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By Henry M. Howe

Many direct processes have been proposed for the treatment of oxidized ores of copper by reducing the copper oxide to the metallic state, and by separating it from its impurities by a subsequent fusion. The radical objection common to all the methods which have come to my notice, except those in which sulphur plays the prominent part, is that the very deoxidizing agent which effects the reduction of the copper oxide, inevitably reduces at the same time a very considerable part, if not the whole, of the iron which almost invariably accompanies copper in its ores. The result is that, when the ore is subsequently fused, a very great quantity of the already reduced iron separates from the slag along with the copper, alloying with it, and necessitating costly subsequent operations for its separation. Thus, at Perm, in the Urals," the product of the fusion of ferrnginous copper oxides is a mixture of one hundred and fifty-tive parts of highly cupriferous pig iron with two hundred and fire parts of very impure and ferruginous black copper, containing Pome 10 per cent. of' carbon and iron, though free from sulphur, and of course very difficult to refine. If, in order to avoid this reduction of iron to the metallic state, the reducing action be made feebler, it inevitably results that a considerable part of the copper as well escapes deoxidation; and, consequently, the slags are so rich that it becomes necessary to treat them subsequently in order to recover the copper which they contain. Thus,. in treating native copper, at Lake Superior, where the reducing action is purposely made feeble in order to prevent the deoxidation of the iron, the slags from the first fusion of the ore carry so much copper as to render it imperative to treat them again, which is done in a cupola. And yet, in spite of so far weakening the reducing action as to cause a notable slagging of the copper, a very considerable reduction of iron actually takes place. These are the two dangers which threaten the smelter of oxidized copper ores. If he wishes to avoid slagging his copper, he must have so strong a deoxidizing action as to reduce a great deal of his

Jan 1, 1879

By Rossiter W. Raymond

In the case of The Eureka Consolidated Mining Company v. The Richmond Mining Company of Nevada, recently tried at San Francisco, California, the real defendant was the Richmond Consolidated Mining Company, of London; but this being a foreign corporation, holds its mining property in Nevada through the Nevada corporation of similar name, in which the London Company owns all the stock, except the few shares necessary to " qualify" the American directors. The trial would naturally have taken place in the Circuit Court at Carson City, Nevada, and before a jury. But by stipulation of the parties, the case was tried in San Francisco, before Hon. Stephen J. Field, Justice of the Supreme Court of the United States, Hon. Lorenzo Sawyer, United States Circuit Judge of the Ninth Circuit, and Hon. E. W. Hillyer, United States District Judge, for the District of Nevada. The hearing began July 23d, 1877. The witnesses occupied two weeks, and the argument of counsel three days. Very eminent lawyers were engaged on both sides; for the plaintiff, Messrs. Solomon Heydenfeldt, R. S. Mesick, John Garber, and H. J. Thornton; for the defendant, Messrs. S. M. Wilson, Thomas Wren, and J. J. Williams. The court held the case under advisement until August 22d, when Mr. Justice Field delivered its unanimous opinion in favor of the plaintiff. The action was a complaint in ejectment, and an appeal was taken to the United States Supreme Court. The questions at issue between the Eureka and the Richmond Company in this suit, comprised several points in the construction of the mining law of the United States, and its relation to the customs and regulations of the mining districts, which possess an importance and an applicability far beyond the limits of the case in which they arose. It is my purpose to state these points, the arguments

Jan 1, 1879

By Charles M. Rolker

The Mariposa estate, a grant made by the Mexican Government to Juan 13. Alvarado, during the time when California was still under the dominion of Mexico, was purchased in 1847 by J. C. Fremont, and the United States patent issued to him in 1856. By sale, or its equivalent, money advanced, the property came into the hands of the Mariposa Company, June 25th, 1863, and through a varied existence of work and temporary inactivity, has as yet been kept as an undivided property, and rests at present with the Mariposa Land and Mining Company of California. I pass over this period of 15 years without giving the history of the ups and downs of the estate, partly because it is familiar to many, and also because I think in such a case this paper would assume too much the character of a narrative. The estate is situated in Mariposa County, California, about 170 miles southeast of San Francisco. It begins in lat. 37' 26' 38'' north, and long. 119' 55' west, and runs 6 miles north; thence 69 miles west; thence 5 miles northwesterly towards the Merced River; thence 84 miles southerly; thence 3 miles easterly; thence 1 mile southerly; thence 2 miles easterly; thence 2 miles southerly; thence 2 miles easterly; thence 1 mile southerly; thence 2 miles easterly; thence 1 mile northerly, and thence 2 miles easterly to the place of the beginning; embracing 44,387 acres (70 sq. miles) more or less. To describe this vast estate in detail as to its full geology, its numerous quartz veins, its many facilities to exploit them and work them by cheap methods, would lead me further than I intend to go at present, and I will content myself to describe the latest workings of the company and its immediate field of operations. As long ago as 1860 the late Dr. Adelberg advised the running of an adit from the northwestern edge of the estate at Benton Mills 011 the Mereed River. His object was to undercut the deepest workings of the then paying mines on the estate—the Pine Tree and Josephine. Following this advice, the tunnel known as "River Tunnel " was commenced. Its entrance is in S. 5, T. 4, s. R. 17 E. It is run in

