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Registering compass
262
Notes a n d Comments.
[J. F. I.,
tograph. These varyiug currents pass t h r o u g h the line and are received in a moving coil galvanometer the pointer of which, in moving, inserts or takes out resistance in a h i g h tension circuit, according as t h e current flowing in the moving coil changes. In t h e high tension circuit a small vacut~m tube is emaneeted, and it follows that the illumination of this tube is proport~onaI to t h e light passing t h r o u g h the plate at the transmitting end of t h e line. This vacuum tube now passes over the sensitized photographic paper in synchronism with the ray of light over the transmitted plate, and thus a reproduction of the same is obtained. The t r a n s m i t t e d film and sensitized paper are each wrapped on a glass cylinder. These cylinders are rotated by motors, and synchronized once each revolution. Only one wire is needed for the transmission, with, of course, an earth return. In the ease of the transmission of h a n d w r i t i n g and half-tone illustrations, the same are got up on metal foil with electrical non conducting ink. A conducting point t h e n travels over the metallic foil, and d o s e s and opens the sending circuit according as it is traveling on a m a r k e d or an unmarke t place. The receiver used by the author is a modification of that described above, the essential point b e i n g the use of the Vacuum tube fed with the Tesla currents. The speed reached is 5oo written words per hour. For a halftone illustration a strip ~ centimeter wide aud Io centimeters 10ng can be sent in ~oo seconds. It would seem that there is not very m u c h practical value in the t r a n s m ' s sion of handwriting; t h e t y p e - p r i n t i n g telegraph of to-day fulfils all ordinary requirements, and it would be only very seldom that a trans.alission of handwriting would be required. It is to be hoped, however, that this electrical " distant p h o t o g r a p h y " will make rapid progress. R E G I S T E R I N G COMPASS. A compass which automatically registers minute by minute has been p a t e n t e d by M. Heit, a French inventor. The compass card is fixed cn a steel pivot, which rests on a fixed agate, instead of having at its center an agate resting on a fixed steel point. The fixed agate is immersed in a drop of mercury, which serves as a conductor for the e~ectrie current that causes t h e m o v e m e n t s 6t" registering. By the use of lhis instrumetrt it is elaimed that a ship's officers have a complete record of a voyage. F E R R O - C O N C R E T E R A I L W A Y TIES. Some interesting tests are being made on the railroad between Voiron and Saint B~ron, in France, with ferro-concrete in lieu of wooden railroad ties, to ascertain the comparative initial and m a i n t e n a n c e cost, efficiency and durability of these two systems. This track is 3 feet 3 inches gauge, and the ties are 3"9 feet long by 7 inches wide and 5 ~ inches deep. They weigh 23 pounds each, and cost approximately ~o cents each. T h e concrete used is composed in the proportion of 33 kilograms of cement to 4o liters of sand, and the reinforcement of steel bars weighs 8'4 kilograms per tie. Under the most unfavorable conditions, it is even considered t h a t the first cost of the ferroconcrete ties will not exceed that of good oak ties more than in the proport:on of 5 to 3, ~ h i l e it will be four or five times as durable.--Scientific American.
Notes a n d Comments.
[J. F. I.,
tograph. These varyiug currents pass t h r o u g h the line and are received in a moving coil galvanometer the pointer of which, in moving, inserts or takes out resistance in a h i g h tension circuit, according as t h e current flowing in the moving coil changes. In t h e high tension circuit a small vacut~m tube is emaneeted, and it follows that the illumination of this tube is proport~onaI to t h e light passing t h r o u g h the plate at the transmitting end of t h e line. This vacuum tube now passes over the sensitized photographic paper in synchronism with the ray of light over the transmitted plate, and thus a reproduction of the same is obtained. The t r a n s m i t t e d film and sensitized paper are each wrapped on a glass cylinder. These cylinders are rotated by motors, and synchronized once each revolution. Only one wire is needed for the transmission, with, of course, an earth return. In the ease of the transmission of h a n d w r i t i n g and half-tone illustrations, the same are got up on metal foil with electrical non conducting ink. A conducting point t h e n travels over the metallic foil, and d o s e s and opens the sending circuit according as it is traveling on a m a r k e d or an unmarke t place. The receiver used by the author is a modification of that described above, the essential point b e i n g the use of the Vacuum tube fed with the Tesla currents. The speed reached is 5oo written words per hour. For a halftone illustration a strip ~ centimeter wide aud Io centimeters 10ng can be sent in ~oo seconds. It would seem that there is not very m u c h practical value in the t r a n s m ' s sion of handwriting; t h e t y p e - p r i n t i n g telegraph of to-day fulfils all ordinary requirements, and it would be only very seldom that a trans.alission of handwriting would be required. It is to be hoped, however, that this electrical " distant p h o t o g r a p h y " will make rapid progress. R E G I S T E R I N G COMPASS. A compass which automatically registers minute by minute has been p a t e n t e d by M. Heit, a French inventor. The compass card is fixed cn a steel pivot, which rests on a fixed agate, instead of having at its center an agate resting on a fixed steel point. The fixed agate is immersed in a drop of mercury, which serves as a conductor for the e~ectrie current that causes t h e m o v e m e n t s 6t" registering. By the use of lhis instrumetrt it is elaimed that a ship's officers have a complete record of a voyage. F E R R O - C O N C R E T E R A I L W A Y TIES. Some interesting tests are being made on the railroad between Voiron and Saint B~ron, in France, with ferro-concrete in lieu of wooden railroad ties, to ascertain the comparative initial and m a i n t e n a n c e cost, efficiency and durability of these two systems. This track is 3 feet 3 inches gauge, and the ties are 3"9 feet long by 7 inches wide and 5 ~ inches deep. They weigh 23 pounds each, and cost approximately ~o cents each. T h e concrete used is composed in the proportion of 33 kilograms of cement to 4o liters of sand, and the reinforcement of steel bars weighs 8'4 kilograms per tie. Under the most unfavorable conditions, it is even considered t h a t the first cost of the ferroconcrete ties will not exceed that of good oak ties more than in the proport:on of 5 to 3, ~ h i l e it will be four or five times as durable.--Scientific American.