Oct. ii, 1883] 



NA TURE 



583 



the report of Sir E. J. Reed on the Daphni disaster, and the 

 discussion which resulted, that naval architects were using the 

 term stability both in its proper sense, as meaning a tendency to 

 hold a particular position, and also as meaning a tendency to 

 change position in a particular direction. The writer of the 

 paper proceeded to urge the desirability of using two terms, the 

 one to express the greatest angle of di turbance from which a 

 vessel would return to her normal position, and to limit the 

 quantitative meaning of the term " stability " to the measure of 

 that angle, using the term "stiffness" to express the moment of 

 the upsetting forces necessary to produce any particular angle of 

 disturbance. The adoption of that system, which was c insis- 

 tent and definite, would prevent the confusion into which it ap- 

 peared naval architects had fallen, and it would then be seen 

 that w hat were ill-called curves of stability would be well-called 

 curves of stiffness. 



On the Construction and Working of Alpine Hail-ways, by J. 

 B. Fell, C. E. — There are three Alpine railways in existence at 

 the present time — the Mont Cenis and .St. Gotbard Hallways, 

 which have been made with long summit tunnels and with ordin- 

 ary gradients, and the Brenner Railway, that has been made 

 with similar gradients but without a long tunnel. The important 

 question has now arisen, and has been taken into serious con- 

 sideration by the Governments and local authorities interested, 

 as to how far it may be possible to make other trans-Alpine 

 railways, some of which are urgently needed, at a cost that 

 would render them financially practicable ; and to accomplish 

 this object it has been proposed to effect a reduction of one-half 

 or more of the cost, by carrying thee rail" ays over the moun- 

 tain passes by means of steep gradients and the use of the centre 

 rail system, as it was adopted on the Mont Ceni-. Railway. 

 Upon these improved summit railways the same weight and 

 number of trains could be run that are now running on the Mont 

 Cenis Tunnel Railway, and with the protection of aval 

 galleries and covered ways the regularity of the service would 

 be maintained at all seasons of the year. The extra cost of 

 working expenses caused by working over a higher level than 

 that of a tunnel line would, if capitalised and added to the cost 

 of constructiou, still leave a clear net saving of more than one- 

 half in the cost of construction as compared with the cost of a 

 tunnel railway. The result of the experiences of the last 

 twenty-five years seems to point to the conclusion that a method 

 of constructing Alpine railways with long, non-paying tunnels is 

 a thing of the past. The future belongs to the best system that 

 can be devised for overcoming the difficulties of trans-Alpine 

 railways rather by adding to the powers of the locomotive 

 engine and by other mechanical appliances for reducing the cost 

 of traction on steep inclines, which methods are capable of 

 indefinite improvement, than by burying in gigantic tunnels 

 enormous sums of unproductive capital that, when once ex- 

 pended, are irrecoverably lo.-t. 



The Euphrates Valley Railway as an Alternative Route to 

 India, by j. B. Fell. — The author described the proposed route, 

 and gave the total cost as 8,500,000/. He stated that, when not 

 only its commercial but also its strategical and political advan- 

 tages were taken into account, it must be admitted that the 

 Euphrates Valley Railway certainly has the prospect of being 

 one of the most successful enterprises in the world. Canon 

 Tristram detailed his experience in the Tigris and Euphrates 

 valleys, and stated that he believed the former to be the prefer- 

 able route. 



On Injector Hydrants, by J. H. Greathead. — This paper 

 described the method proposed for the author for meeting the 

 serious increase of fires in the metropolis. A separate system of 

 water supply at very high pressure would be laid under the foot- 

 way w ith hydrants at short distances apart. The high pressure 

 water would be used in conjunction with the ordinary water 

 supply in the mains, and jets of water would thus be enabled to 

 be raised to sufficient heights without the aid of fire-engines. 

 The paper was illustrated by numerous diagrams, and elicited an 

 interesting discussion, generally favourable to the author's views. 



Nest Gearing, by Prof. Fleeming Jenkin. — This paper con- 

 tained an account of a new friction gearing, the chief novelty 

 being in the mode of obtaining any required amount of pressure 

 between the wheels which roll upon each other. As many as 

 thirty-tw o modifications have already suggested themselves, and 

 the opinions expressed in the discussion were unanimously in 

 favour of the invention as being a very valuable one. 



Electric Launches, by A. Reckenzaun. — The paper commenced 

 with a description of the launch Electricity, which made her first 

 trip in September, 1882. The Electricity is 25 feet long, with a 



5 feet beam, and draws 21 inches forward and 30 inches aft. 

