290 



SCIENCE. 



[Vol. IT., No. 85. 



interest on the extra money invested in the more 

 expensive one. 



Mr. J. D. Barnett's paper, on the anthracite- 

 burning locomotive of America, showed that the 

 cleanliness of this fuel was forcing it into use, not- 

 withstanding that it requires a much larger grate- 

 surface, and has an evaporating efficiency but 

 three-quarters that of bituminous coal at market 

 prices: however, where the railroad-companies own 

 the mines, the market price is no basis for comparison. 

 The anthracite is also heavier to carry, and burns the 

 fire-boxes out twenty to forty per cent sooner. 



Messrs. A. McDonnell and J. A. F. Aspinwall, and 

 W. Stroudley contributed representative papers on 

 English locomotives. The weights of locomotives 

 were given as from twenty-eight to thirty-nine tons, — 

 much less than our own, but capable of great speed, 

 which, however, is now equalled or excelled here. 

 Improvements are rapidly forcing their way into 

 English engines, which are now built in a limited 

 number of classes, with interchangeable parts. 

 Special tools are not used, however, to any extent in 

 their construction, and but little attention is paid to 

 elegance, or to the comfort of the engineer. Inside 

 cylinders are mostly used ; and on one road the driv- 

 ing-wheels are in front, on the supposition that they 

 keep the track better. 



Mr. D. Joy furnished a paper on his reversing and 

 expansion valve gear. This is an arrangement of 

 levers, etc., by which the valve motion is obtained 

 from the connecting-rod instead of from the shaft. 

 It is advantageously used on many locomotives, and 

 has been applied also to marine engines. It makes 

 the connections much shorter and lighter, and avoids 

 the double eccentric. Many other advantages are 

 also shown. 



Mr. J. H. Bartlett's paper on heating buildings by 

 steam from a central source is a most valuable resume 

 of the subject in pamphlet form. It shows, that, 

 prior to 1876, large buildings and even blocks had 

 been heated by steam from a central source; and in 

 many cases steam had been successfully piped long 

 distances. Mr. Holly then suggested the present 

 district plan; and experiments were made which have 

 led to a remarkable development of the system, which 

 were described in detail. Drawings were given of 

 Holly's reducing-valve and regulator, and of his 

 steam-meter; also a plan of the large district in op- 

 eration in New York city. Estimates for a district 

 of four hundred (also a thousand) dwellings, and two 

 miles of main, during two hundred and forty days, 

 were given; and the relative cost given of the in- 

 dividual-furnace, individual-steam, and district sys- 

 tems, — the latter with four hundred, also a thousand 

 consumers, —was $113, $197, $64, $58. The econo- 

 my of elevating the burning of coal into a distinct 

 business must be evident to all ; and there is no bet- 

 ter distributer of heat than steam. To form an idea 

 of the magnitude of the New York company's opera- 

 tions, their plant should be inspected. 



On Monday, papers were read by Mr. W. Smith, on 

 the light-house system of Canada; and by Sir J. 

 Douglass, on improvements in coast-signals. These 



were remarkably well illustrated by nearly one thou- 

 sand square feet of colored drawings, covering the 

 walls, and referring mainly to the new Eddystone 

 light-house. Among these were Winstanley's (1696 - 

 1703, washed away), Rudyerd's (1706-1755, burned), 

 Smeaton's (1755 - 1882, removed to another site), — all 

 of about the same height; and the new light-house 

 nearly twice the height (one hundred and thirty- 

 three feet to lantern). Another drawing reproduced 

 Smeaton's drawing of his light-house with a wave 

 rising fifty feet above it, and added another immense 

 wave which broke over the lantern in 1881, through 

 which the moon was seen. Canada has nearly six 

 thousand miles of coast, with about five hundred 

 light-stations; and Mr. Smith referred to buoys to be 

 placed below Quebec, with reservoirs of gas capable of 

 maintaining a light for ninety hours. He remarked 

 also, that Canada was doing her best to compete with 

 New York for the carrying trade of the west, by im- 

 proving her light-house system. Experiments are be- 

 ing made by the British government on coast-signals, 

 some results of which were given. The electric light 

 was found to have almost no fog-penetrating power, 

 so that only by an immense multiplication of candle- 

 power was it made equal to gas or oil in the worst 

 weather. Its cheapness showed forcibly, however, 

 in a statement that 22,000 times the light could now 

 be had for the cost of the candles of Winstanley's 

 house. A heavy wave was instanced as carrying away 

 a three-hundred-pound bell, a hundred and ten feet 

 above high water. There would seem, however, to 

 be no reason why, with a properly shaped rock to 

 deflect it upward, a wave might not rise to an immense 

 height. A new system of lights and fog-signals was 

 explained by Sir James Douglass, in which signals 

 are repeated every thirty seconds (instead of three to 

 four minutes) ; this is more consistent with the pres- 

 ent speed of vessels, — though, as Sir William Thom- 

 son insisted, much too long a time: a signal should 

 be capable of almost instant recognition. Only red 

 and white lights are used in these ' flashing' signals, 

 and red but sparingly; the signals themselves oc- 

 cupying about ten seconds, and being, in fact, the 

 Morse alphabet with long and short flashes. The 

 French and English governments are doing away 

 with stationary and revolving lights, and introducing 

 flashing ones. Fog-horns with reeds do not stay in 

 order; and a steam siren is to be used, high and low 

 notes being proposed instead of long and short blasts. 



Mr. W. H. Preece read three electrical papers, — 

 The 'watt' and the horse-power; Secondary bat- 

 teries; Domestic electric lighting. Secondary bat- 

 teries are now an accomplished commercial fact in 

 England, the old Faure accumulator being as good 

 a form as any. Domestic electric lighting can now 

 almost compete with gas, which costs in London 

 three shillings per thousand. 



Attention was called to the fact that there is no in- 

 candescent lighting in Canada; and Sir W. Thom- 

 son called attention to the water-power running to 

 waste in the Lachine rapids. A photographic gallery 

 in Regent Street, London, was referred to, where the 

 electric light is used for the negative and for print- 



