MILLS, COLUMBIA, S. C.

ON Tuesday, April 24, there was started in Columbia, S. C., a power transmission plant of exceptional interest, in the development of a new and important field in the application of electric motors to the manufacture of textiles.

The Columbia Mills Company (an organization composed mainly of New England capital) have had in contemplation for some time the erection of a large cotton mill in Columbia, S. C., to take advantage of the situation as regards supplies, labor and a fine water power close to the town. Last year this enterprise was pushed to a conclusion, but on making the detailed plans for the work, it was found that owing to the situation of the power and land available for the mill purposes, it would be highly advantageous not to erect the mill directly at the power, but to transmit the energy for driving at a distance of about 800 feet. In connection with this, of course, all well known plans for delivery of power were carefully canvassed by the company, and by Lockwood, Greene & Company, their engineers.

After careful consideration of all the various electrical and mechanical systems, the triphase system of the General Electric Co. was selected, with special view to the uniform speed to be obtained in the motors, and the total absence of commutators and collecting devices which might cause troublesome and dangerous sparking. To further increase the efficiency of the system, it was decided to couple the dynamos to their turbines directly, although the available head (25 feet) introduced a serious limitation in the possible speed.

The total amount of power to be transmitted was over 1,000 H. P. and it was decided to divide this into two units at the generating station. Consequently two special slow-speed triphase generators were designed to meet the requirements of the case. One of these machines of 500 K. w. capacity is shown in Fig. 1. It has forty poles and operates at a normal speed of 108 revolutions per minute, giving thirty-six cycles upon the line, at a voltage of about 575 at the dynamo terminals.

The armature is ten feet in diameter, and is of massive construction. It is of the iron-clad type and is wound with a single

planking, protected by pitch and asphalt, the bare wires being placed in position in a bedding of asphalt. The conduit thus constructed rests on a blind drain, and is carried across the canal to the power house under a bridge which is there erected.

bar per slot, heavily insulated, a construction which gives practical freedom from burnouts and other electrical difficulties. The total weight of the machine is about 100,000 pounds.

Two of these huge machines were completed in the early part of the present year and shipped to Columbia, where the turbines were nearly ready to receive them. The power plant consists of two pairs of 48 inch cylinder gate Victor turbines made by the Stilwell-Bierce & Smith-Vaile Co., (illustrated in our last week's isuse), which are directly connected to the generators. The generating

operated from the floor by means of a lever thrust into the switch Socket.

All interior wiring is in conduit tubing, and the switches are boxed in. In addition to the motors, several hundred lights are wired in the mill, and can be operated either from the main circuit or in part from either of the two 25 H. P. exciters which were provided with surplus capacity with this object in view. The mill is not yet all in place, but on April 24, the big generators were started and the motors given a preliminary spin.

The combination of a field magnet outside the armature rotated by means of a spider attached to the shaft, the spider and field forming a bell-shaped revolving field magnet, with a stationary armature.

Dynamo Electric Machine, G. Forbes, Niagara Falls, N. Y., 518,945. Filed Aug. 17, 1893.

Claim: The combination of an armature having parallel notches with two types of coils or solenoids having corresponding parallel sides, the ends of the coils of the second type being bent over the ends of the armature and passing within and clear of the colls of the first type.

Construction of Solenoids or Coils of Wire Used in Electric Machinery, G.
Forbes, Niagara Falls, N. Y., 518,946. Filed Aug. 17, 1893.
Claim 1 follows:

The combination of a solenoid or coil with a close fitting casing, having an inlet and outlet for oil with a pump for maintaining a forced circulation of oil.

Field Magnet for Electric Machines, A. Schmid, Allegheny, Pa., 519,097. Filed Dec. 7, 1889.

Employs field poles composed of lamina of sheet iron with a frame of cast iron cast about them and certain of the laminæ projecting into the cast iron frame a greater distance than the others.

