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great strain. If, however, it were made a sharp curve at, say, one hundred miles in one solid piece of metal this objection an hour, lean to the inside? Rather should not prove insurmountable. A would not the centrifugal force overcome failure of the gyroscope to operate while that of the gyroscope and send the train the train was at a standstill would of from the track? Meanwhile, in spite of course mean the loss of stability and in- objections that may be offered, Mr. Brenevitable disaster. That is why Mr. Bren- nan is going confidently ahead with his nan purposes to place the gyroscope in a plans for constructing a large-sized partial vacuum, so that even after the mono-rail coach, and demonstration of its power is shut off the wheel will revolve usefulness or its failure will not be long for a considerable time. Finally, the postponed. Science and industry are question arises: will the car on making deeply interested in the outcome.

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Piping Mine Débris

By Dennis H. Stovall

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NE of the embarrassing placer mines that are confronted with problems that have been the “dump problem.” This elevator successfully solved by the is easily constructed by any mine foreingenious Western miner, man or superintendent. Primarily it

is that of taking care of consists of a section or more of standard

w the mountains of débris, hydraulic steel piping, set at an incline boulders and gravel that are washed of sixty or seventy degrees, over the end down in the course of surface digging of the bedrock race of the diggings. At in the quest for gold. After a half-cen- the base of the pipe a inonitor is set, with tury of constant work, the diggings of many of the placer mines have narrowed down, and now confine themselves to the more remote slope's and gulches, which, a few years ago could not have been worked by the methods then known. In former days every hydraulic placer mine had to have good "dumping grounds ;" which meant that there must be a sheer fall or drop of from twenty-five to two hundred feet from the end of the sluices. Unless there was such fall, the sluices would soon be choked up by the accumulation of boulders and debris. But now diggings are being profitably worked that have practically no natural dump, an artificial dumping ground being created through the assistance of the hydraulic elevator.

The tubular type of tailings elevator is now being used and introduced on all Western TUBULAR ELEVATOR IN OPERATION ON A WESTERN PLACER Mixe,

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the nozzle directed to throw the stream capacity to meet all requirements for up the pipe. The discharge from the eight or ten years. planted monitor nozzle causes a suction, The force and power of an elevator of and this draws the entire flow of water this type are remarkable. Boulders from the race, together with all boulders, weighing 500 and 600 pounds are caught tailings and débris, up the pipe, hurling up by the monitor and hurled up the the whole mass into a sluice built on the elevator as easily as a boy would toss upper level, and supported by trestle. up a marble. Anything that will go This upper sluice is provided with riffles, through the pipe is elevated, and as nothand catches the greater part of the fine ing larger than will pass through the gold. The lower sluice, or bedrock race, pipe is allowed to roll or flow down the the flow of which is drawn up through race, choking seldom occurs. the pipe, is also provided with riffles, and What diameter of pipe to employ decatches nearly all the nuggets and coarse pends of course upon the size of the

monitor and the amount or strength of The height of the elevator depends its gravity head, as well as upon the genupon the force of the giant. If the moni- eral water supply. A fifteen-inch pipe tor has a gravity head of only 200 or 250 will elevate higher than a twenty-inch feet, it will elevate but twenty-five feet; pipe, for the same reason that a threebut if it has a head of 400 or 500 feet, inch nozzle will throw a stream a greater it will elevate thirty or forty feet. Some distance than a four-inch nozzle when elevators of this type are arranged with a subjected to the same pressure. For all second giant set midway of the inclined general purposes the twenty-inch pipe is pipe, reinforcing the force of the one at best, and is the size most generally used, the base, and the two easily elevate all as it is large enough to take care of the tailings and by-water to a height of forty- entire flow of the bedrock race, and will five or fifty feet. This elevation sets the not choke as easily as pipes of smaller upper sluice high above the bedrock, and diameter, which experience shows are too affords dumping grounds of sufficient prone to clog up, thus delaying the work.

gold.

