The Arkansaw traveler., 1888-10-27
ConpiLed Ior The AykansGsg TrGUeEev. SCIENTIFIC MISCELLANY.

Dry rot in timber is said to be con- tagious, saws and other tools carrying 1t from the infected wood to sound timber.
 About 15O species of fish are known in the waters of Indiana, according to Prof's. Jordan and Evermann, and about 50 may be regarded as food fishes.
 An English scientific man has pre- served record of family of many toed cats down to the tenth genera tion. Some members have as many as seven toes on each foot.
 A hospital for animals is one of London's new humane institutions, aad the number of horses, dogs, cats and other animals presented for med ical and surgical treatment has already necessitated extension of space.
 Prof. Ayrton defines inertia, from the European standpoint, as "resist- ance to motion," and, from the Amer ican standpoint, as "resistance to standing still" The difference is ex- emplified in the fact that there are hardly 100 electric motors at work in Great Britain, while in America there are 6,000.
 THE GREATEST LIGHT.-Since last May the most powerful artificial light in existence has been that of the St. Catherine's Point light-house, in the Isle of Wight. It is an electric arc, produced between cartoons 24 inches in diameter, and it is estimated to be equal in Illuminating power to rather more than 100000 candles. It is made to revolve, and every half -min- ute mighty flash of five seconds du- ration sweeps around the sea, and is visible at distances that seem incredi- ble.
 AN ANTIsEPTIC PAINT.-The use of wood creosote, which is extensively distilled in North Carolina from the wood of Pinus palalst1Is, is recom- mended by Captain w. H. Bixby for antiseptic purposes. Itdestroys vege- table and animal life, repels moisture, and coagulates fermentable matter. AS paint for wooden or metallic sur- faces, it preserves them from wet and dry rot, rust and the attacks of insects and when forced by hydraulic pressure into the pores of wood it's antiseptic effects are extended to the very centre of the block.
 A MECHANICAL NovELTY.-Ther re- markable Mannesmann process of mak- ing seamless tubes is described by MT. F. Siemens as consisting of passing the bar of solid metal or glass between re- volving conoidal rolls. These rolls are so arranged that the varying ve- locities of revolution with which the different parts of the red-hot bar are brought into contact cause the forma- tion of hollow through the bars centre. Tubes foot i,4 diameter, with shell only quarter of an inch thick may be produced in this way, and great strength is claimed for them. A bar of metal has been introduced between the rolls in such manner as to form a tube with sealed ends, the hollow centre being vacuum.
 ELECTRICITY AS LIGHT.-Acting on MaxwelPs theory that light is really an electric disturbance, or vibration, Prof. Oliver J. Lodge has tried to pro- duce light by direct electric action without the intervention of heat. By means of the oscillating discharge of a Leyden jar, giving as much as ,0OO,- 00O,000 complete vibrations per se- cond, he obtained electric waves that were essentially light in every partic- ular except that they were too long to affect retina. To accomplish the latter the waves had to be shortened from length of three yards to the hundred d-thousandth of an inch. When we are able to generate electric waves of the necessary smallness, the present wasteful and clumsy systems of light ing by the help of steam engines and dynamos will be quickly abandoned.
 AIR PRoPELLERs FOR STEAMsHIPs.- The use of rotating sails, or air pro- pellers, has been considered as a means of driving steamships. According to Mir. H. c. Vogt, the sails need not be very large, and the external appear ance of the apparatus he would pro- pose would be little different from that of the screw propeller, but the wings would be broadest near the cir conference, and be made of sheet steel. Rapid rotation creates rarefaction of the air in front of the wings, causing a thrust to be given quite as great as that from the screw. The screw pro- peiier loses by friction, by throwing water in the wrong direction, and by blows; but the air propeller suffers loss only by the first two, while it de- rives a great gain from seventy five per cent. of the winds. The crude ex- periments thus far made have given promising results.