Jan 1, 1879

By Thomas M. Dr. Drown

IN experimenting in connection with Mr. P. W. Shimer (now chemist of the Thomas Iron Company, Hokendauqua, Pa.) on methods for the determination of silicon in pig iron, in order to find one which should be accurate and yet give results in a few hours, I have adopted the following procedure, which, as far as my experience goes, leaves nothing to be desired. About one gram of pig iron or steel is treated in a platinum or porcelain dish with 25 cubic centimeters of nitric acid (sp. gr. 1, 2). When action has ceased, 25 to 30 cubic centimeters of dilute sulphuric acid (one of acid and three of water) are added, and heat applied until the nitric acid is nearly or quite driven off. The heat of a water-bath is sufficient, though the process may be hastened by heating higher on a sand-bath. Water is then cautiously added (as soon as the free sulphuric acid is sufficiently cool) and the contents of the dish heated until the crystals of ferric sulphate are completely dissolved. The solution is then filtered as hot as possible, the residue washed first with hot water, then with 25 to 30 cubic centimeters of hydrochloric acid (sp. gr. 1, 12), and finally with hot water. After drying and igniting, the silica will be found to be snow-white and granular. The following are some results obtained by this method compared

Jan 1, 1879

By John E. Sweet

THERE have already been so many subjects of a purely mechanical nature presented to the Institute of Mining Engineers, that it is unnecessary for me to apologize for adding another to the list. When a new invention, or what is supposed to be a new invention, claiming simply an improvement on the well-known devices, is to be described, it is usual to point out the defects of the old and give a history of the object or the art up to date. But, as no doubt a large proportion of the members of this Institute know as much, or more, about the history and use of the steam-engine indicator than I do myself, I will not further preface the subject, than to remind you that what called for the Richards's improvement on the Watt's indicator was high speed ; that the leading improvement was the reduction of momentum in the reciprocating parts; and that this was accomplished by making the parts lighter, and reducing the travel of the heaviest of them, and consequently the speed and momentum. The use of the indicator has been extended, for the speed of steam-engines and other prime movers has been increased, until one engineer at least, John Cooper, of Philadelphia, says, "I want an indicator that will work up to a thousand revolutions." Mr. Thompson, of the Buckeye Steam-Engine Company, of Salem, Ohio, has improved on the Richards's indicator by another reduction in the momentum, which is done by putting the parallel motion nearer the fulcrum of the pencil arm, reducing both weight and travel. The characteristic feature of the indicator I am going to illustrate is a still further reduction in the same direction, which is accomplished by dispensing with the parallel motion altogether. As is often the, case, in putting a simple idea into shape, some difficulties

Jan 1, 1879

By H. M. Howe

(Read at. the Lake George Meeting, October, 1878.) MANY direct processes have been proposed for the treatment of oxidized ores of copper by reducing the copper oxide to the metallic state, and by separating it from its impurities by a subsequent fusion. The radical objection common to all the methods which have come to my notice, except those in which sulphur plays the prominent part, is that the very deoxidizing agent which effects the reduction of the copper oxide, inevitably reduces at the same time a very considerable part, if not the whole, of the iron which almost invariably accompanies copper in its ores. The result is that, when the ore is subsequently fused, a very great quantity of the already reduced iron separates from the slag along with the copper, alloying with it, and necessitating costly subsequent operations for its separation. Thus, at Perm, in the Urals,* the product of the fusion of ferruginous copper oxides is a mixture of one hundred and fifty-five parts of highly cupriferous pig iron with two hundred and five parts of very impure and ferruginous black copper, containing some 10 per cent. of carbon and iron, though free from sulphur, and of course very difficult to refine. If, in order to avoid this reduction of iron to the metallic state, the reducing action be made feebler, it inevitably results that a considerable part of the copper as well escapes deoxidation ; and, consequently, the slags are so rich that it becomes necessary to treat them subsequently in order to recover the copper which they contain. Thus, in treating native copper, at Lake Superior, where the reducing action is purposely made feeble in order to prevent the deoxidation of the iron, the slags from the first fusion of the ore carry so much copper as to render it imperative to treat them again, which is done in a cupola. And yet, in spite of so far weakening the reducing action as to cause a notable slagging of the copper, a very considerable reduction of iron actually takes place. These are the two dangers which threaten the smelter of oxidized copper ores. If he wishes to avoid slagging his copper, he must have so strong a deoxidizing action as to reduce a great deal of his * Rivot, Prineipes Généraux du Traitement des Minerais Métalliques, i, p. 79.

