SCIENTIFIC NEV^^S. 



[Nov. 1st, 1 5 



large, the managers decided to run the mill for the next two 

 years night and day. For this reason artificial lighting be- 

 came necessary, and on account of the great danger from 

 explosions, no other than the electric light could obviously 

 be used. The work has been carried out by Messrs. B. 

 Egger and Co., of this town, and comprises fifty-one glow 

 and four arc lamps, the latter being two in series and burn- 

 ing parallel with the glow lamps. All the mains, switches, 

 fusible plugs, and branch wires are carried on the outer 

 walls of the building, and the lamps are placed in niches in 

 the walls, the apertures towards the illuminated rooms 

 being guarded by double glass windows with water filling. 

 The niches communicate with the outside by ventilating 

 pipes, which serve as channels for the wires, and keep the 

 temperature low. The dynamo is compound wound, and 

 has an output of 65 amperes at no volts; it is driven at 

 1,000 revolutions by a Girard turbine. 



Writing Telegraph. — According to Nature, a highly in- 

 genious modification of Cowper's writing telegraph has 

 been shown at the American Exhibition by Mr. J. H. 

 Robertson, an American electrician. The movement of a 

 pen at the sending station varies the resistance of two elec- 

 tric circuits along which two currents are flowing. These 

 varying currents act upon two coils at the receiving station, 

 so as to impart motion in two directions to a pen filled with 

 ink, so that the resultant motion of this pen exactly repro- 

 duces the movement of the writing pen at the sending sta- 

 tion. Mr. Robertson has replaced Mr. Cowper's resistance 

 coils by a series of thin carbon discs, which vary their re- 

 sistance with variation of pressure, as was discovered by 

 Edison and utilised in his carbon telephone transmitter. 

 He has also improved the receiving portion, and has made 

 the apparatus very practical. It is being commercially 

 worked out in the United States, and we shall watch its 

 progress with much interest. It forms a really beautiful 

 system of written messages, and is decidedly simpler than 

 any previous system of facsimile telegraphy. It is very 

 doubtful whether there is a demand for such a system, for 

 the operation is necessarily slow. 



Match-making. — Nearly all the operations of match- 

 making are now carried on by machinery. The wood is 

 first sawed into blocks of uniform length, usually one and a 

 half inches long, or the length of the match. These blocks 

 are then fed into the cutting-machine, which cuts twelve 

 matches at every stroke. To make round matches, the wood 

 is forced through perforations in metal plates. The slints 

 are then pushed into slats arranged on a double chain 250 

 feet long. On this they are carried to the sulphur vat, 

 dipped therein by a mechanical movement, and then, in the 

 same manner, to the phosphorous vat and dipped. Machines 

 are also used for making the boxes and packing the slints 

 therein. As the consumption of matches is most enormous 

 — being estimated at six a daj' for every man, woman, and 

 child in Europe and North America — they form an impor- 

 tant article of commerce, and the invention of machinery 

 for their manufacture has proved of great advantage. But 

 the especial value of machinery is that it has so largely re- 

 duced the mortality caused by working over the phos- 

 phorous. The substance, when heated, throws off fumes 

 which cannot be continuously breathed without causing 

 disease. In large factories 144,000 small boxes of matches 

 are often made and packed ready for shipping in a single 

 day. 



Great Engineering Project. — One of the most prodigious 



engineering projects now on the tapis is that for tunneling the 

 Rocky Mountains under Tray's Peak, which rises no less 

 than 14,441 feet above the level of the sea. It is stated 

 that at 4,441 feet below the peak, by tunneling from east 

 to west for 25,000 feet direct, communication could be 

 opened between the valleys on the Atlantic slope and those 

 on the Pacific side. This would shorten the distance be- 

 tween Denver in Colorado and Salt Lake City, Utah, and 

 consequently the distance between the Missouri River, say 

 at St. Louis and San Francisco, nearly 300 miles, and there 

 would be little more required in the way of ascending or 

 descending or tunneling mountains. Part of the work has 

 already been accomplished. The country from the Missouri 

 to the foot of the Rockies rises gradually in rolling prairie 

 until an elevation is reached of 5,200 feet above the sea 

 level. The Rockies themselves rise at various places to a 

 height exceeding 11,000 feet. Of the twenty most famous 

 passes, only seven are below 10,000 feet, while five are 

 upward of 12,000, and one is 13,000 feet. The point 

 from which it is proposed to tunnel is sixty miles due west 

 from Denver, and, though one of the highest peaks, it is by 

 far the narrowest in the great backbone of the American 

 Continent. 



A Development in Newspaper Industry. — We learn 

 from The Yorkshire Post that its method for promptly re- 

 ceiving news have been materially added to by the laying 

 down of a pneumatic tube between the offices of The York- 

 shire Post and the Postal Telegraph Department. Instead 

 of the enormous number of telegrams which are nightly 

 received at their offices being delivered by messengers, they 

 are now shot through the ipneumatic tube from the post- 

 office in ten seconds. The tube consists of a lead pipe of 

 i|-inch bore and about 750 feet long, and extends from the 

 instrument-room of the Postal Telegraph Department to the 

 receiving table in the sub-editor's room, and is encased in a 

 strong cast-iron protecting pipe, which is laid under the 

 pavement, and passes along Park Row, Bond Street, Basing- 

 hall Street, and in at the back of the printing-offices. For 

 the purpose of conveying the messages, a small cylindrical 

 vulcanite " carrier," covered with cloth and fitted with a felt 

 flange or pad at one end, so as to completely fill the aper- 

 ture of the pipe, is provided. When the signal has been 

 received from the post-office that a carrier has been placed 

 in the pipe, a valve is opened at the receiving end, and the 

 air in the tube having been exhausted by a steam-engine, 

 the message speeds on its way at the rate of about seventy 

 feet per second, and is finally delivered upon the receiving 

 table. 



Electrification of Air. — According to the Electrical 

 Revieiv, Mr. R. Nahrwoldt has made a series of experiments 

 on the gradual loss of electricity of electrified bodies. In an 

 essay published in 1878 the author proved that the discharge 

 takes place by means of the particles of dust suspended in 

 the air. These are electrified and then repelled from the 

 electrifying body. The result of these experiments led 

 Lodge and Von Obermayer to their method of clearing rooms 

 from smoke. Later on, it was shown that a wire of platina 

 made red-hot by electricity electrified the surrounding air, 

 although it was almost free of dust. For this reason Nahr- 

 woldt resumed his experiments. He found that electricity 

 was discharged through a point only in dusty air. He 

 made his experiments in an air-tight glass shade, the sides 

 of which were covered with a thin layer of glycerine. After 

 the dust was precipitated on the sides of the glass through 

 the action of the electricity, the discharge was very slight. 

 As soon as the wire of platina was electrified, and became 



