Jar.. 6, 1888.] 



SCIENTIFIC NEWS. 



19 



ROYAL SCOTTISH SOCIETY OF ARTS. 

 The secretary, Mr. Lang, read a report on the "Correction 

 of the Ship's Compass." At the outset he explained 

 that the Society's Committee had reponed regarding a 

 compass by IVIr. Moore, of Belfast, that they were in 

 favour of his plan of attaching to the C0|n! pas'- bowl, instead 

 of to the deck or sides of the binnacle, the magnets and 

 iron that corrected the deflector action of ,the iron in ships, 

 and that it was an improvement in compass adjustment. 

 Some correspondence arose from this, Sir William 

 Thomson in a letter expressing disapproval of the theory 

 which Mr. Moore advocated. Sir William said it would 

 bring discredit on the Society of Arts to act on, or to give 

 currency to, a grave theoretical error. Mr. Lang then 

 entered into a defence of the position taken by the 

 society. Mr. W. Bottomley, assistant to Sir William 

 Thomson, maintained that magnets fixed to a ship's 

 binnacles should remain parallel and perpendicular to 

 the deck. When the ship heeled over the correction of 

 the heeling error was entirely lost by attaching the 

 quadrantal correctors to a bowl hung on gimbals. A 

 serious and dangerous fault in the plan of attaching 

 correctors to the bowl was the nearness of the correctors 

 to the compass needles. 



ROYAL BOTANIC SOCIETY. 

 At the last meeting of this society, Mr. J. P. Gassiot, 

 Vice-President, in the chair, the secretary made some 

 remarks upon the Oiterciis coccifera, or Kermese oak, and 

 the dye-insect from which its name is derived, specimens 

 of both being exhibited at the meeting. A common plant 

 upon the shores of the Mediterranean, it has been from 

 the most ancient times celebrated as the source of a very 

 rich crimson dye, which until the discovery of the 

 cochineal insect in America, was held in high estimation, 

 and formed an important article of commerce, but is now 

 almost entirelj- unknown, even in those places where it 

 was formerly collected. Some interesting examples of 

 the hardening of the constitution of plants by exposure 

 were also exhibited, suggesting the inference that plants, 

 like animals, are capable of being acclimatized. 



INSTITUTION OF CIVIL ENGINEERS. 

 The paper read on 6th December was " Electrical Tram- 

 vVaj'S : the Bessbrook and Newry Tramwaj'," by Edward 

 Hopkinson, M.A., D.Sc. Although a number of electrical 

 tramways had been constructed in the United Kingdom 

 during the last few years, there had hitherto been no 

 attempt at the regular haulage of minerals and goods, nor 

 at the operation of cars larger than the ordinary tramway 

 type. Probably in no case had the effective power of 

 nny single motor exceeded about four horse-power. The 

 principal object of the present paper was to describe the 

 fonstruction and to discuss the working of the Bessbrook 

 md Newry Electrical Tramwaj', which had been designed 

 "or the haulage of heavy goods as well as for passenger 

 raffic. The length of the line was rather more than three 

 miles, with an average gradient of one in eighty- six, the 

 maximum gradient being one in fifty. According to the 

 conditions of the contract, ten trains were to be run in 

 ;ach direction per day, providing for a daily traffic of 100 

 tons of minerals and goods, and capable of dealing with 

 200 tons in any single day, in addition to the passenger 

 traffic. It was worked entirely by water-power, the 

 generating station being adjacent to the line at a distance 



of about one mile from the Bessbrook Terminus. There 

 were two generating dynamos of the Edison-Hopkinson 

 type, driven by belting from the turbine-shaft. The 

 turbine could develop sixty-two horse power, and each 

 dynamo was intended for a normal output of 250 

 volts, 72 amperes, though they were capable of 

 giving a much larger output. The current was con- 

 veyed to the locomotive cars by a conductor of steel, 

 rolled in the channel form, laid midway between the rails, 

 and carried on wooden insulators nailed to alternate 

 sleepers. At one point the line crossed the county road 

 obliquely, the crossing being 150 feet in length. In 

 this case the conductor on the ground level was not 

 feasible, and an overhead conductor on Dr. John Hop- 

 kinson's system was substituted, by which the collector 

 on the car consisted of a bar only, which passed under 

 the supports of the overhead wire, and made a rubbing 

 contact with its under surface. This system had been 

 found to give very satisfactory results in practice. The 

 trains were commonly composed of one locomotive car 

 and three or four trucks ; but frequently a second pas- 

 senger-car was coupled, or the number of trucks increased 

 to six. Thus a gross load of thirty tons was constantly 

 drawn at a speed of six or seven miles per hour, on a 

 gradient of one in fifty. The cars could be reversed by 

 reversing the current through the motor without change 

 of lead, but as there was a loop at each end of the line, 

 reversal was only required when shunting in the sidings. 

 The author concluded the paper with a discussion of an 

 extended series of experiments to determine the efficiency 

 of the whole combination under various conditions, and 

 the distribution of the losses. Under average conditions 

 of working the total electrical efficiency was shown to bo 

 727 per cent., the losses being distributed thus : — 

 Loss in generator . . . . 8-6 per cent. 



„ leakage. . . . . . K■^ 



„ resistance of conductor 6'6 „ 



„ motor . . . . . . y-y 



The friction of the bearings in both generator and motor, 

 and the power lost in the driving-gear, were excluded 

 from these results. 



In an appendix to the paper the cost of the electrical 

 equipment of the line was summarised, and the cost of 

 haulage per train-mile was shown to have been 3-31^. 

 over one period of five months, when the goods traffic 

 was light, and 4-2d. when the goods traffic was heavier. 

 Since the opening of the line, the locomotive-cars had 

 registered a train-mileage of 40,000 miles, the tonnage 

 had exceeded 25,000 tons, and the number of pas- 

 sengers iSo,ooo. 



GEOLOGICAL SOCIETY. 

 On November 23rd, 1887, the following communications 

 were read : — 



1. "Note on a New Wealden Iguanodont, and other 

 Dinosaurs." By R. Lydekker, B.A., F.G.S. 



2. "On the Cae-Gwyn Cave." By T. McKenny 

 Hughes, M.A. The subject fell into two divisions : The 

 Age of the Drift outside the Cave, and The relation of 

 the deposits in the cave to that Drift. The author con- 

 tended that the drift outside the cave was of approxi- 

 mately the same date as the St. Asaph drift ; and he 

 discussed various difficulties, stratigraphical and palseon- 

 tological, in the way of accepting the view that the cave- 

 deposits were glacial, interglacial, or preglacial. For 

 instance, he remarked that there were no marks of 

 glaciation on the face of the rock in which the cave 