Steel Hardening Minerals

By John W. Hall

MOR some time past the and recently the Bethlehem, Pennsylva

United States Geological nia, manufacturers have been making cey Survey has been making ob- many experiments along the same lines.

servations as to what is be- The principal minerals used by the Enging done with a new group lish company and by the Bethlehem peo

of steel hardening minerals. ple in their experiments are manganese, While these minerals have been known tungsten, vanadium and uranium, and to the foremost metallurgists for some others of the rare minerals. The effect years, and while the minerals themselves of these minerals in steel manufacture are not new by any means, yet their ap- is that one or two per cent of them will plication to steel manufacture is of very entirely change the nature of the metal, recent date and heretofore they have oc- and it is to see how these qualities can be cupied more the position of curiosities utilized most effectively that experiments than of commercial importance.

are being made and observed by officials An English firm has been using steel of the Geological Survey. hardening alloys for a good many years, The attention of the Geological Survey

has been especially directed to operations though it is very hard to work up, will in Texas, Utah and California, and it hold an edge after it gets a dull red heat. has been observed that where a few years This enables lathes where tools of such ago the practical prospector seldom knew steel are used to be speeded up so that what a tungsten mineral was, now the their output is increased about three-fold. exception is to find one who does not The practical machinist will appreciate know. Improved methods of mining are what it means to work with a tool you being utilized and new and rich deposits cannot "burn” in the machine. A disadare being uncovered.

vantage of these excessively hard steels Up to one year ago the world's output is that it is hard for the blacksmith to of vanadium was only about two hundred forge them. They are very refractory pounds per month and the process by even at the highest forge heat, and there which that was extracted from other is hardly any way of sharpening them minerals was very expensive, which re- but by grinding. No doubt this objection sulted in giving to it a value many times will be overcome at an early date. the value of gold. Even considering the The practical usefulness of manganese fabulous cost, its effects on steel produced steel has already been demonstrated in profitable results; but, as seen, the total dredger construction, where bearings output was sufficient for working only a and working parts made of it will stand few tons of steel. Vanadium is now be three times as long under the cutting ing used extensively in the manufacture action of sand and gravel as ordinary of the higher grades of automobiles, be- steel. ing utilized in conjunction with chromi- The mining regions of Texas are laden um for such work as axles, crank-shafts, with rare earths, as shown from the driving-shafts, gears, connecting rods Geological Survey's observations. In and springs. In spring-steels a large per- Llano county the Westinghouse company centage of manganese is also used. It is is mining yytrium and thorium for use in contended that steel made with these the construction of the Nerst lamps. alloys furnishes greater resistance to They employ more than one thousand shocks, whether from sudden or minute men in getting out those earths. Yytrium vibrations, than any other metal, and im- and thorium are good electrical conparts to steel dynamic properties not ob- ductors when hot, but non-conductors tainable by any other method of metal- when cold. These earths, formed in lurgy.

pencil shape, take the place of the filaBy reason of recent developments in ment in the old style of lamp. America, and the opening up of large In the same region of Texas there were fields near Lima, Peru, vanadium has observed immense dikes with masses of been put on a commercial basis, the price pure feldspar thirty feet in diameter and has sought its proper level, and it is now running theoretically about seventeen worth about half the price of silver. per cent in potash. While this deposit

Regarding the practical application of has never been worked commercially, it the steel hardening minerals to the iron is more than probable that an early date and steel industry, it has been demon- it will be utilized in the manufacture of strated that a small per cent, say of potash fertilizer. Thus the world's suptungsten, will make a tool-steel that, al- ply of useful metals is ever increasing.

Seeing Beyond the Microscope

By Dr. Alfred Gradenwitz

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Y the application of the it was thought that no limits would be Ny electrical

electric arc to the micro- encountered in extending the scope of scope, two European scien- this valuable instrument, and that the tists have now opened the realm, not only of the most minute organway for an intimate knowl- isms, but even of molecular and atomic

edge of the life and struc- structures, would be open to investigature of bacteria, and improved methods tion, provided the magnification were inof dealing with them will result.

creased sufficiently. After the invention of the microscope, Now recent researches by Helmholtz

and Abbe have shown that an insight into the structure of minute objects can be obtained by means of the microscope, only if the diameter of the former is upwards of one-four millionth of a millimeter. This limit is due to the phenomenon of deflection occurring with objects of smaller size, which prevents the production of any optical image ; that is, objects of smaller size do not reflect a sufficient number of light rays to the eye to create an impression, especially after these have been made less intense by passing through the lenses of a microscope. Now the dimensions of certain bacteria are unfortunately as small as or smaller than this minimum diameter. H. Siedentopf and R. Zsigmondy, therefore, made a most valuable contribution to the advance of optics, when they designed a novel apparatus called the ultra - microscope,

which enables the limits Fig. 1. MICROSCOPE WITH FUNNEL TUBE AND CURVETTE,

of ordinary microscopes

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