Sept. 1st, 1887.] 



SCIENTIFIC NEWS. 



149 



these experiments, a dog which was placed on scales in a 

 heated chamber lost in one hour eleven grammes of water 

 per kilogramme, or fi per cent, of its own weight. 



A Novel Clock. — A clock has recently been patented in 

 France in imitation of a tambourine. A circle of flowers, 

 corresponding with the hour figures of ordinary dials, is 

 painted on the parchment, and there are two bees, one 

 large and the other small, which crawl about among the 

 flowers. These bees take the place ofthe ordinary clock hands, 

 one of them running quickly from flower to flower and com- 

 pleting the circle in an hour, while the other bee moves 

 more slowly and takes twelve hours to complete the circle. 

 The bees are in no way fastened to the parchment, the 

 surface of which is unbroken, but inside the tambourine 

 there are two magnets connected with suitable clockwork, 

 and the bees being made of iron they naturally follow the 

 magnets. 



Compressed Air for Electric Lighting. — According to 

 Industries, a Company has been formed in Paris for the \ 

 supply of compressed air to users of dynamo machines 

 for electric lighting. A central station has been provided 

 where engines of 3,000 aggregate horse-power will com- \ 

 press the air for this purpose. The mains are already 

 being laid, and the work is being pushed on with all pos- | 

 sible speed to furnish motive power to the theatres within 

 the time allowed by the Government order for the substi- ( 

 tution of electric I'ght for gas. With electric lamps and 

 compressed air engines, it is believed the maximum of safety 

 from fire will be attained, and it is added that the scheme 

 is to be extended to the provinces, and that Lille will pro- \ 

 bably be the first town to adopt it. 



Conversion of He.\t into Electricity. — We learn from 

 Italy that Messrs. Hurghausen and Nerust have devised a most 

 curious experiment from the scientific point of view. After 

 placing a thin metallic leaf in a magnetic field, they found that 

 if its extremities were maintained at uneven temperatures, 

 there was a difference of potential at the two ends — ex- 

 tremely slight, it is true, but quite appreciable. Moreover, 

 the direction of the current varied with the lines of force 

 ofthe magnetic field. They used a piece of bismuth five 

 centimetres square and two millimetres thick, and' the 

 difference of temperature was obtained by placing two 

 pieces of mica in contact with the ends of the bismuth, one 

 ofthe pieces of mica being immersed in cold water, and the 

 other heated by a spirit lamp. 



The Telephone assists the Telegraph. — It was at one 

 time urged that an extended use of the telephone might be 

 prejudicial to the telegraph, but the reverse is actually the 

 case, and the number of messages sent to telegraphic offices 

 by means of the telephone is very considerable. In Belgium 

 special facilities are given for this purpose to telephone sub- 

 scribers, and according to statistics just published it appears 

 that during the first five months of the present year 167,838 

 telegrams were transmitted in this way on the Brussels, 

 Antwerp, Liege, Charleroi, Ghent, Vervieis, and Louvaise 

 lines. This is an increase of no less than 37 per cent, over ' 

 the number sent in the corresponding period of 1S86, and 

 throughout Belgium it is estimated that there is an average 

 of 1,200 telegrams per day which are transmitted by tele- 

 phone. 



The Panama Canal. — The Scientific Atitcricaii says that 

 in all probability this work will shortly be stopped, and 

 that the projectors are considering the really formidable 

 problems on the solution of which the completion of the 

 work depends. It is alleged that it is not only essential to 

 control the torrents which at certain periods pour down the 



mountain sides, and which, if unchecked, will render the 

 maintenance of the canal impossible, but that provision 

 must also be made against a mountain which is actually 

 moving slowly into the very path of the canal ! Our con- 

 temporary adds that the deadliness of the climate and the 

 important difference between the mean level of the two 

 oceans have also to be considered, so that it is not surprising 

 if the engineers in charge are unable to discover practical 

 means of accomplishing their purpose. 



Detection of Hot Bearings. — According to Industries, 

 M. Gerboz has devised an apparatus by which an audible 

 and visible signal is given to the engine-driver if any part 

 of the machinery to which the apparatus is fitted becomes 

 unduly hot. In its simplest form, as applied to the crank 

 pin of a steam engine, the device consists of a small cylin- 

 der fastened to and projecting from the crank pin, and 

 containing a plug of easily fusible alloy, which is pressed 

 against the end of the crank pin by a perforated piston and 

 spring. The piston rod controls a catch belonging to the 

 mechanism of a bell placed over the apparatus, and the gear 

 of the bell, which is actuated by spring power, is previously 

 wound up by hand and locked by the catch. If the crank 

 pin should heat, the fusible plug melts, thus allowing the 

 piston to descend, thereby releasing the catch and sounding 

 the bell. 



A Stone in a Hailstone. — The presence ol solid sub- 

 stances has often been noticed in melted snow and hail, 

 but never before has a stone weighing two grammes 

 been found in a hailstone. We learn, however, from 

 La Nature that such an occurrence has actually been 

 proved by M. Tissandier, and that not only was 

 the stone enclosed as thick as an ordinary sized 

 thumb, but it had evidently been worn down to its present 

 shape. The substance was not analysed, because the stone 

 would have been spoilt, but it appeared to consist of gypsum 

 (sulphate of calcium); it is easily scratched, it is not affected 

 by acids, and its specific gravity is 23. This singular 

 stone fell at Tarbes during a violent storm, and it is sup- 

 posed that it had been carried up into the clouds by a 

 whirlwind, and that there it became a centre of attraction 

 for particles of ice. 



Metallic Cement for Stone. — The following metallic 

 cement for repairing broken stone was, according to Professor 

 Brune, of the School of Fine Arts, used in the restoration ot 

 the colonnade of the Louvre, of the Pont Neuf, and of 

 the Conservatoire des Arts et Metiers. It consists of a 

 powder and a liquid. The powder — Two parts by weight 

 of oxide of zinc, two of crushed grit, the whole intimately 

 mixed and ground. Ochre in suitable proportions is added 

 as a colouring matter. The liquid — A saturated solution 

 of zinc in commercial hydrochloric acid, to which is added 

 a part, by weight, of ammonium chloride equal to one-sixth 

 that ofthe dissolved zinc. This liquid is diluted with two- 

 thirds of its bulk of water. To use the cement, one pound 

 of the powder is mixed with two and a half pints of the 

 liquid. It is said that the cement hardens very quickly, 

 [ and is very strong. 



Heating Railway Carriages by Hot Water.— Mr. W. 



Foulis, of Glasgow, who has invented several useful appa- 



I ratus heated by gas, has lately introduced a system for 



: heating railway carriages by the waste heat from the gas 



lamps used to light the roofs of the carriages. This is effected 



by means of water, a boiler being placed over the gas lamps, 



having two pipes descending from it, and connected with 



! two tubes under the carriage seats. The hot water cir- 



' culates through these pipes and returns again to the boiler 



