NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XXXIV, Issue 10407, 3 April 1897, Page 4 (Supplement)

NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

THE MERIDIAN.

J. D. Varxey, in a paper in the Journal of the Association of Engineering Societies, describes one of the latest devices for determining the meridian from the position of the sun without computation. It consists of the usual transit-theodolite, with one attachment, and one modification. The modification is that the telescope h carried in a tube which is connected to the horizontal axis in the same manner that the telescope usually is, and is free to revolve in this tube about its own axis. The attachment is a mirror revolving on an axis attached to a email ring which fits on the object end of the telescope. Slow motion id provided for. The mirror is set with the aid of the horizontal circle and a special target, so that) it reflects the line of collimatiou at an angle equal to the angle between the earth's axis unci a lino from the earth to the sun (i.e., ninety degress—sun's The telescope is set at an angle to depresson equal to the latitude of the place. The instrument is revolved about its vertical axis, and the telescope about its own axis, until the image of the sun appears in the cross hairs, and then the instrument is pointing in the meridian. The writer claims that with due regard to refraction and hour angle a meridian of sufficient accuracy for all ordinary work can be obtained. • FIGURING THE CAPACITY OF BOILIiRS,

As no method has been devised for testins the evaporative capacity of a boiler without the furnace on which it is placed, all so-called tests partake mure or less of the nature of guesses, as it is impossible to tell with any degree of exactness whether the results obtained, favourable or otherwise, are to be credited to the design of boiler or furnace. To this uncertainty is probably to be ascribed the well-known discrepancy in the size of boilers offered by different makers when any particular capacity is called for, which again has led to the now common practice of laying down specifications of size of shell, number and diameter of tubes,etc., when bids on boilers aro callod for. The boiler maker thus bocomes merely a mechanic, whoso whole duty it is to assemble the materials called for and put them together in'a workmanlike manner, and being thus to a great extent relieved of responsibility, is expected to lower his price proportionately. While this mny be satisfactory to somo who would rather use their muscles than brains, it discounts ability and ao is disliked by those who, from close study and long experience, consider themselves fitted for better things. In a recent case where bids were asked for a number of boilers for a municipal plant, instead of specifying the heating and grate surface to be furnished per horse-power, there was stated the amount of water to be evaporated, the quality of the steam, i.e., its dryness as shown by the calorimeter, and the efficiency to be reached, with the kind of coal it was the intention of the city to use. This new departure would seem to be worthy of an extensive following, as it places the responsibility nf the design of boiler and furnace where they belong without dividing it between designer and builder as the other plan doe.?.—R Kiddell, in the Boiler Makor.

KLECTBICAL WAR DEVICES,

The microphone is now being experimented upon with a view to making ib available for detecting tho approach of a hostile force whilo the hitter is yet some distance away and far beyond ordinary hearing. Tho microphone will magnify the sound of the footsteps of a fly until it is almost as loud hh the noise made by it man's feot. In its proposed modifications it will attune itsolf to the vibrations made by the feot of distant soldiers on tho march and thus" betray their presence and their probable numbers to tho pursued or pursuing army possessing such a valuablo instrument. A great chango has taken place in the sapping and mining department! of the army since electricity was introduced on a practical basis. Mines are now laid by the engineer corps and exploded with a far greater degree of nicety than when slowburning fuses were used. Rivers can now bo guarded almost by one man, stationed where he can operate a circuit in which a number of submarine torpedoes aro included, The torpedoes used in the army differ from thoso used in the navy. The latter include u propelling apparatus which carries them through the water; thoso used in the array are generally anchored at the bottom of a stream. Given a number of torpedoes, judicially placed, a single officer could make tho passage across a river by an army a decidedly hazardous undertaking. The value of electric firing as far a» the guns themselves are concerned is admitted, particularly on shipboard or for coast defence. There is no losb interval of time between tho command of tho gun captain and the actual exploding of the piece. The instant tho gun \i to be fired the officer connects the circuit and the ball is on its way to its destination, If the object aimod at be a distant vessel, rising and falling with the waves, or a moving body of cavalry on land, the value of an instant discharge can be easily recognised.

TETANUS ANTITOXIN.

Consul-General Frank H. Mason, writing from Frankfort-on-the-Maine, says that from tho evidence presontod it would appear that tetanus, if not already conquered, is in a fair way to be successfully overcome. In tho Deutsche Modicinischo Wachenschrift (Berlin) for October 23 appears a joint announcement by Prof. Dr. von Behring, of diphtheria-antitoxin fame, and Prof. Knorr, of Marburg, describing the , qualities and best methods of using the new tetanus antitoxin, which is now prepared under Government supervision as a commercial produce by the Farbwerke at HoechsbonMaine, And offered for use by medical practitioners under the same conditions as diphtheria-antitoxin from the same source. Tetanus, as is well known, is an exceedingly painful and hitherto usually fatal disease caused by blood-poisoning, generally the result of a wound. It is believed by physicians to be caused by tho introduction into tho 'system of a minuto organism which rises from the ground in certain localities, so that the prevalence of tetanus varies greatly even in dilForont districts of tho same country. At all events, tho disease has its characteristic microbe, which has been recognised, isolated, described and reproduced by artificial culture. The distinctive symptom of tetanus is a persistent spasm of the voluntary muscles, aggravated by light, noise, or other disturbing influence to which tho patient may be subjected. These spasms may affect any muscular portion of the body, but when, as is often the case, the maxillary muscles are principally attacked, the resulting malady is known as lock-jaw. The tetanus antitoxin described by Profs, von Behring and Knorr isjsimilar in nature, action,and in the methods of its preparation to the antitoxin of diphtheria. A MOTOR FOB SEWISG-MACHJNKS. A patent has been granted in the United States to Mr. F. A. Burrows, of Columbia, S. Carolina, for a "motor" for sewingmachines and athor light apparatus in which the motor is wound up by the weight of the operator in sitting down. When the motor ceases to run the operator starts it again by simply rising from his seat and then sitting down. On a casing is a loose drive shaft on which is a loose* gear wheel, a helical spring having one end fixed to the drive shaft and the otiicr to the gear wheel, while a loose disc on the drive shaft has a flexible connection with a lever carried by the casing, the loose disc having a pawl engaging a ratchet disc. A NOViiL METHOD OF PRESERVING OYSTERS. The aim of this invention is to compel the bivalves to which ib is applied to retain their natural jaices, so that, when required for use, they may be found in a fresh state. For this purpose the shells are rigidly fantened together by small plugs of wood, which aro driven through the outer edges at the opposite side to the hinge of the shell. The wooden plug is driven through perforations mads for it? reception, and as it quickly swells with the moisture, it is firmly held in position, and tho oyster is hermetically sealed, until tho edge of the shell is broken previous to the insertion of the fishmonger's knife.

A NOVEL INVENTION.

L'Electricion, Paris, quotes from the Optician, London, an account of an invention by a man named Wilcox, in which a minute incandescont electric lamp is fastened to a pen near its point in order to illuminate the writing. " A little reflector," it layi, " placed behind it, prevents the light from dazzling the eye*, and directs it toward the paper. This arrangement . . . may be applied also to a pencil or to any instrument of the ume tort."