Jan 1, 1879

By Ellsworth Daggett

THE system of pitwork used with the Cornish pumping engine, and which, for want of a better name, we may call the Cornish system of pitwork, consists essentially of a series of plunger-pumps, situated one below the other, in a shaft or incline, the plungers being operated by a rod called the pitman or pump-rod, which must, therefore, extend from the motor at the surface to the lowest pump. The subject will be best understood by reference to Fig. 1, in which k may be taken as typical of the ordinary plunger-pump, in which S is the suction pipe, u, the lower valve situated in the H piece T; v, the upper valve situated in the valve-box O; I, the mounting-pipe or column through which the water is carried to the surface; L, the plunger-barrel, and P, the plunger working through the stuffing-box, and actuated by the branch rod r, which is attached to the main pump-rod, R. The action of the pump is as follows : On the ascent of the plunger, acting now by suction, the water flows from the reservoir through the valve u, into the barrel, L. On the descent of the plunger, the water is forced up through the valve, v, which acts merely as a check valve, into the pipe, I, through which it is, at each successive down-stroke of the plunger, forced upward until it reaches the next reservoir, from which it is taken by another similar pump, and so on until it reaches the surface or drain-tunnel. The pump is obviously only single-acting, i. e., it acts only during one-half of its entire stroke. The weight of water raised during the up-stroke of the plunger is equal to the weight of a column of water whose base is the area of the plunger and whose height is the mean distance between the plunger-face and the surface of water in the lower reservoir, a distance not usually exceeding 12 or 15 feet, and which obviously cannot under the most favorable circumstances, exceed 25 or 30 feet. The water forced up during the down-stroke is equal to the weight of a column of water whose base equals the area of the plunger and whose height equals the length of the mounting column above the mean position of the plunger-face, say from 150 to 300 feet. Almost all of the useful work, therefore, is done on the de-

Jan 1, 1879

By Henry S. Drinker

THE Butler Mine property is situated in the vicinity of Pittston, in the Wyoming coal-field of Pennsylvania. The coal has been worked out from the fourteen-foot or Baltimore vein for a number of years on part of the tract, the old chambers remaining open as when originally abandoned. This vein outcrops on the Butler property, and is nowhere more than sixty feet below the surface of the ground on the line of the cut-off to be described. Above the fourteen-foot vein and about, say midway, between it and the surface of the ground, there is another small vein or rider of coal, about twelve inches in thickness. The rock between the two veins is a carbonaceous slate, about twenty-five feet in thickness. Above the smaller vein is a bed of sandstone, varying in thickness, but generally not less than from eight to ten feet. This sandstone is also carbonaceous, but the proportion of carbon is much less than in the slate below. Both rocks have been analyzed, and before the next Institute meeting, the writer hopes to be able to furnish the exact proportions. The sandstone is overlaid with debris up to the surface of the ground. Some time during the spring of 1876, it was found that the coal left in the worked-out mine had been set on fire, and that the fire was gradually spreading. Inquiry developed the fact that the fire had originally been started by a woman, who had taken up her abode in an old tunnel leading into the workings. Owing to some delay in the early attempts made to extinguish the fire, it finally gained such headway that no ordinary means were found to be effectual. Finally, Mr. C. F. Conrad, civil and mining engineer, of Pittston, Penna., was called in as consulting engineer. He advised the making of a thorough cut through such portion of the old workings as had not been reached by the fire. It was found by survey that this cut could be limited to a length of about one thousand two hundred feet, as the vein faulted on both sides, and that the greatest depth of the cut would be about sixty feet. Subsequently it was decided to tunnel part of the way, thus saving the deepest portion of the cut. In 1856-7, there occurred a fire in the same mine. Two stone-walls in V-shape running from the apex of the V towards the outcrop, were built to cut the fire off, and these walls were carried as far as the vein had at that time been worked. After the walls were finished

