730 REPORT— 1902. 



Although America has lagged somewhat hehind the Continent in adopting 

 large gas engines, there is evidence that this state of aifairs will not long continue. 

 The Snow Steam Pump Works of Buffalo, New York, have only recently' started 

 the manufacture of gas engines, yet they have already put to successful work six 

 gas engines of 1,000 h.p. each, and are now constructing two enormous gas-engine 

 gas compressors of 4,000 h.p. each, the first to be running next November, and the 

 second by January 1903. The Westinghouse Machine and Manufacturing Company, 

 of Pittsburgh, have made gas engines of 1,500 h.p., and are prepared to build sizes 

 up to 3,000 h.p., either horizontal or vertical. 



Improvements in construction were then dealt with, the points touched upon 

 being concerned respectively with the framework, the cylinder and piston, the 

 valves, ignition apparatus, governing devices, and self-starting mechanism. 



Types of engines were briefly considered with a view to show upon what lines 

 the development is progressing, and to indicate the kind of machine which may 

 be expected to prove the most successful gas engine in the future. 



Some advances in the theory of the gas engine were mentioned. The last few 

 years have shed some light on what takes place in a gas-engine cylinder, and the 

 author referred to the questions of temperature gradients, the effect of increased 

 specific heats of gases at high temperatures, and the effect of high pressures on the 

 mode of heat transference to the cylinder walls. The heat efficiency of gas engines 

 received attention, and some figures were given as to the relative efficiencies of gas 

 and steam engines. 



Gas Engi7ies for Cetitral Stations. — It is admitted that the future of gas 

 engines for central-station purposes depends on the ability of gas engines to drire 

 alternators in parallel. Numerous instances were given in which gas-driven alter- 

 nators are regularly at work in parallel, giving good results. The permissible 

 cyclic variation of gas engines intended for driving alternators was discussed, 

 and other matters relating to successful parallel working were dealt with. 



FRIDAY, SEPTEMBER 12. 

 The following Papers and Report were read : — 



1. Steam Turbines. By Hon. C. A. Parsons, F.R.S. 



2. Ueport on the Resistance of Road Vehicles to Traction. 

 See Reports, p. 314. 



3. On Regular Undulations 'produced in a Road by the Use of Sledges. 

 By Vaughan Cornish, D.Sc, F.G.S., F.C.S., F.R.G.S. 



On the steep road from the Saddlestone Slate Quarry, Coniston, Lanes, 

 sledges are used to convey the slate down to the railway, the load for a sledge 

 being half a ton. On the up journey the empty sledge is placed in the cart, to 

 which on the down journey it acts as a drag, so that the sledges are only dragged 

 in one direction, viz., downhill. The sledges produce undulations of a symmetrical 

 and rounded form, resembling a curve of sines, in the road. The length of the 

 sledge-runners is 4 feet 7 inches. The average length of the undulations from 

 crest to crest was, in September 1901, 14 feet 8 inches, and in August 1902, 

 14 feet 9'4 inches, i.e. a little more than three times the length of the sledge. The 

 average height from trough to crest of a series of seven ridges, measured in 1902, 

 was 7'5 inches. Identical sledges are used on part of the road from Cove Quarry, 

 on another side of the hill (the ' Old Man ' of Coniston), which also produce undu- 

 lations, the average length of which was 14 feet 9 inches. Sledges have been in 

 use on the Saddlestone Quarry road for forty years, and it has not been found 