Self Exciting Constant Potential Electric Generator, A. Schmid and B. G. Lamme, Pittsburgh, Pa., 519,098. Filed Feb. 20, 1890.

Employs main armature coils wound about the core, supplemental regulating coils connected in series with the main coils and others connected with the supplemental coils and a conductor for connecting the supplemental coils with the field exciting coils.

Electric Motor, F. E. Herdman, Indianapolis, Ind., 519.116. Filed July 19, 1892.

The invention consists in giving to the fields excessive strength at the time the current is thrown on the motor and reducing their strength as the motor increases its speed.

Regulator for Electric Motors, F. E. Herdman, Indianapolis, Ind., 519,120. Filed Apl. 16, 1892.

Similar in its object to No. 519,116.

Controlling Device for Electric Motors, F. E. Herdman, Indianapolis, Ind., 519,121. Filed July 19, 1892.

Similar in its object to No. 519,116.

Commutator Brush, R. Kersberg, Hohenlimburg, Germany, 519,188. Filed Jan. 8, 1894.

Composed of a cloth of wire spirals screwing into one another.

Electric Motor, E. E. Ries and G. J. Scott, Baltimore, Md., 519,272. Filed July 27, 1893.

Consists of several groups of sectional, laminated, and interlaced field magnets circularly arranged, a concentric sectional laminated armature, circuit connections, and a commutator,

Electric Generator, W. Baxter, Jr., 519,280. Filed May 12, 1891.

Claim 4 follows:

The combination of the frame, the field magnets mounted on the frame, the shaft fixed rotatably in the frame, the armature and commutator mounted on the shaft, the sleeve between the armature and commutator and the nut on the shaft, impinging against the commutator, whereby said armature and commutator are secured.

Electric Motor or Generator, W. Baxter, Jr., 519,281. Filed May 12, 1891. Relates to certain mechanical details of construction and more especially to the commutator and brushes,

Heating:

Electric Heater, S. B. Jenkins, Boston, Mass., 518,013. Filed March 31, 1893. Lamps and Appurtenances:

Electric Arc Lamp, J. B. McKeown, Cleveland, O., 519,045. Filed Feb.

23. 1894.

Relates especially to the mechanism for feeding and controlling the carbon rods.

Incandescent Electric Lamp, F. S. Smith, Pittsburgh, Pa., 519,099. Filed Nov. 29, 1892.

The invention consists in employing for the stopper a form of glass having a co-efficient of expansion substantially equal to that of iron, of which the leading-in wires are composed.

Electric Arc Lamp, J. C. Fyfe, Chicago, Ill., 519,283. Filed Dec. 29, 1893. Relates to the feeding mechanism of arc lamps using disc carbons. Miscellaneous :

Electric Elevator, F. E. Herdman, Indianapolis, Ind., 519,117. Filed Oct. 20,

1892.

Troiley for Electric Railways, G. W. Hooper, Rochester, 518,952, Filed June 1, 1893.

Relates to certain mechanical details of the trolley and yoke.

Electric Railway Conductor Support, J. C. Henry, Westfield, N. J., 519,115. Filed Sept. 27, 1889.

Employs two working conductors, one being divided and the other yieldingly supported normally above the point of division so as to pass through the division on the passage of the trolley.

Electric Railway, W. B. Purvis, Philadelphia, Pa., 519,291. Filed Apl. 14, 1893.

Employs a magnetizable conductor within a closed conduit the upper portion of which is uninsulated, and magnetic means for raising the conductor into contact with the uninsulated portion of the conduit as the car passes. Telegraphs:

Relay, H. S. L. Verley, Hoboken, N. J., 519,142. Filed Jan. 13, 1894.

The invention consists in combining with the relay an auxiliary electromagnet in circuit with the primary magnet and adapted to act on the contact arm simultaneously with the primary magnet. Telephones and Apparatus:

Telephone, E. V. Kolbassieff, Cronstadt, Russia, 518,959. Filed Sept. 21, 1893. A transmitter and receiver especially adapted for use in divers' helmets.