Jan 1, 1879

By Thomas M. Drown

IN the course of some experiments on the analysis of pig iron, I heated, in a platinum crucible, some borings of a graphitic pig iron with sodium carbonate. When the crucible was at a full red heat and the carbonate was thoroughly fused, I noticed a lively ebullition of the mass, and an escape of gas, which burned on the surface. On investigation this gas proved to be carbonic oxide, and on examining the borings in the bottom of the crucible after an hour or two, they were found to be perfectly malleable, although unchanged in general form and appearance. Analysis showed that the carbon was completely removed. I then repeated the experiment, to ascertain whether the silicon and phosphorus were affected, and found that these elements too were largely removed, and could be found in the fused mass as alkaline silicates and phosphates. In order to ascertain whether the removal of the silicon and phosphorus was merely a surface action or whether the reaction really extended into the mass of the iron, I tried the following experiments : A number of bars of pig iron were cast about one foot long and planed down-accurately to one inch section. These were immersed in a large wrought-iron pot full of molten sodium carbonate made by fusing the commercial bicarbonate of soda. Through the kindness of Mr. Frank Firmstone, Superintendent of the Glendon Iron Works, Easton, I was enabled to keep this pot at a reasonably constant high temperature for a long time in one of the hot-blast ovens. One of the bars was removed from the pot every twenty-four or forty-eight hours, according to the rapidity of the action, and after cooling was broken and the fracture examined. The change from pig iron to malleable iron was progressively inwards and always sharp and easily recognized, the rate of progression being in a decreasing ratio with the time. The temperature of the oven had evidently

Jan 1, 1879

By H. Firmstone

Deposits of cadmia, or impure oxide of zinc, are of common occurrence in the upper parts of blast furnaces using ores containing zinc, and were very common in the charcoal furnaces of Virginia working the brown hematite ores found near the Cadent black slate. These deposits were known to the old charcoal founders as "sulphur rings," and the characteristic green flame of burning zinc frequently to be seen at the tymp of furnaces working ores containing zinc, was held by them to indicate the presence of a "sulphur fall." When zinc is burning in considerable quantities at the tymp, the

Jan 1, 1879

By Charles A. Colton

The results of a series of analyses extending over a period of three weeks at the Cedar Point Iron Company's furnace, Port Henry, New York, are given in Tables I and 11. This furnace uses a very pure magnetite and Lehigh and Lackawanna anthracite. The flue leading the gas from the "down-comer" to the boilers was tapped by a 2 inch gas pipe, which carried the gas to the Orsat apparatus. The pressure of the gas not always being sufficient, owing to the small amount made, to force it into the apparatus, I omitted taking samples several days, and with the exception of the last three days of the campaign, made the analyses whenever opportunity offered. I find the Orsat apparatus, as described by Prof. Egleston," to work very well, with one exception. The CO is not absorbed as readily in the ammonia-copper solutiou as he states in his description of the apparatus, as many as 50, and sometimes GO, passes being necessary to absorb all the CO. The power of absorbing rapidly increases as the solution is used, and this would indicate that the more oxygen it contains the quicker will it do the work. Probably the addition of a small amount of some oxidizing agent would remedy this. When the furnace was working in its normal condition, I had no occasion for using the filter, the amount of fume being so small as not to canse any inconvenience. The gas burned with the flame peculiar to CO, and contained just enough solid particles to give it a slight reddish tinge.

