246 REPORT — 1872. 



in consequence of the property gases have of diffusion. In order to create a draught, 

 Archimediau screws worked by the wind above have been tried, but ventilation is 

 most required when the air is cakii. Fans worked by the current of water below 

 might be used, but the worst smells are given off when the current is least. 

 Burning the gases has been suggested ; but earburetted hydrogen, one of the sewer 

 gases, is highly inflammable, and coal-gas has been found to escape from the gas- 

 mains into the sewers. Explosions might result ; and, in fact, an explosion did 

 result from an experiment tried by Mr. H. Austin, O.E. The same argument may 

 be employed against the proposal to create a draught by jets of coal-gas in the 

 shafts. 



The situation of the outfall is especially suited for sewage-irrigation, and the suh- 

 gtratum being chalk, subsoil drainage would not be required. 



The Distribution of Pure Water to Dwellings. 

 By Alexander M^Calltjm Gordon, of Liverpool. 



This paper served to introduce a comparatively new description of piping called 

 Haines's Lead-encased Block-tin Piping, and pointed out the advantages it offered 

 over ordinary lead pipe as a medium for the conveyance of water throughout 

 dwellings. 



This piping consists of two distinct tubes, an outer one of lead suiTOunding or 

 encasing an inner one of pure tin, both being united at their surfaces of contact as 

 to form a perfectly homogeneous body, and thus offering the admirable physical 

 qualities of a lead pipe together with absolute freedom from the danger of lead- 

 poisoning by reason of the innocuous nature of the tin composing the inner pipe. 



The lead-encased tin pipe was shown to be no more expensive than leaden pipe, 

 as the extra strength gained by the superior tenacitj' of the tin, and certain condi- 

 tions which operate in its manufacture, allows of a diminution of the weight per 

 lineal measurement for a given pressui'e. The piping had already been adopted in 

 many public institutions and private mansions throughout the kingdom, and when 

 better known is likely to take the place of the dangerously poisonous lead pipe 

 now so universally in use. 



On Boat-lowering Apparatiis. By E. J. Hni,, 



On Wire Tramways. By C. Hodgson. 



These consist of an endless wire rope travelling over horizontal drums, one at 

 each extremity of the distance to be traversed, supported and running over pulleys 

 fixed on posts or piers at intervals. The buckets for holding the minerals or other 

 goods for transport are suspended on the rope and travel with it, in such a 

 manner as readily to pass over the pulleys and avoid contact with the posts. It 

 appears well adapted for the transport of goods, and especially minerals, in districts 

 where roads or ordinary tramways are not available. A working model of the 

 wire tramway was shown at the conclusion of the meeting to the members of the 

 Section, at Messrs. C. & J. Reed's foundry, North Road, Brighton. 



Estimation of the Error in the Flight of Heavy Projectiles due to the 

 Woolwich System of Rifling. i>y W. Hope, V.C. 



On tlie Measurement of Waves*. By C. W. Merrifield, F.B,S., Principal 

 of the Royal School of Naval Architecture. 



The writer was induced to look into this matter in consequence of a question 



put to him by Mr. Francis Galton as to whether it was possible to an-ive at any 



* Printed in full in the ' Engineer ' newspaper for 23rd August, 1872, vol. xxxiv. p. 119. 



