210 REPORT— 1869. 



Tn order to ascertain tlie action of this description of buffer -witli high velocities, 

 some experiments were made, and described iu tliis paper. They consisted in al- 

 lowing a truck loaded with various weights to run down an incline plane, so as to 

 attain a velocity from 10 feet to 44 feet per second, with which initial velocity the 

 piston was driven through the water. 13y means of a rotating-drum fixed above 

 the cj'liuder, and a pencil attached to the piston-rod, a curve was obtained from 

 which the velocity of the piston-rod during the whole of its motion can be deter- 

 mined, and a formula obtained for calculating the various dimensions of the buffer 

 required for any impinging weight, at any velocitj^ 



The smoothness and ease with which a body mo'sang at a velocity of 44 feet per 

 second (or thirty miles an hour) was brought to rest renders it probable that this 

 description of buffer may be found useful for many purposes, especially as a sta- 

 tionary ))ufier on railway's. 



On certain Economical Improvements in ohtaining Motive Power. 



By E. Eatox. 

 [For Abstract of this Paper, see Appendix.] 



On Government Action ivith regard to Boiler Explosions. 

 By LiTiNGTOJr E. Fletcher. 



On the Hydraulic Internal Scrapinr/ of the Torquay Water-main. 

 By R. E. Feotjde. 



Torquay is supplied with water from Dartmoor by a cast-iron main 13J miles iu 

 length, and having an aggregate fall of .370 feet between the inlet and the outlet 

 at the standard reservoir. The diameter for the first eight miles is 10 inches, for 

 the remainder 9 inches, an intermediate town drawing a regulated supply fit the 

 point of change. In 184.3, six years after the opening of the work, the delivery, 

 which appears from the first to have been defective, was found to be barely half 

 what the recognized formulas promised. 



The defect was attributed to internal oxidation ; but as this, though forming a 

 rough carbuncular surface, did not much exceed i- of an inch in average thick- 

 ness, the obstruction would have been insignificant according to the commonly re- 

 ceived view, that the water detained in the roughnesses would furnish a smooth 

 surface for the internal column to glide through ; and it followed that either the 

 received view needed some con-ection, or that local obstructions must ha's e been 

 established by accumulations of sediment or otherwise in the many deep depressions 

 of grouud-surfiice traversed by the main. 



Under the directions of Mr. "W. Froude a novel and effective test was debased and 

 employed for the determination of this question. 



A very delicate and accurate pressure-gauge was applied to the main, at short 

 and selected intervals throughout its length ; a method of drilling the necessary 

 holes and fitting the connecting taps, without emptying the main, having been con- 

 trived, which prevented any escape of water during the operation under the heaviest 

 pressures. 



Colmuns of water equivalent to the pressures thus tested were calculated : and 

 the heights of these being laid down on the section of the line of main, at the 

 positions of the several gauge-stations, or, in other words, being added to the datum- 

 lieights of those stations, the resulting elevation of the column-summits were found 

 to form, for the 10-inch and 9-inch pipes respectively, perfectly uniform gradients, 

 showing that in each the consumption of pressure per mile was also uniform 

 throughoiit, and that there could be no local obstructions. 



The incrusted oxide thus appeared to be the only known cause of obstruction ; 

 and the late Mr. Appold, with characteristic acuteuess and boldness, suggested 

 that it would be possible to force a suitably constructed scraping implement, along 

 the main internally, by the existing hydraulic pressm-e, so as to remove the incrus- 

 tation. 



