SCIENCE and INVENTIONS.

New Zealand Herald, Volume LIII, Issue 16372, 28 October 1916, Page 4 (Supplement)

SCIENCE and INVENTIONS.

OIL ENGINES FOR BATTLESHIPS. Ax English naval architect in a recent study of the question of applying oil engines for the propulsion of warships states that .in the case of a battleship he found that with an equal number of shafts, equal power and speed can be obtained with double-acting two-cycle engines as with steam, auxiliaries being included in each case and the machinery being equal. He found that the radius of action could be increased at full speed at least three times and at cruising speeds at least four times. PARACHUTE AND AEROPLANE. According to the Scientific American, the Germans arc said to be discussing the employment of a parachute to salvo a damaged aeroplane with its pilot. The sustaining power of the parachute is astonishing. Expressed mathematically, the speed of descent varies as the square root of the weight of the load. That is, if a certain parachute will carry a load of ten pounds to the earth at a velocity of one ' foot per second, it will fall with a load of half a ton at a velocity of only ten feet per second. It appears, then, that the problem of construction is merely that of building a parachute whose parts will sustain a given strain without displacement or rupture. The solution of this problem is all that is required for the realisation of a parachute that will fall, with iny given load whatever, at a moderate velocity, ELECTRIFIED CROPS. According to the Electrical Review, a I Miss Dudgeon, of Dumfries, Scotland, lias for some years conducted important experiments and observed the effects of electricity upon the growth of potato and oat crops. Most satisfactory results were .-x----perienced with the potato crops in three successive years, the increased yield per acre with electricity being 1204 pounds ;n 1912, 1456 pounds" in 1913, and 2576 pounds in 1914. In oats, tho difference was most conspicuous right from the beginning of the experiment, and the elec-trically-treated crops suffered less than others from the drought which prevailed The difference amounted to 31 per cent, in grain and 31 per cent, in straw in favour of electricity. The Dumfries experiments prove that under the influence of tho electric discharge the ingredients in the soil are more soluble and more easy of assimilation; that by the aid of electric current sap is enabled to flow more vigorously, and the formation of sugar and starch increases also that respiration, ab-. sorption, and evaporation are accelerated. WATER PRESSURE. A cubic foot of sea water weighs 64 pounds. _ Each cubic foot may be regardod as standing on a base of one square foot. Therefore, the pressure at the base of a cubic foot of sea water is 64 pounds oer square foot. Now, a cubic foot of water, having a base of one square foot, must bo one foot high. Tho pressure at its base (64 pounds per square foot) is, therefore, the same as that pressure which would be encountered at one foot below sea level. Now, 144 square inches make one square foot. A vertical column of water having a sectional area of one square inch would, therefore, weigh 1/144 as much as a column equally high, but having a sectional area of one square foot. Since the pressure per square foot is 64 pounds, the pressure per square inch is 1/144 of 64 pounds equal 64/144 equal 4/9 equal 0.44 pounds per square inch. At two feet below sea level, or double the depth, dotiblo the height and weight of water stands on each square inch, therefore, the pressure is double equal 2 multiplied 0.44 equal 0.88 pounds per square inch. Each i extra foot of depth adds an extra pressure of 0.44 pound per square inch. To find the , pressure at any depth multiply the depth , in feet by 0.44 pound per square inch. SOOT PROM CHIMNEYS. The big chimneys of industrial plants : often become partially obstructed by accumulations of soot, which are expensive to ; remove by ordinary methods. A how and economical scheme has been found for doing this work, and that is to shake the soot down by the shock of an explosion. A simple and effective way to do this is to make a small cannon by drilling a role 1-Jin in diameter and lOin deep in a piece ! of 4in shafting about 15in long. This gun may be mounted vertically on a plate .if iron, and. is tired by a fuse hole drilled in one side of the shaft to intersect the bottom of the bore- The gun is charged with blasting powder up to about two inches of the muzzle, and the remaining space is filled with dry clay and tamped. The gun is placed for firing on the flue floor , at the bottom of the stack, and three or four shots will ordinarily shake down the soot, depending on the condition of the stack. A gun of the sizo given, and with the above, charge, is sufficient for a stack 100 feet high, but a longer gun, with a somewhat increased charge, would be necessary for a taller stack. This method of cleaning chimneys is said to have been used for several years with satisfaction, and without injury to the stack. It should be noted that the gun directs the air disturbance upward, while if a loose cartridge were fired it would he likely to blow out the base of the stack. BULLET-PROOF FABRIC. With the object of offering protection to soldiers against bullets and shrapnel splinters, an English concern has developed a fabric which, although of lignt weight, is said to astonish everybody who has had the opportunity of testing its impenetrability. For the present the new fabric is being made into shields of two types; first, the single shield which is worn in front and serves to protect 'he wearer from bullets second, double shield for protecting the chest and back. Willi regard to the latter type, it has been found in the present war that some protection for the soldier's back is quite necessary, because of the high percentage of casualties arising from (lying shrapnel. Obviously it is not possible' to give a detailed account of the impenetrable fabric. The pad of fabric is encased in an outer covering of khaki fabric, the former being a book-like section with several pleats to the inch, chemically treated after it is made up and the whole inserted within the outer jacket and sewed up. Two bullets were tired from a service revolver at eight paces, with a bullet velocity of 750 feet per second, at one of the fabric shields. The lead bullets plainly showed the fabric markings on their mashed noses, demonstrating that the fabric wan the last thing struck by them before they came to a halt in the folds of the shield." " FLOOD-LIGHTING." A bill authorising the New York World to raise, by popular subscription, 30,000 dollars to install apparatus for the flood lighting of the Statue of Liberty in New York harbour, has been introduced before Congress. At the present time the statue is practically invisible at night, and its lighted torch attracts but little attention. For its efficient flood lighting it is estimated that light from concealed projectors to the intensity of from 6ft to 12ft candles will be required. An expenditure of 10,000dols. for the illumination of Niagara Falls has been authorised by the City Council of Niagara Falls, This sum is to be expended in carrying out the floodlighting scheme proposed by a Chicago concern, which promises to be so uniform as to eliminate- dark spots in the centre and wings. It is said that the projectors to be used will bo so powerful that their rays will readily penetrate the densest mist, although "the current consumption will be low. The city of Seal Beach, Cal., is now attraction attention because of the novel idea of illuminating the entire water front which has been carried out by the officials. A battery of 41 powerful searchlights, each being of more than 25,000 candle-power, has been placed on the outward edge of a long pier which extends out into the ocean from a point at the centre of the waterfront. The, illuminated waterfront may be seen far out at sea, while the searchlight beams are visible for miles inland.