SCIENCE AND ART.

New Zealand Herald, Volume XIX, Issue 6296, 21 January 1882, Page 3

SCIENCE AND ART.

VENTILATION of bedrooms. The Lancet had some comments on this tropic which may, be read with as much profit in New Zealand aB in London. It says : If a man were deliberately to shut himself for some six or eight hoars daily in a stuffy room, with closed doors and windows (the doors not being opened even to change the air during the period of incarceration), and were then to complain of headache and debility, he would he justly told that his own want of intelligent foresight was the cause of his suffering. Nevertheless, this is what the great mass of people do every night of their lives with no thought of their imprudence. There are few bedrooms in which it is perfectly safe to pass the night without something more than ordinary precautions to secure an inflow of fresh air. Every sleeping apartment should, of course, have a fireplace with an open chimney ; in cold weather it is well if the grate contains a small fire, at least enough to creatc an upset current and carry off the vitiated air of the room. In all such cases, however, when a fire is used, it is necessary to see that the air drawn into the room comes from the outside of the house. By an easy mistake it is possible to place the occupant of a bedroom with a fire in a close house in a direct current of foul air, drawn from all parts of the establishment. Summer and winter, witli or without the use of fires, it is well to have a free ingress for pure air. This should be the ventilator's first concern. Foul air will fiui an exit if pure air is admitted in sufficient quantity, but it is not certain pure air will be drawn in if the impure air is drawn away. So far as sleeping-rooms are concerned, it is wise to let in air from without. The aim must be to accomplish the object without causing a great fall of temperature or a draught. The windows may be drawn down an inch or two at tlio top with advantage and a fold of muslin will form a " ventilator" to tako off the feeling of draught. This, with an open fircplace, will generally suffice, and produce no unpreasant consequences even when the weather is cold. It is, however, essential that the air outside should be pure. Little is likely to be gained by letting in fog or eveu a town mist. ALARM-BUOY FOR BRITISH WARVESSELS. An important fitting has been recently supplied to English war-ships, in the shape of an alarm-buoy, the invention of Captain Cator, which will enable the ships of a squadron to keep line and distance in a fog and thus prevent the chance of a collision. The buoys, which have been constructed by Messrs. Tipping & Co., of Portsmouth, are built in three water-tight compartments, and consist of a horizontal iron tube with conical ends. The after-end is fitted with a screw propeller, which revolves as the buoy ia drawn by the ship through the water, after the manner of a patent log. At the top is a gong, the clapper of which is connected by suitable gearing with the propeller, and which is made to strike the gong at every revolution. Dragged at the stern of the leading ship, the following vessel will be able to follow its leader on the darkest night, while the number of beats of the gong in a minute will enable the squadron to maintain a uniform speed. The necessary stability is given to the buoy by a deep iron keel, while wooden balks bolted to the side reduce the tendency to roll and keep the buoy at its proper waterlevel.

CAUSE OP EARTHQUAKES. Dr. K. von Fritsch of Halle says that the cause of earthquakes <locs not exist further down from the surface of the earth than 10 or 14 miles. After citing a number of instances to show how far the shock of a steam hammer or that produced by an explosive may be felt, ho appears convinced that rather feeble forces produce earthquakes which make themselves very sensibly apparent at great distances from the active centre. He says that earthquakes might bo and must be produced by the increase and decrease of volume oF rocks under the influence of physical and uhcmical torces, and by concussion, by the opening of crcviccs in rocks, and by the subsidence of masses of rock due to these agencies. Many schists arc subjected to extension stress, and when crevices occur the schists must enter into oscillations like those produced in tuningplates. A NEW WATER. ELEVATOR. Rotary machines have been employed for raisingrwater during many years, but hitherto they generally consisted of an immovable cylinder, in which the water is circulated by rotating paddles until it acquires sufficient centrifugal force to elevate it through a pipe. The highest lift attained in this way has been 130 feet, but a recent invention by a young French engineer, M. de Romilly, enables water to be raised 500 feet or more. The new elevator consists of a flat horizontal cylinder or pan, fed with the water to be lifted, and rapidly rotated round a vertical axis by means of a pulley. The motion of the pan causes the water to circulate round its internal walls, and a tube reaching down from the height to which the water is to be raised is brought into the pan, and terminated in a curved nozzle turned towards the circulating liquid. The swirliug water, by virtue of its momentum, rushes into the nozzle and~ascends the tube.

At the York meeting of the' British Association Mr. W. Galloway, an expert on the subject, said he had convinced himself by experiment of the inflammability of coal dust, and that if water was sprinkled on the floor of dry mines before blasting the worst of explosions would be prevented. A ready method for hot fomentations is to place flannels in the steamer of an ordinary potato steam kettle. They readily become permanated with the steam when the kettle is placed on the fire, and can be readily changed without any fear of scalded fingers duriug the .attempt to wring them sufficiently dry, as in the ordinary method. At the meeting of the Darlaston Sanitary authority lately it was reported that five persons had been attacked with blood poisoning, one of whom had succumbed, in consequence of drinking water highly contaminated with sewage matter. It was stated that water taken from_ certain wells had caused 13 deaths from scarlet fever in four weeks. It, was decided to close the wells and obtain wholesome water for the people. A curious fact, and one showing the value and peroision of modern engineering, may be mentioned in connection with the recent picking up of one of tho Atlantic cables, which became useless some ten years ago, and which has since been lying neglected on the bottom of tho Atlantic at a depth of some 2000 fathoms. The location of the fault, with so much exactness, and the small expense of picking up and repairing the cables at a slight comparative cost, gives additional value to ocean telegraph property, and increased confidence in that scientific engineering which is able to calculate so closely into such hidden mysteries. Dr. Gatling, of Hartford, the inventor of the Gatling gun, has produced a gun that is said to be the best one yet. It will be mounted on the gunwale of a ship, with apparatus for sweeping three-fourths of the horizon, and the range is three miles at least. It has a rifled steel barrel inches long, witli a calibre of 145 inches, and throws a shot weighing 1} pounds, and steel-pointed, capable of piercing the iron of a torpedo boat three miles away. It is a breech-loader, and is fed by hand, but the loading and firing ia automatic. Two men can manage it. It is called the Gatling torpedo gun. Some observations on meteors, conducted this year between July 25th and July 30th, were recorded in a paper by Mr. Cruis, which was read before tho French Academy on September sth. As the horary average increased rapidly between the evening and the morning hours, and as a remarkable recrudescence occurred immcdiaiely before sunrise, the presumption was that the stream of meteors moved in a direction opposite to that of the earth. This conclusion received further support from tho fnct that the meteors seen af:cr 5 a.m. moved with great velocity, and were very brilliant. Their direction was probably very little inclined to the plane of the ecliptic. Experiments in electric lighting have been made by means of Mr. Faure's system of accumulating batteries, which s'ore and retain tho electric energy and redistribute it when required. Last year, it wilt bo remembered, a. box of stored electricity was sent from Paris to Sir William Thompson in Glasgow, and tho matter was discussed by scientists throughout the world, andthe conclusion arrived at was that stored electricity was nothing more than a scientific curiosity that could not be practically applied. Messrs. Faure and Thompson, however, demonstrated recently at the Westminster A quarium that it is perfectly practicable to light a house, and still more easily a whole district, by stored electricity. That which was employed in lighting the tanks of the aquarium had been generated in Woolwich and carted down to Westminster, where it arrived an hour before wanted.