LEGAL NOTES.

THE INJUNCTION AGAINST THE OCONTO CO. SUSTAINED.— EDISON ELECTRIC LIGHT CO. vs. ELECTRIC MFG. CO.

THE appeal of the Electric Manufacturing Co. of Oconto, Wis., vs. The Edison Electric Light Co. (General Electric Co.) from the decision of the U. S. Circuit Court, which granted the Edison Co. an injunction pendente lite, came up before the U. S. Circuit Court of Appeals, which has just rendered a decision sustaining the decision of the court below, which thus enjoins the Oconto Co. from manufacturing incandescent lamps until final hearing. In the opinion which is written by Judge Jenkins, the court holds with Judge Colt, in the Beacon case, that where the validity of a patent has been sustained by prior adjudication, and especially after a long, arduous and expensive litigation, the only question open upon motion for a preliminary injunction in a subsequent suit against another defendant, is the question of infringement, the consideration of other defenses being postponed until final hearing; the only exception to the rule being where the new evidence is of such a conclusive character that, if it had been introduced in the former case, it probably would have led to a different conclusion.

The court then discusses the alleged anticipation of Goebel and the evidence submitted to sustain the claim. The conclusions reached by the court are, that without assuming the story of Goebel's invention to be untrue, it is surrounded by such an atmosphere of improbability that until it is thoroughly sifted and sustained upon final hearing, the claim ought not to be allowed to stand in the way of a patent which has already safely passed the ordeal of judicial scrutiny.

the field eLECTRIC RAILWAY PATENT Declared invALID. ELEC. RY. CO. OF U. S. vs. JAMAICA & BROOKLYN RY. CO. On May 3 Judge Townsend of the U. S. Circuit Court for the Eastern District of New York rendered a decision in the case of The Electric Railway Co. of the United States against the Jamaica and Brooklyn Railway Co., in favor of the defendants. This suit was brought under the famous patent granted to Stephen D. Field, July 16, 1889, No. 407,188, the principal claim of which reads as follows:

The combination of a stationary dynamo electric generator driven by a suitable motor, a circuit of conductors composed in part of an insulated or detached section of the line of rails of a railroad track, a wheeled vehicle moving upon and along said insulated section of track, an electromagnetic motor mounted upon said vehicle for propelling the same and included in said circuit of conductors, and a circuit controlling device placed upon said vehicle.

Judge Townsend holds that the evidence shows that the elements of the combination were not new to the art and that they were embodied in a prior patent issued to Clark.

The suit was defended by the General Electric Co.

ANOTHER REFUSAL TO ENJOIN THE BUCKEYE ELECTRIC CO. Word reaches us from Cleveland as we go to press that Judge Ricks has again refused the motion of the General Electric Co. to enjoin the Buckeye Electric Co., for incandescent lamp infringe

ment.

M. S. SHAPLEIGH has brought suit before Judge Dallas in the U. S. Circuit Court at Philadelphia against the Chester Electric Light and Power Co. for infringement in the use of cut-outs similar to those made under his patents by the Emerson Electric Mfg. Co. of St. Louis.

MR. W. S. HADAWAY, JR., is to lecture before the New York Electrical Society at Columbia College, on May 10, on some features of electric heating. The lecture promises to be one of the most interesting of a very successful season.

ON the evening of May 4, Mr. Alexander Jay Wurts, of the Westinghouse Co., delivered a lecture at Columbia College before the electrical engineering students on the subject of" Non-Arcing Lightning Arresters." Mr. Wurts explained the theory of his now well known zinc cylinder arrester and showed a new type of apparatus intended for street railway circuits. The lecture was illustrated by a number of striking experiments and the arresters were shown in operation. Mr. Wurts also delivered the same lecture before the Boston Society of Arts, on April 30.

Trade Notes and Novelties

AND MECHANICAL DEPARTMENT.

