The next illustration is more marvelous, and seems to indicate that some species, at any rate, have the power of movement through the air in any direction at will.
Some years ago, at a dinner party in Kent, four candles being lighted on the table, I noticed a thread strung from the tip of one of the lighted candles close to the flame, and attached to another candle about a yard off; and all the four lights were connected in this way, and that by a web drawn quite tight. No little surprise was caused among the guests on finding that the diamond form of the web was complete.
No satisfactory explanation of this has been offered, and I can only suggest that the spinner was suspended at first by a vertical line from above, and thus swayed itself to and fro, from tip to tip of the candles. It was certain that the spider could not have ascended from the table; and it was equally certain that aerial flotation of the line from a fixed point was impossible, as it involved floating in four opposite directions. I have seen a creature of this or a nearly allied species moving laterally through the air of a room in this way.—Knowledge.
ENGINEERING NOTES.
Austria is turning out a new variety of Mannlicher repeating rifle for its army, which is the lightest rifle in the world, weighing 3.3 kilogrammes, seven pounds and four ounces, instead of 4.4 kilogrammes, nine pounds eleven ounces, the weight of the old pattern. All the individual parts in the new rifle, including the locking box, the magazine and the barrel, are lighter than in the old. The bayonet and sheath are also made lighter.
A trolley express car system is now in successful operation in Brooklyn, N.Y. The trolley system of Brooklyn is one of the most extensive in the world, and many of the outlying districts are now served with great dispatch. Parcels are collected by wagons, they are then brought to the cars, and, after being carried to the nearest express station to their destination, they are then transported again by wagons. On Sundays the cars are run to carry bicycles.
In Stanislau oil gas is being a good deal used for incandescent lighting, says the Gas World. The gas is used at a pressure of from 1.1 in. to 1.2 in. When 1.7 cubic feet per hour is used the Welsbach mantle gives 69½ candles at first, 65 candles after 120 hours, 48¼ candles after 500 hours. The fall in lighting power is comparatively slow with oil gas, and the mantles are not so much worn by lighting the gas, for the kind of oil gas is not as explosive as that of coal gas. The mantles are found to last from 400 to 600 hours.
During the construction of the Simplon tunnel every possible alleviation will be made for the workmen employed, says the Railway Review. On leaving the tunnel when they are hot and wet through they will go at once to the douche and bathrooms provided for their accommodation, where, after a refreshing shower bath, they will resume their dry clothes. The sheds from which the workmen leave the tunnel are to be covered in and closed at the sides so as to protect them from cold. Water will be taken at intervals to the workmen who may require it, either from the pipe which feeds the drills or from that which brings water for cooling. No provision has been made as regards workmen's lodgings, because it is supposed that they will easily find accommodation in the neighborhood. As it is believed that the temperature of the rock of the Simplon tunnel may reach a maximum of 104° F., costly measures will have to be taken to cool the air in many parts where the works are to be carried on.
"Recent Developments in Lighthouse Engineering" was the title of a paper read recently at the Institution of Civil Engineers, by Mr. N.G. Gedye, says the Colliery Guardian. The author pointed out the marked development which has of late years taken place in the direction of reducing the length of flash emitted by lighthouse apparatus to a minimum, and the consequent increase obtained in intensity. The apparatus now being erected at Cape Leeuwin, Western Australia, gives a flash of one-fifth of a second duration every five seconds. It is the most powerful oil light in the world, the flash being over 145,000 candle power emitted from a pair of dioptric lenses mounted on a mercury float revolving once every ten seconds. Each of the two lenses is 8 feet in diameter. The powers of these oil lights are far exceeded by electric lighthouse lights, there being several in France up to 23,000,000 candle power, while there has recently been established at Fire Island, at the entrance to New York Harbor, an electric light, of French design and construction, of 123,000,000 candle power; this is the most powerful lighthouse light in the world.