222 REPORT— 1870. 



quired an imuecessary enlargement of the breech-cliamber ; and tlie common solid 

 brass cartridge-case now in general nse in America and other countries would in 

 many respects be preferable to it, especially because it can be readily obtained in 

 large quantities, because its adoption would leave the chamber of the rifie of a 

 minimum size, capable of being made larger if need should ever aiise, and because 

 the case was not destroyed in firing, and can be filled over and over again, and its 

 use would thus be a source of great pecuniary saving to volunteers in their practice. 



On BoUer-Exj)losions. By E. B. Maetek, C.E. 



At the Exeter Meeting it was suggested, in a report of a select committee, that 

 inquests on boiler-explosions should be improved by making it compulsory that 

 coroners should have scientific witnesses to assist the juries to aScertain the causes 

 of explosions. From considerable experience in such investigations, the writer 

 concluded that much more good would result from publishing independent reports 

 to the Government by competent engineers, without interference with the ancient 

 and useful coroner's inquest ; and that the public would benefit more by the reports 

 themselves than by the verdicts founded on them b}^ juries, who, although well 

 able to decide whether any one was criminally liable for a death, would be quite 

 incompetent to discriminate between conflicting scientific opinion as to the causes 

 of boiler-explosions. 



On the Construction of Seiuers in Running Sand. 

 Bij Messrs. Eeade and GoomsoK, C.E., Liverpool. 



The authors related their experience in the construction of sewers at various 

 places lying on the coast between Liverpool and Southport, a district mostly con- 

 sisting of sand from 10 to 20 feet deep, thoroughly permeated with water and rest- 

 ing on a bed of moss and marl. In some places in the driest seasons the water- 

 level is only a few feet below the surface. The difficulty of laying the inverts of 

 the sewer true is innnensely increased by the low gradients demanded by the 

 general flatness of the coimtry. They generally use fireclay pipe-sewers, from 

 motives of economy and other reasons ; and the jointing of these is very difficult in 

 reaming sand, in consequence of the cement, even when covered with a clay lute, 

 getting washed into the sewers before it has time to set. To overcome these 

 difficulties they have introduced a subsoil-drain and pipe-rest (manufactured by 

 Messrs. Brooke and Sons of Huddersfield) of tlie form of the letter ca, which is 

 laid first in the bottom of the trench and jointed with clay like an ordinary pipe- 

 sewer. This has the efiect of lowering the subsoil-water, so that the sewer proper 

 can be laid upon the moveable saddles or rests (fitting the curvature of the drains 

 and the sewers) undistm'bed by water or reaming sand. By these means the 

 cement joints can be made perfect all round, and ha^'e time to set before the trench 

 is filled up. True gradients are insured, as the pipes can be leisurely laid ; and as 

 the pipes are jointed over the middle of the subdrain a continuous foundation is 

 secured. A more perfect drainage of the subsoil is also found to result, the gene- 

 ral level of the water being reduced to nearly the level of the invert of the sewer. 

 They have begim to use the subsoil-drains in the sewerage works they are carrying 

 out at Birkdale, which includes a length of 10,000 yards of pipe-sewers. Methods 

 for flushing the sewers with the subsoil-water were also described, and all the ap- 

 paratus used by the authors in similar sanitary works. 



On an OUiqiie Proj^elhr. By Professor Osborne Reynolds. 



Paddles for propelling ocean-steamers have been displaced by the screw ; the 

 gi'eat advantage of which is that it does not interfere with the saihng-qualities of 

 the ship to the same extent as paddles do. It has, however, many disadvantages, 

 as is shoAvn by the frequent accidents which hai^pen to screw-steamers. These are 

 all due to its position at the end of the boat. Thus, it interferes with the action of 

 the rudder, it makes the ship vibrate, it will not act when the ship is pitching. 



