Democratic Sentinel, Volume 17, Number 32, Rensselaer, Jasper County, 25 August 1893 — POPULAR SCIENCE NOTES. [ARTICLE]

POPULAR SCIENCE NOTES.

Wonderful Malleability of Gold. —Gold is so very-itenacious that a piece of it drawn into a wire less than the onetwentieth of an inch in diameter will sustain a weight of 500 pounds. The surface of any given quantity of the metal may be extended by the hammer 310,184 times, and each single grain may be divided into 2,000,000 visible parts. The thickness of a piece of gold when extended by the hammer until its surface is 310,184 times its original area is not more than the 566,020 th of an inch! Eight ounces of this wonderful metal would gild or plate a wire of sufficient length to extend entirely around the globe. A Queer Product of Coal Tar.— Saccharin, a coal tar product, discovered within the past few years, is, in several respects, the most favorable of the many odd materials found in coal. First, it is the sweetest known substance. One-half pint of it in 35,000 pints of water will give the water a sweet taste equal to one part of cane sugar in 230 parts of water; a solution of one pint of saccharin and 2500 gallons of water is intensely sweet. In appearance this sweetest of the sweets is not unlike pulverized loaf sugar, being a pure white crystalline powder. Its scientific name is benzoyl sulphonic amide.

A Locomotive’s “Cough.”— The cough or puff of a railway engine isdue to the abrupt emission of waste steam up the stack. When moving slowly the coughs can, of course, be heard following each other quite distinctly, but when speed is put on the puffs come out one after the other more rapidly, and when eighteen coughs a second are produced they cannot be separately distinguished by the ear. A locomotive running at the rate of nearly seventy miles an hour gives out twenty puffs of steam every second—that is, ten for each of its two cylinders.

Repairing an Ocean Cable.—lt has always been a matter of speculation and wonder to most people as to how a marine cable once broken in midocean is ever got together again, says a writer in the New Orleans Times-Democrat. The explanation is this: First, it must be known that the cable practically rests everywhere on the bottom of the sea. Of course there are places where sudden deep places coming between shallow ones will cause the cable to make a spanas over a ravine or gully. In other places the ocean is so deep that the cable finds its specific gravity somewhere in midwater, so to speak. In that case it rests quite as firmly as if it were on solid ground. When a break occurs the first step, of course, is to accurately locate its position. A conductor such as a cable offers a certain amount of obstruction or “resistance” to the passage of an electric current. Apparatus has been devised for the measuring of the “resistance.” The unit of resistance is called an ohm. The resistance of the average cable is, roughly speaking, three ohms per nautical mile. Resistance practically ceases at the points where the conductors make e contact with the water. Therefore, f when measuring to locate a break it be found that the measuring apparatus indicates a resistance of 900 ohms the position of the fault will be known to be 300 miles from shore. With this information the captain of the repairing ship is able to ‘determine by his charts of the course of the cable, the latitude and longitude of the spot where the break occurred, and can proceed with certainty to effect the repair. When the approximate neighborhood of the track is reached a grapnel is dropped overboard and the vessel steams slowly in a course at right angles to the run of the cable. On the deck of the ship there is a machine called a dynometer, which, as its names implies, is used to measure resistance. The rope securing the grapnel passes under this. If the dynometer records a steady increase of strain it indicates that the grapnel has caught the cable. If, on the other hand, the resistance varies from nothing to tons and from tons to nothing again, it is known that the, grapnel is only engaging rocks or other projections of an uneven bottom. It is frequently necessary to drag over such a ground several times before the cable can be secured.

Having secured one end of a parted cable, the vessel moors it to a buoy and proceeds to search for the other end. When both ends are brought together on deck the electrician holds communication with the shore on both sides to make sure that there are no other defective places and that the cable is perfect in both directions. This having been satisfactorily determined, all that remains is to splice the ends together and drop the cable once more back into thf the sea.