Scientific and Useful.

Western Star, Issue 1540, 28 February 1891, Page 2 (Supplement)

Scientific and Useful.

GUN-BARBELS, Inlaying in gold and silver on gun-barrels is done by etching the design with acid and undercutting the edges with a graver, then hammering the soft gold or silver into the design and dressing the surface with the We and polisher. THE WAtEE CIECIiE. Every year a layer of the entire sea, 14ft. thick, is taken up into the clouds. The winds bear their burden into the land, and the water comes down in rain upon the fields, to flaw hack through rivers. Water power is, therefore, fire, heat, or sun power, for if there were no evaporation, there would be no rain, and no streams or rivers. HAS PUBiS WATEE ANY COLOUR ? Dr. M'Pherson states that it has now been undeniably proved that distilled water has a blue colour. A Scotch gentleman of much perseverance has carried out a scries of experiments, and proved this fact, which ho says, is easily demonstrated as follows Let down into water a metal tube (open at the top and closed with a clear glass plate at the bottom) close to a white object 20ft. below the surface. This object, when looked at through the tube, has a most beautiful blue colour. The object would have appeared to be yellow if its colour waa due to light reflected by extremely small particles of matter suspended in the water. FORMATION OF GI/ACIEE3. In high valleys, among the mountains whose tops are covered with perpetual snow, are often found seas of ice, called “ glaciers. They are formed thus Snow that falls upon lofty mountains melts very little even in summer. So in valleys high up among the mountains it gathers to a great depth, and, from the weight of the snow lying above, the lower layers become icy, as a snowball does when squeezed. The upper crust melts a little during the beat of the day, and the water sinks down through the snow, and then freezes at night. From this melting and freezing the mass of enow.ia soon changed into a sea of ico. THE PLIGHT PROBLEM. In a letter to a New York paper, Mr. Hiram Maxim, of automatic gun fame, states that he is studying the problem of the flying machine. He has made numerous experiments with a view to discover the supporting power of a plane driven through the eir at a slight angle with the horizontal, and has devised special apparatus for this purpose. He has also experimented with motors, and stairs that ho has succeeded in obtaining one horso-pjwer from a motor weighing 6ib., and with this expenditure of energy 1331 b. may be supported. It is, he slates, necessary to drive the plane at a speed of at le ist 30 miles an hour, and one of 50 miles is still belter. POE IMITATION OP MABBLB. Good Portland cement and colours that take on that material are mixed dry and made into a paste with the least quantity of water added. One pa‘te has to be made for each colour. The different pastes are placed on the top of one another in layers of different thickness; the mass is pressed from all sides and beaten so that the colours of the different parts impress themselves on each other without uniformity. The result is that more or less deep veins penetrate the mass; this is then sawed into plates, which are pressed in a mould for 12 days, during which time it is necessary to keep them moist as long as they are not en'irely hardened. The plates are polished in the same way as marble. THE LIGHT OP THE FUTURE. Recently, before the New York Electric Club, Prof. E. L. Nichols, of Cornell, lectured on the artificial light of the future, and, after pointing out the results of tests for efficiency with arc and incandescent lights, gas flames, and other illuminants, he stated what must be considered their limited efficiencies. Referring to soma other and little known sources of artificial light, to which ho and his colleagues in Cornell University have recently given considerable attention, he said the most important he considered to be magnesium, and be mentioned some promising results as to its efficiency which be has recently obtained. In the discussion, Mr. Tesla called attention to experiments which be had made by the mixture of a solution of chloride of magnesia with finely powdered carbon. The resulting paste was pressed into a penci suitable for an arc light, and gave good results when burned. He had also experimented with incandescent carbon filament?, in tha stiucture of which the same material had been intimately incorporated. PAHTHBE CHASING ITS PEEY, Mr J. M. Coode records in the new number of the “Journal of the Bombay Natural History Society,’’ the following instance of an exceptional method of hunting which the panther is ocoasiodally forced to apopt. Mr. Coode was lately asked by the Patel of a village in the Amraoti district to accompany him one evening to a forest nursery of young bamboo shoots, to assist in killing a large boar which nightly visited the place and did immense damage. They waited for some time, when, just as it was getting dark, they heard the short guttural sound of a panther and heavy footfall of some running animal. The noises came nearer and nearer until a nilghai and panther could be distinctly seen against the sky-line, the former being chased by the latter. The nilghai kept meaning, and was evidently in an abject state of fear. The two ran round in a circle of about 160 yards diameter, within 30 yards of where the observers were standing, and pissed them twice, both animals making their respective noises. They then disappeared, but Mr. Coode has reason to believe the nilghai got away.—Nature. ‘ YEW. A correspondent of the English Mechanic says: —I am surprised to read so many disparaging remarks on this really valuable wood. It made England the most formidable nation in war for many centuries, until the discovery of gunpowder as a projectile force. Crcssy and Agincourt were won by British yew in the strong arms of our native archers. This slo »- growing tree was grown and protected by Royal decree. Some venerable specimens still exist, though few and far between, in this age of steel. Nottinghamshire was always celebrated for its yew trees. There r was an old saying in the new Eorest, Hampshire, that “ a post of yew will outlive a post of iron.” Bome of those in Norbury Park ; ara recorded in Domesday Book. Some giante still exist in the Lake District. When I was a boy many of our churchyards contained good specimens. There were two ’ reasons for planting them in those melancholy enclosures —first, to insure the safety of the I trees; secondly, to guard them from cattle, > the leaves proving fatal if eaten. I burn all the clippings of my yew hedee as a matter of precaution. I like the wood for turning. The choice pieces are good for cabinet work, ) also for chair-making and walking-sticks, s being very springy and,nice coloured. Tooli handles, too, I have made—very neat things, i Amateur archers like a good yew bow, and a “ lady’s carriagewhip ” might do.