Jan 1, 1879

The opening session was held on Tuesday evening, October 23d. Mr. J. F. Lewis, on behalf of the local committee of arrange ments, made a short address of greeting to the members assembled, and then introduced Gov. A. H. Holley, of Lakeville, Conn. Gov. Holley addressed the Institute as follows: Gentlemen, we give you cordial welcome to a mining, manufac turing, and agricultural country, of which we are not a little proud. We welcome you as an association, and as individuals. We invite you to an inspection of our resources, and to our methods of im proving them. We appreciate the results of your efforts in past years, and we anticipate good from your advice and counsel in the future. You are in the vicinity of some of the oldest mining and manufacturing operations in iron in our country. It will be our pleasure to conduct you to a mine which was worked for more than a half century before our country achieved national inde pendence, and to point out to you the spot where the products of this mine were wrought into cannon and shot during the progress of our Revolution. We can show you also a far larger area of mining country than was supposed to exist in this vicinity at that early day. There are, within a radius of thirty miles from this spot, ten mines at least that have been extensively worked, and there are as many more that have been occasionally worked, with a fair degree of success. All the mines that are wrought to any extent produce excellent qualities of iron, while many of them in various combinations produce as good material for the manufacture of steel, car wheels, axles, and many other purposes, as can be found in ally country. The old Salisbury iron retains its reputation for tensile strength unsurpassed, when made entirely from the ore of the old mine. The progress that has been made in the development of these mines since the days of the pickaxe, when the product was trans ported in pounds upon horseback, to those of the steam-engine, which now moves hundreds of tons per day, presents, indeed, a

Jan 1, 1879

By Thomas M. Drown

ZING is, as is well known, very brittle at a temperature of about 210' C. (410' F.), and may then be readily pulverized in a mortar. By sifting it may be obtained of uniform grain. I have been accustomed to prepare products passing through 40, 60, and 80-mesh sieves, and also by bolting through a fine handkerchief. The principal analytical uses to which I have hitherto applied this material are to the reduction of iron directly from the ore by heating it with the pulverized zinc, and the reduction of ferric to ferrous compounds in solution. In the first case the pulverized ore, 0.5 gram or less, is intimately mixed with about ten times its weight of the pulverized zinc (the finer the zinc the better), in a porcelain crucible, and this mixture is covered with about the same amount of zinc. The crncible is then heated at the top of the flame of a Bunsen bhrner, at a dull red heat, for about ten minutes. The crucible should not be covered. When cool, the crucible, with its contents, is placed in a flask treated with hot dilute sulphuric acid, and brought quickly to a boil. The zinc and reduced iron are dissolved in a few minutes and the flask is then tightly corked and allowed to cool. When cool, the iron is directly titrated by potassium permanganate.

Jan 1, 1879

By J. A. Herrick

Jan 1, 1879

By H. Firmstone

DEPOSITS of cadmia, or impure oxide of zinc, are of common occurrence in the upper parts of blast furnaces using ores containing zinc, and were very common in the charcoal furnaces of Virginia working the brown hematite ores found near the Cadent black slate. These deposits were known to the old charcoal founders as "sulphur rings," and the characteristic green flame of burning zinc frequently to be seen at the tymp of furnaces working ores containing zinc, was held by them to indicate the presence of a "sulphur fall." When zinc is burning in considerable quantities at the tymp, the

Jan 1, 1879

By B. W. Frazier

This interesting application of the laws of thermodynamics to metallurgical practice has not been discussed by any writer, within my reading, except the late Prof. Callon of Paris. In his Cours de Machines," Prof. Callon has given a short but lucid discussion of this subject in the admirably clear style for which he was remarkable. Although the interest attached. to the subject is rather theoretical than practical, I have thought that an attempt to explain the mechanical action exerted in the hot-blast oven might not be entirely devoid of utility, especially in the suggestions which it involves. The statement, that the mechanical work performed in heating the blast is, when high temperatures are produced, considerably greater than the work performed by the blowing-engine, may seem incredible to many who are practically acquainted with the subject, appearing, as it does, to conflict with the results of their experience. It is, nevertheless, literally true, and I shall attempt in this paper to prove it, and to explain why it has not rendered itself palpably manifest in practice. Before proceeding to the mathematical demonstration, it will be well to recall to mind the definitions of some terms employed by writers in mechanics and thermodynamics. The actual energy of a moving body, as defined by Rankine, is the work which it is capable of performing against a retarding resistance before being brought to rest, and is equal to the energy which must be exerted on the body to bring it from a state of rest to its actual velocity. The value of that quantity is the product of the weight of the body into the height from which it must fall to acquire its actual velocity.

