Just now, when so many are devoting their time and attention to the various means of transportation, trying to discover the quickest way of moving us mortals from one place to another over both the land and the sea; when steam, electricity, petroleum, benzine, etc., have entered the lists against the muscles of the horse, {nd even of human beings, we are sure that our readers will he interested in the motor shown in the accompanying engravings, for which we are indebted to the mustrirte Zeitung. This boat is propelled by a screw driven by foot power, and is operated by three people, the one nearest the stern also steering. The wheel visible behind the last operator transmits motion to the shaft and through the latter to the propeller. By various arrangements of the three cranks dead centers can be avoided. For every 60 movements of the treadles the screw revolves 500 times. In this way even unskilled operators can travel about five miles an hour. A great advantage of this boat is that it can also be propelled by oars or sails, and the simple apparatus can be applied to any boat that is sufficiently broad. As the three operators sit quite high, a counter weight of lead should be placed in the keel. The Najork boat has created quite a sensation in boating circles. -m % - The Chicago Police Telephone Sy.te_. Chicago has a complete telephone and signal system, consisting of 887 public and 370 private boxes, operating on 81 circuits, connected with the 37 precinct stations of thb department, in which they are located. The system includes public sentry boxes placed at street interseetions, equipped with a signal hox to transmit the number of the station; a telephone for patrolmen to report and receive orders over; a chemical register at the station which records the calls, and the necessary switches for operating the telephone and testing for electrical disturbances. Silver from Sliver Oro_Ide. Silver is usually recovered from silver bromide wastes, incident to photographic processes, by mixing them with nine-tenths their weight of calcined sodiul carbonate, and fnsing in a crucible, whereby carbon dioxide and oxygen are given off. Metallic silver gathers at the bottom of the crucible, and a double 1 salt of sodium carbonate and sodium bromide floats on top as a clear liquid. On cooling the crucible down to a red heat the silver solidifies, and the flux, still in a liquid state, may then be easily poured off. The silver thus obtained is of a fine white color. The flux usually has an intense yellow color and still contains about 10 per cent of silver. The latter may be obtained (Pharm. Centralh., xxxvi, p. 632) by mixing the flux with plenty of water and stirring occasionally to facilitate solution of the flux. The unchanged silver bromide is allowed to settle, washed by decantation, and preserved for a subsequent operation. hi Sulphur Milling in Louisiana. The Mineral Collector says: The Standard Oil Company has finally solved the great problem, on which hundreds of thousands of dollars have been spent in vain, of getting at the immense mass of sulphur which lies some hundreds of feet below the surface in Calca-sieu Parish, Louisiana. For thirty-five years company after company has experimented with this deposit of sulphur, which is probably the largest ill the country, and is valued at from $30,000,000 to $100,000,000. There was no doubt about the sulphur being there, but unfortunately between it and the surface lay an immense quicksand, which could not be removed, excavated or bored through. There was no way of man reaching the sulphur and getting it up. A small town, Sulphur City, has grown up in the neighborhood of the mines, at which lived the operatives engaged in trying to solve their problem. As the expenses of these em ! ployes had to be paid, and as not a pound of sulphur s was obtained, the several companies organized to mine ! it went, one after another, into bankruptcy, until the property fell, a short time ago, iuto the hands of the great Standard Oil Company. Long before the discovery of petroleum in Pennsylvania a party of hunters stumbled on a petroleum spring in Calcasieu. The Louisiana Petroleum Com-I pany was organized to mine for it, and while mining discovered that side by side with the oil was one of ! the most valuable deposits of nearly pure sulphur in ; the world. The sulphur was 400 feet below the sur-, face and extended below 800 feet further. There was , no doubt or question about this, but, unfortunately, just above the sulphur was a auicksand 160 feet thick. I One effort after the other to reach the sulphur failed. i The drill struck an undergroulld well, then a gas well. After several deaths the American Sulphur Company gave up the enterprise. Then a Belgian engineer undertook the work and endeavored to neutralize the quicksand by freezing it solid and boring it through, and erected valuable refrigerating machinery for that purpose, but the quicksand would not stay frozen and that system of mining had to be abandoned. Within the last few weeks the Standard Oil Company has got control of the property. It set about mining in a fashion the very opposite to that of the Belgian engineer. Instead of using freezing as (he means of getting at the sulphur, it is trying heat. Superheated water is forced through ten inch pipe on the sulphur, melting it, and the liquid sulphur water is then pumped up. A little exposure to the air, so as to evaporate the water, leaves almost pure sulphur. The experiment has been a success beyond expectations.