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Show H POPULAR SCIENCE g Prevents Railway Accidents. Many serious street car accidents are caused Ly the premature starting of the car by the motorman, who may be totally unaware of the entrance to or exit from the car of a passenger who suddenly decides to get on or oil as it is about to start. It is the sudden sud-den turning on of the electrical current, cur-rent, with the consequent danger to a person on the car step, that William H. Caley of Denver, Colo., seeks to prevent by the mechanical device shown in the drawing. The purposes of the device are: First, to provide an automatic means by elevating the eyes until the line of vision is above the frame of the semi-oval semi-oval lenses. This feature makes it almost unnecessary to remove the supplemental lenses at all, as the wearer has the advantage of both the long-distance and near vision without with-out either set of lenses interfering with the other. The inventor is Moses H. Cohen of Marseilles, 111. Uses of Iron and Steel Slag. The most important of the uses of slag is the manufacture of structural material, and especially hydraulic cements. The production of the six or eight slag-cement establishments in ' 1901 amounted to 272,689 barrels; and two plants are making Portland cement from slag and limestone. The highly phosphatic slags produced In basic Bessemer converters are valuable valu-able fertilizers. Mineral wool is also largely derived from slag; though about one-half of that sold is made from natural rocks of different types. In 1901 3,500 tons of mineral wool were made from slag in the United States. In the year about 5,000 tons of slag were used in constructing macadam highways in various states, and these have proved entirely satisfactory. satis-factory. Telephone on Locomotive. The cause of nearly all the train wrecks on the railway lines of the country is the severing of all connection connec-tion between the train crew and dispatcher dis-patcher while the trains are in motion, and, while the automatic signal apparatus appar-atus now in operation on some of the roads has done much to insure the safety of railway travel, there is no doubt that the telephone recently patented pat-ented by Alva D. Jones of Louisville, Ky., would still further minimize the loss caused by these accidents. This inventor claims to have solved the difficulty dif-ficulty of maintaining a contact through the trolley device running on the telephone wire which parallels the Automatic Safety Device. for maintaining the car stationary until persons entering or leaving have cleared the steps and are thus out of the dangerous position; second, to provide a mechanism to prevent any increase of speed while a person Is on the steps, even though such person mounted while the car was in motion, thus guarding against any increase of the risk which the passenger assumes when mounting the steps; third, to provide a positive means to enable the conductor to prevent the motor-man motor-man from starting the car when danger dan-ger arises out of the range of vision of the latter. The apparatus is a simple one, comprising com-prising a ratchet wheel located on the shaft of the controller, with a pawl engaging the teeth to prevent rotation in one direction while the steps are depressed by a person's weight. Placing the foot on the step of the car operates a lever to drop the pawl and guard against turning on the power without interfering with the cutting off of the current if it is partially par-tially or wholly applied to the motor. The Colors of the Sky. The tendency to refer to electricity all phenomena not otherwise explainable explain-able is perhaps illustrated in the theory the-ory advanced by M. Wing at the recent re-cent annual meeting of the Swiss Academy Aca-demy of Natural Science that the color of the atmosphere, usually called the "blue" sky, i due to such cause. This azure tint has hitherto been ascribed to the refraction of light on minute particles of solid matter suspended in the air. M. Wing has made a number num-ber of experiments with luminous rays injected into numerous solutions containing con-taining suspended matter, and, though he has easily obtained red, violet and yellow tints, he was only able to get blue by the use of electricty, and then he was able to obtain it in a perfectly pure atmosphere. He, therefore, concludes con-cludes that the blue color is an essential essen-tial quality of the air and due to electricity. elec-tricity. Improvements in Spectacles. To those persons whose eyes are so constituted that separate pairs of spectacles must be worn for viewing objects near at hand and at a distance, dis-tance, the invention shown herewith may prove interesting, while its use might perhaps save expense and guard against misplacement of the Traveling Contact of Novel Form. railway line," &M ir-sffM fee-rE twisting.. to note his method of overcoming t what has hitherto been considered an . almost insurmountable obstacle to the '". use of a locomotive telephone. While the weight of the trolley is carried on. the wheel in the casing, a sliding contact con-tact in the form of an absorbent pad is the intermediary through which the current reaches the receiver in the cab. This pad is kept moistened by a jet of steam derived from the boiler, which passes first through a body of soluble chemicals, such as common salt or saltpeter, of such a character as to increase the conductivity of the pad. An adjustable support pivoted on the side of the cab carries a rod, on the upper end of which the casing surrounding the contact device is mounted, and it is possible to contract the whole apparatus beneath the cab j window when the engine is not out on J the road. A Sensitive Thermostat. A thermostat of extreme sensitiveness sensitive-ness is described in the Journal of Physical Chemistry (vol. 6, p. 118) by Messrs. Bradley & Browne. It consists con-sists of a glass bell jar containing water stirred by a propeller and regulated' regu-lated' in temperature by the inflow of warm water from a second metal thermostat ther-mostat heated by gas and roughly regulated by a small alcohol expan- sion regulator with a mercury cut-off of the type described by Ostwald. The inflow of warm water is also controlled con-trolled by a similar regulator. The body of each of these regulators consists, con-sists, of a long spiral tube only five ,. ,. millimetres in diameter which in- ' sures a very rapid response to tern- i perature changes. ... , j, Scientific Jottings. Typhoid germs die after a few days' ' exposure in sea water. j A dinner cooked by electricity costs ten cents, a breakfast two cents.-" Yarn made from wood pulp is now an article of commerce in Germany. Sarah C. Bagley of Lowell, 1846,. was the first woman telegraph operator. Dr. Biilinkin of Epernay, France, J has produced complete insensibility I during important surgical operations by high frequency alternating electri- cal currents. j W. J. Spillman, agrostologist for the-' United States Department of Agriculture, Agricul-ture, is preparing a map of the United States made of plants, to be exhibited at the St Louis exhibition. - For . Near and Distant Objects. extra pair of glasses when one pair was being worn. In using this device it is only necessary for the' wearer to purchase a pair of spectacles , for viewing distant objects, this pair being of any ordinary " make and either adapted to be held in place by the earguards or by gripping the bridge of the nose. The supplementary supplement-ary frame containing the lenses for reading or looking at objects close at hand' is so formed that it can be attached' at-tached' to the ordinary ,frame, suspending sus-pending the semi-oval lenses either in front of or behind the original pair. The supplemental frame has hooks to engage the outer ends of the main frame, to aid the bridge in supporting the weight of the lenses and maintaining main-taining them in close contact with the main lenses The wearer is then enabled to read with ease by looking through the double lenses, and at the same time can view distant objects |