Jan 1, 1879

By Ellsworth Daggett

Jan 1, 1879

By Prof John E. Church

It is a well-known fact that under similar conditions a ton of pig iron can be made from any ore with less fuel when charcoal is used than when coke or anthracite is employed for heating. The cause of this superiority is entirely undiscovered, and no explanation has yet been offered which has won even temporary acceptance. Such as they are the hypotheses heretofore presented are of two general kinds, and they come from those two divisions of the working force which are so often antagonistic in all professions, the scientific and the practical men. The theory of the scientific men is drawn from the chemical reactions which are known to go on in the furnace, and it is well expressed in a recent paper by Prof. Akerman, of the Stockholm (Sweden) School of Mines. It makes the superiority of charcoal as a fuel in the blast furnace to depend upon its quick and thorough reduction of carbonic acid. This property belongs to charcoal in virtue of its porous structure. Its cells have a diameter of only one twenty-four hundredth of an inch, and one grain of charcoal has been computed to have a surface of two and four-tenths square feet. According to the theory in question, carbonic acid is formed by the first impact of the air upon the fuel; but in charcoal furnaces the acid is immediately reduced to oxide by taking the necessary amount of carbon into combination, and the gas reaches its highest reducing power even in the near vicinity of the tuyeres. Coke, being harder, does not produce so strong a reducing gas in that part of the furnace. Carbonic acid is formed as in the case of charcoal, and remains longer before its reduction to oxide is completed. Anthracite is the

Jan 1, 1879

THE first session was held in the small hall of the Academy of Music, on Tuesday evening, February 18th, 1879. The proceedings were opened by the reading, by President Eckley B. Coxe, of the following Address : SECONDARY TECHNICAL EDUCATION. Technical education is a subject to which both the American Institute of Mining Engineers and the American Society of Civil Engineers have of late years given much attention, and deservedly so. We all remember the admirable address of our former President, Mr. Holley, at the Washington meeting, upon this subject, and the very interesting reunion of the two societies in Philadelphia for its discussion. The problem to the solution of which the meeting devoted its attention was, "Shall the practical education of the engineer in the mine, in the rolling-mill, in the workshop, or in the field, precede, be contemporaneous with, or follow his theoretical studies in the technical school ?" I do not propose to add anything to what was so admirably said by so many of our leading engineers on that occasion ; but I shall ask your attention to another question in technical education, which seems to me equally worthy of our consideration, and which, I am sorry to say, has as yet attracted but little attention in this country. It is, "Shall the apprentices (I call them so for the want of a better general name), who are growing up and learning their trades in and around our mines and works, and from whose ranks the master mechanics and foremen of the future must be taken-shall they be provided with some means of obtaining as much theoretical training as may be necessary to enable them properly to understand the various processes and operations that they may be called upon to superintend, and not be obliged to pick up, as best they may, here a little and there a little truth mingled with much error?" In the former case, those who have the ability and industry to avail themselves of the advantages that should be offered to them would fit themselves to become real foremen, men who would understand and appreciate the true engineer and his methods. Of late years the young men of this country who have wished to enter our profession have had great facilities offered to them for so doing ; there have been undoubtedly great improvements in the methods of instruction; and although I am very far from imagining that no further progress can be made, or is demanded, yet I feel sure that

Jan 1, 1879

By R. H. Thurston

THE writer became convinced, many years ago, that the generally accepted values of the coefficient of friction for lubricated surfaces were not applicable to such heavy machinery as he had been called upon, in the course of professional work, to design, to construct, and to operate. Experience frequently seemed to indicate, also, a wide departure, in such cases, from the accepted "laws of friction." In the year 1869, or earlier, he invented an apparatus to redetermine these laws and these coefficients for a wide range of temperatures, pressures and velocities. The construction of the machine was delayed, however, some time, and no experiments were made for several years, when, finally, the construction of the apparatus was commenced in the workshops of the Stevens Institute of Technology, and experiments were begun in the Mechanical Laboratory organized by the writer in connection with the Department of Engineering. These machines have now been in use about five years, and have furnished an immense amount of valuable information. Those now in use are of two styles: one designed and built by the Class of 1877, Figs. 1 and 2; the other a much larger machine, Figs. 3 and 4. The first has been already frequently described,* and a working drawing of the second has been also published.† For convenience, engravings of both are herewith reproduced. In the “'77 machine,” a journal, F, is made on the overhung extremity of a shaft carried in the two bearings, B B'. This journal is grasped by brass boxes which are carried in a pendulum, II H. They are forced against the journal by a screw which compresses a coiled spring with a pressure which is read off on the scale, N H. A weight at the lower end of the arm, at I, gives it the necessary resistance to deflection. The angle of deflection is measured on the * In Scientific American, Railroad Gazette, Jour. Frank. Inst., Johnson's Cyclopaedia, Knight's Mechanical Dictionary, etc. † Railroad Gazette, Jan. 18th, 1878, p. 25.

Jan 1, 1879