 



MONDAY, SEPTEMBER 16. 



The following Papers were read : — 



1 The Modern Application of Electricity to Traction Purposes. 

 By Philip Dawson. 



Introductory. — Sketch of progress made during the past decade; introduction 

 of the under-running trollev and earth return ; adoption of electrical motive power 

 by the West End Street Railway of Boston, U.S.A., in 18S8 ; in 1890, 2,523 miles 

 of electric tramways in America ; rapid increase in mileage and equipment in the 

 United States ; statistics and financial statement ; first prominent!}' successful line 

 in Europe at Halle, Germany, in 1891 ; statement of present European installations 

 and of electrical tramway construction now under contract. 



General and Descriptive. — The especial adaptability of electric traction to 

 tramways and light railways ; but three methods of electrical power transmission 

 practicallj' employed: (1) by elevated conductors with trolley contact ; (2) by sub- 

 surface conduit — contained conductors — and (3) by surface or third rail conductors ; 

 the former by far the most efficient and successful and in most extensive use ; ob- 

 jections to the overhead wire and compensating advantages. 



Parts of an Electric Tramway Installation. — Latest machinery apparatus and 

 methods of construction. 



(a) Power, Plant. — Approved engines, dynamos, and accessories ; general usa 

 of compound-wound machines ; direct coupled generators for large units ; impor- 

 tance of automatic circuit breakers ; power required ; reserve ; utilisation of 

 accumulators. 



{l>) Motors and Gearing. — Specific requirements for exacting service ; general 

 design ; results of tests. 



(c) lleyulation and Control. — Construction and operation of the series parallel 

 controller ; its economy as contrasted with former methods ; speed regulation. 



{d) Motor Trucks. — Essential points of construction ; four-wheel, bogie, and 

 radial trucks ; safety appliances ; brakes, fenders, sand-boxes, lightning ar- 

 resters, &c. 



(e) Trolleys. — For cai's with and without roof seats, and for varying methods 

 of trolley-wire suspension ; wheel and scraping contacts ; modern pivotal trolleys. 



(/) Overhead Line. — Description of material employed ; poles, trolley-wire, 



