SCIENCE SIFTINGS.

Auckland Star, Volume XXXVI, Issue 84, 8 April 1905, Page 10

SCIENCE SIFTINGS.

A SHADOW CLOCK. The shadow clock, invented by Professor Hirth, of Munich, seems to be preeminently adapted for the/sick room or hospital. By depressing a button, says "Work," a small electric lamp placed under the dial of a clock face and hands upon the ceiling in a highly magnified state. Viewed from the bed of a reclining invalid, it obviates any irksome craning of the neck. THE FIRST STEAMBHIP. The first attempt to propel vessels by steam is claimed by the Spanish to have been made a.t Barcelona by a paddlewheel vessel, under the direction of Blasco dc Garey, in 1543. Papin, in France, about 17.07; Jonathan Rulle, in England, 1736; William Henry, in Pennsylvania, are also mentioned in connection with it. But a steamer placed on the Delaware, at Philadelphia, by John Fitch, 1787, is the first worthy of being so called. That he clearly foresaw what a complete revolution in the means of ocean transit his invention foreshadowed is vividly evideiiced in a letter he wrote to a friend asking for a loan of £50 to complete this boat. In it he wrote: "This, sir, whether I bring it to perfection or not, will he the niode of crossing the Atlantic, in time, for packets and armed vessels." To two visitors on another occasion, to whom he was pointing out the grand possibilities of his invention, he said: "Well, gentlemen, although I. shall not live to see the time, you will when steamboats will be preferred to all other means of conveyance, especially for passengers." 'Poor fellow," remarked one of his visitors to the other as they left, "what a pity he is so crazy!" SEASONAL DEVELOPMENT OF MARTIAN CANALS. A further contribution of observed phenomena in support of his theory concerning the causes which produce the seasonal development of the canal on Mars, is published by Mr Lowell in the January number of "Popular Astronomy." The particular canal therein discussed is Brontes, which is 2440 miles in length arid connects along a gceat circle, in nearly a north and south di-' rection, the two important points Linus Titanum and the Propontis. From a study of 90 drawiDgs made during the ! period January-July, 1903 y six of which j are reproduced on the plate accompanyI ing the paper, it was seen that the ! visibility of the canal increased after ■ the summer solstice in the northern hemisphere, and, further, on dividing the canal into five nearly equal sections : from north to south, the section nearest ! the north polar cap became strengthened I first, and the others followed in order of their north polar distance. This is I plainly shown on the visibility "carI touches" given by Mr Lowell, who conI sid'ers the phenomena as a further proof Jof his theory that the visibility of a I canal is due to vegetation, quickened J by the water loosened at the melting of j the polar snows and flowing towards ', the equator. The extension south of the I equator is considered as ' a probable proof of intelligent artificial interfer- ! enco in the propulsion of the water.— "Nature." LAKELAND. In the survey of the Scottish lakes, which is now nearly completed, a depth of 1017 ft. has been reached in Loch Morar. This proves to be the deepest lake jin the United Kingdom. Only seven deeper lakes are known- in Europe, four being in Norway, and three in Italy.

THE LATEST CUXARDER. The twin-screw steamer Caronia, the largest vessel launched last year, left the builders' yard at Clydebank in December, and is now ready for the sea. She is the biggest boat of the Cunard fleet, and at the same time the largest vessel ever built on the Clyde or in Britain. One or two ships of larger size have been constructed at Belfast, but the Caronia will have a greater speed than these leviathans, and. certainly, so far as passenger accommodation is concerned, the new Clyde boat will not be surpassed by anything afloat. The Caronia is an eight-decker, 678 ft in lengui, 72ft in breadth, 52ft in moulded depth, and her gross measurement is approximately 20,000 tons —only 4000 less than the White Star liner' Baltic, the largest vessel ever built. Compared with other ships of the Cunard line, the Caronia is nearly 6000 tons larger than the Saxonia and Ivernia, the biggest boats at present in the company's service, and over 7000 tons larger than the famous Fairfield fliers—Campania and Lucania. A sister vessel to the Caronia, which will be known as the Carmania, is nearing completion at Clydebank, but she will be propelled by "turbines, while the Caronia has engines of the ordinary reciprocating type. Although not so long as the Great Eastern, the Caronia is of greater tonnage, greater horse-power, and greater speed than that most remarkable product of nayal architecture. THE SPEED OF STEAMERS. The "Hamburgher Naehrichten" states that a professor of physical science at the Lyceum of Leghorn is at the present moment in Liverpool submitting an invention to representatives of the shipping interests. The invention concerns the increase of speed of steamers, and this ;by an entirely novel method. The professaor believes that there is little prospect of being able to increase- substantially the present driving power of shipsengines. He has therefore concentrated his attention on the problem of lessening the resistance of the water, and it is this problem which the inventor claims to have solved. As the resistance of the water depends upon its density, it is clear that the latter must be decreased. This is done by forcing air through the keel and sides with tremendous force. By so doing it-is claimed that the water in front and around tne ship becomes a light, foamy mass, offering a greatly reduced resistance to a ship in motion. The invention has already bean patented Jn Italy and England. Experiments tried in the harbour of Leghorn are stated to have given an increased speed of 25 per cent.