 Her speed is 8-3 miles per hour with ten passengers on board. 

 Forty-five Sell n-Volckmar accumulators stored under the seats 

 and decks forward and aft supplied the current to two Siemens 

 D ;1 Series dynamos placed side by side on the floor of the boat, 

 with their axes parallel to the propeller shaft. A Carliss-Browne 

 two bladed propeller of 20 inches diameter and 3 feet pitch was 

 employed in these first experiments ; straps and pulleys were 

 resorted to in order to reduce the speed of the screw to 350 

 revolutions, whilst the motors revolved at 950 revolutions per 

 minute. The two motors were coupled in parallel circuit, 

 whereas the cells formed one series. Each machine had its own 

 sw itch and ammeter, and the starboard machine could be stopped 

 mechanically by means of a friction clutch on the countershaft. 

 Both machines were tested with a Prony brake, and they gave 

 1*86 horse-power on the brake at 950 revolutions, consuming a 

 current of 21 amperes and 100 volts. At 694 revolutions, too 

 volts and 3325 amperes, the brake horse-power rose to 278. 

 With 47 cells on board, the current used by both motors running 

 together was 46 amperes, and the propeller made 360 revolu- 

 tions ; when disconnecting one of the motors the current passing 

 through the other was 33 amperes, and the speed of the propeller 

 shaft fell to 250. Messrs. Siemens' dynamos lend themselves 

 very readily to the purposes under consideration ; the height of 

 al'j machine is only 10 inches, length 28 inches, and width 23 

 inches. The two machines weigh together 632 lbs., countershaft, 

 supports, and pulleys 180 lbs., total for the driving apparatus 

 S12 lbs. 



Electric Launches, by J. Clark. — This paper contained a very 

 brief account of advances in this subject. 



The Eire Risks of Electric Lighting, by Killingworth Hedges. 

 — The author first drew attention to the great difference 

 between the electric currents which have been in constant 

 use for telegraphic purposes and those which are to be sup- 

 plied by the undertakers under the Electric Lighting Act. 

 The latter can only be said to be free from danger when 

 the heat generated by the current is utilised in its right place, 

 and not developed in the conductors or wires which lead the 

 electricity to the incandescent lamps. The Fire Risk Com- 

 mittee have already issued rules for guidance of users of elec- 

 tric light ; these can hardly be said to embrace all the salient 

 points of the new subject, which can only be arrived at after 

 years of practical work. The necessity of proper regulations 

 has already oeen recognised by the insurance offices, both in 

 the United States and Germany, and some of their special rules 

 are given in this paper. The conductors must be properly pro- 

 portioned for the current they have to carry ; whatever resistance 

 there is in the conductor will cause a corresponding development 

 of heat, which will vary with the amount of electricity passing, 

 and inversely as the sectional area. As the temperature in Dr. 

 Matthiessen's experiments upon the subject was not increased 

 over 100° C, the author has made some further experiments — 

 heating the wires by the electric current from a secondary battery 

 to within a few degrees of their melting-point. Various mate- 

 rials were tried — the wires and foils having such sectional area, 

 and so arranged that, on the current being increased by 20 

 per cent., they were immediately fused. The total length of 

 each experiment was twenty-four hours, during which time the 

 current passing through varied slightly. The results of the 

 experiments were then given. 



SCIENTIFIC SERIALS 



Archives of the Physical and Natural Sciences, Geneva, Sep- 

 tember 13. — Verification of some atomic weights (second 

 memoir) ; zinc and magnesium, by M. C. Marignac. The 

 atomic weight of zinc, fixed by Erdmann at 65*05 and by Favre 

 and Jacquelain raised to 66, is approximately determined at 

 65'33, a figure which further analysis may show to be slightly 

 too low. For magnesium, calculated by MM. Marchand aid 

 Scheerer at 24 and by others at 24'5, the number 24*37 resuls 

 from the author's fresh experiments. — Essay on the protistology 

 of Sardinia, with a description of some new or little-known 

 lower animal organisms, by Prof. Corrado Parona. In the 

 fresh and marine waters of Sardinia the presence is determined 

 of as many as 228 species belonging to the families of Bacteria 

 — Monera, Flagellata, Lobosa, Diatomea, Heliozoa, Ciliata, 

 Acineta, and Catallacta. The paper is accompanied by seven 

 illustrations. — Memoir on earthquakes and volcanoes (continued), 

 by Prof. F. Cordenons. In this second and concluding part the 



