NOTES ON SCIENCE MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XXIX, Issue 8830, 19 March 1892, Page 4 (Supplement)

NOTES ON SCIENCE MECHANICAL INVENTIONS, ETC.

A GREAT IMPROVEMENT IN CDOTING LUMBER. A new and valuable lumber-cutting machine was recently subjected to a most successful trial at Greenpoint, Long Island, in the presence of several of the most prominent lumbermen of New York. The experiment was highly successful, both in the superior character of the work turned out and in tho speed and economy with which it was done. It was pronounced far ahead of any sawing device ever employed for such purpose. It will cut lumber of any thickness, from one thirty-second of an inch to two inches in thickness. It will take a log eight feet long and cut boards at the rate of 40 a minute of any given thickness. There is not the slightest waste of material in the cutting. It is calculated that when saws are used one-fourth of the wood is wasted in sawdust and planing if inch boards are being cut. In sawing boards one-sixteenth of an inch in thickness, the loss is 215 per cent of the material. The machine is 42 feet long, 15 feet wide, and 8 feet high. The object of the machine is to economise time, cost, and raw material. The output of a single machine, when in good running order, is set down at from SO to 100,000 superficial feet per day. It is claimed that this new invention will revolutionise tho making of boards for cigar boxes, backs of pictures, butter boxes, and tho like. At the time of tho test ash, cherry, birch, and basswood logs were cut. The boards dropped from tho blade as if rubbed with sandpaper. One of the witnesses of the trial, Mr. Albert Lewis, of the Wilksbarre Lumber Co., ono of the largest lumber concerns in Pennsylvania, said it was the most perfect thing he ever saw. With our- saws, he continued, wo cannot cut dry lumber at all, while this machine cuts anything. Neither could our saws cut a board one thirty-second of an inch in thickness, as this will. But the best thing it will accomplish will bo tho tremendous saving in the wood itself.

TIIK TELEPHONE PATENTS. Much has been said of late, and much confusion manifested, in regard to the expiration of telephone patents, and the benefit which the public will derive from their expiration. A full and, no doubt, correct statement of all the facts have been put forth as follows:—The fundamental telephone patent will expire in 1893, when the single method of transmission by magneto currents will be open to the public, The practice of extending the term of patents is one which has fallen into desuetude, and nothing is more improbable than that it would be revived in a case like tho telephone. . The inventor of the telephone has been enriched for his gift to the public, and deservedly so. With this tact established, the chances of extension fall. If must be remembered, however, that the telephone industry of to-day has only attained its present degree of perfection by the coalition of many improvements upon Bell's basic idea. There are hundreds of patented inventions which have been acquired by purchase,which will ensure the 801 l Telephone Company quite a firm grip on the business for many years after the fundamental patents expire. First in importance are the microphone patents and the induction coil for raising the tension of feeble microphone currents ; and, secondarily, numerous switches, switchboards, and systems which enable the present company to give good service. A competing company can only offer the public magneto transmission minus these improvements, which, of course, will give only inferior results.

THE DUl'lil.K IiKLT QUESTION. It may seem r-trange, nays a contemporary, that a double belt should be lrucli more effective and durable than a single one, the surface contact being the same in both cases. One cause of superiority is that in a double belt a weak spot is likely to be covered by a stronger part of Ihe other belt, and thus prevent the weak spot from stretching and forming a curve. The main cause of excellence is that in a double belt the limit of elasticity is not so easily reached. When the elasticity has gone from a belt its life is ended. When at work a belt stretches out in length, producing a slack side, which is best shown in a horizontal position, as from the lino shaft to the counter shaft, and when the load is thrown off the belt recovers itself unless the limit of elasticity has been reached. Elasticity consists not alone in stretching out. There must be a tendency to pull back.

CURIOUS knives. When Sheffield first became famous for its cutlery, a peculiar-shaped knife, designed for a variety of uses, was made with great care and sent to the agent of the Cutler's Co. in London. On one of the blades was engraved tho following challenge : — London, fur thy life, Show me such another knife. The London cutlers, to show that they were equal to their Sheffield brothers, made a knife, with a single well-tempered blade, the blade having a cavity containing a rye straw 2£ inches in length, wholly surrounded by the steel ; yet, notwithstanding the fact that the blade was well tempered, the straw was not burned, singed, or charred in the least. It is needless to add that the Sheffield cutlers acknowledged themselves outdone in ingenuity.

AN UNEXPLAINED PHENOMENON

At a recent meeting of the Iron and Steel Trust in England a member showed that the interior of a piece of mild steel may be raised to the fusing point while the outside remains solid, just as if one were to try to melt an iron tube, closed up at each end and filled with some metal of a lower melting point than iron, in which case the heat would penetrate , through the iron and liquefy the interior long before the tube itself would be affected. The member showed some curious specimens of shells of crop ends and other pieces of scrap steel, which had retained their exterior form, although about two-thirds of the original mass had melted out. No explanation of the phenomenon was offered.

WILL IKON' RUST CAUSE FIRE? When oxide of iron is placed in contact with timber excluded from the atmosphere, and aided by a slightly increased temperature, the oxide will part from its oxygen, and is converted into very finely divided particles of metallic iron having such an affinity for oxygen that, when afterward exposed to the action of the atmosphere from any cause, oxygon is so rapidly absorbed that these particles become suddenly red hot, and if in sufficient quantity will produce a temperature far beyond the ignition point of dry timber. Wherever iron pipes are employed for the circulation of any neated medium, whether hot water, hot air, or steam, and the pipes are allowed to become rusty, in close contact with timber, it is only necessary to suppose that under these circumstances the particles of metallic iron become exposed to the action of the atmosphere—and this may occur from the mere expansion or contraction of the pipes—in order to account for many of the fires which periodically take place at the commencement of the winter season.

LUBRICATING MACHINERY. No oil has been made, says a contemporary, that can economically lubricate all the journals of a mill. An oil running a heavy Corliss engine would not do to run a spindle or a fast-revolving dynamo. The former runs slowly and has great pressure and strain on its journals, and consequently requires an oil which will not spread too quickly, but with low gravity and high viscosity. The latter needs a pure mineral oil, viscous and quick, to enable it to enter into tho closest parts of tho bearing as rapidly as the speed at which it revolves necessitates,

MISCELLANEOUS. It is said that a Swiss savant: lias made a discovery by which he reduces milk to a dry powder in such a manner that by the addition of water it at once assumes all its natural properties. For reasons of economy in cost, swiftness of construction, and saving of space in buildings requiring tall chimneys, the material of construction now used is steel, with firebrick and tile lining. An English engineer has recently patented a new form of boiler flue for Cornish, Lancashire, and other large flue boilers, the ■essential feature of the idea being the wavelike serpentine shape. Sheet brass may be cut chemically with good success by the following method :— Make a strong solution of bichloride of mercury in alcohol. With a quill pen draw a line across tho brass where it is to be cut. Let it dry on, and, with the same pen, draw over this line with nitric acid. The brass may then be broken across liko glass cub with a diamond.