SCIENCE AND ARTS.

Southland Times, Issue 990, 22 July 1868, Page 3

SCIENCE AND ARTS.

Among the scientific and mechanical apparatus exhibited at the soiree of the President of the Koyal Society at Burlington House, was Wier's Pneumatic Telegraph Signals, for use in houses, in mines, on railways, and on board ship. It was the last that was shewn on the evening in question. A circular dial, with movable hand, and indicatory words, is fitted on deck ; a similar dial is placed in the engine-room, or on the gun- deck, or at the rudder, each connected by metallic air-tubes with the one on deck. The captain, or officer of the watch, wishing to give an order, turn 3 a handle fitted in the side of the dial by which he stands, and instantaneously the same signal appears on the steersman's dial, and he obeys the order. To the captain it is very important that he should know whether, in accordance with his order, the ship is obeying the helm, and this knowledge he obtains from a small tell-tale hand placed on his dial, which moves exactly as the rudder moves. The advantage of such signals as these over the old method of shouting orders through a trumpet is obvious. In the same way, the captain may send his commands to the captains of the guns, or to the engine-room ; and should any of the tubes be shot away they may be immediately replaced by flexible tubes of vulcanised india rubber. Moreover, the captain might place himBelf at the masthead during an engagement, above the smoke, where he could best see what was going on, and send down his orders by signal from that elevation ; besides which, by a modified form of the signal apparatus, small enough to carry under his arm, he could actually fire any gun in the ship from his station at the mast-head. He presses a

i j key in the top of a small box, the iinpuls' V j pas-^s riirouirW the slonder aiv-tube, act vj | upon fc!i.: cock, and fires the gun. W< - li. :.(,=■ tiiac tiie Bellerophon aad somi b other ships of the royal navy are to bi 1 fitted with Mr "Weir's signals. Ani s one who read this description will se< 1 that they could be used in dwelling - houses. The impulse can be sent througl { a thin tube 250 feet in length. Imagine 3 the convenience of being able to talk tc , any part of a house, and of giving orders [ without first requiring some one to comt „ up-stairs to ask what; you want. i The total eclipse of the sun which is , to take place on the 18th of August next , is already exciting unusual interest i among astronomers, in consequence of 3 the (comparatively) long period of dark--1 ness which it will occasion. A line drawn b on the map from Aden across Hindustan 3 and away to the southern coast of New Guinea, will represent pretty accurately , the line of total obscuriby. It so happens, • that on the day above named the moon will be almost at its nearest to the earth, and the sun at its furthest from the ; earth, consequently the moon will hide the sun so completely that the ; duration of the total darkness will . be nearly seven minutes. This s is so rare a phenomenon, that all in- ; terested in cosmical science are earnestly desirous of getting all they can out of it by observation. Foremost among them, the Royal Society have taken such . measures that, if the weather be only , favorable at the time and place of , observation, most satisfactory results i will be obtained. They have sent out to India a number of newly constructed instruments — telescopes, spectroscopes, prismsjactinometers. and others, by which, all the phenomena of an eclipse may be well observed : and as the observers will be some of the most skilful of the officers employed on the great trigonometrical survey of India, we may hope that the highly important questions involved in the phenomenon will be cleared of their present uncertainty. If the south-west monsoon, which will then be blowing, will only leave the sky clear at the place of observation, we shall by Christmas next know more about the sun and its light and atmosphere than hitherto. — Home Paper.