THE BAIN ARC MACHINE WITH AUTOMATIC REGULATOR.

THE accompanying illustration represents a constant current arc light dynamo with regulator, the invention of Mr. Forée Bain, and now being manufactured by the Great Western Manufacturing Co., of Chicago.

As will be seen, the field is of the salient pole, horse-shoe type, cast in one piece. The armature is large in diameter and is very strongly built; it is of the Gramme type, having a large number of independent coils, by means of which a very steady current is produced. The brushes are of carbon and are so placed as to produce a constant lap on the commutator.

The automatic regulation is performed by the movement of the brushes around the commutator. The motor device employed for the movement of the brushes is operated by means of a small belt connecting the armature shaft to a larger pulley, as shown in the engraving; by the rotation of this large pulley the ratchet bar is reciprocated. The ratchet bar carries a small ratchet, which is held out of engagement with the ratchet wheel by means of two elliptical springs on either side of the armature, placed between two pairs of electromagnets. The ratchet wheel is connected by means of a shaft, not shown in the engraving, to a small pinion which engages with gearing cut on the rocker arm which carries the brushes.

If the external resistance is such that the current may be main. tained with a lower voltage than the maximum of the dynamo, the current tends to rise above its normal value and the director is deflected to a still greater angle, which causes the contact controlling the electromagnets on the left hand side of the electromagnetic armature to be closed; and at the same time, the contacts controlling the electromagnets on the left hand side of the armature are opened, allowing the current to pass through them, and they attract the armature, which causes the double ratchet to engage in the ratchet wheel in such a way as to cause it to move in an opposite direction from that just described; by this means the brushes are moved forward on the commutator to a point where the E. M. F. is just sufficient to maintain a constant current through the resistance contained in the circuit.

When the machine is operated through a circuit which remains substantially unchanged the brushes remain quiet and the only moving device is the crank wheel and the reciprocating bar, which holds the ratchet since the ratchet is held out of engagement until one or other pair of the electromagnets are energized. The director device may be adjusted at any time while the machine is operating so that it will maintain a constant current at any value desired within a range of 20 per cent. of its rated capacity, that is to say, it may be adjusted to deliver a current 20 per cent. larger or 20 per cent. smaller than the rated capacity of

the machine.

The regulator is said to be very sensitive and at the same time very positive in operation, and to maintain a constant current independent of the number of lamps in circuit. The machine may be run indefinitely on an absolute short circuit without injurious results.

The machine is very substantially constructed, has self oiling bearings, and is self contained, no outside device being necessary.

The "directing" device, shown under the connecting board, which is mounted on top of the dynamo, consists of a small iron bar suspended immediately over the armature. This "director" controls two contact devices, shown on the top of the connecting board, which operate to short circuit both electromagnets when the machine is working under normal conditions and is producing a current at which it has been adjusted. The thumb nut, on the right hand side of the engraving and just below the connecting board, illustrates a means of adjusting the strength of the current while the machine is in operation; this thumb nut is connected by means of a bar and a spiral spring to the director bar, and tends to hold it in a position opposite to the position that the bar would assume by an increase of current in the armature. The operation of the device is as follows:

When the machine is first started the spring connected to the controller pulls the controller bar into position approximately parallel with the path of the current circulating in the wires of the armature. When the current in the armature has assumed a given value, which has been predetermined by the tension of the spring, the deflecting bar is deflected from a line parallel with the current in the armature to a line slightly at an angle therewith. Before it has been deflected, however, to the position described, the contact above the deflecting bar has been opened by the deflecting bar being out of position it later assumes. When the machine is operating under normal conditions, an open contact above allows the current to pass through a pair of electromagnets on the right hand side of the armature, situated between the two pairs of electromagnets. The current circulating in this pair of electromagnets attracts the armature toward them and engages the ratchet device in the ratchet wheel and quickly gigs the ratchet wheel, in this case, in clockwise direction, which moves the brushes to a point on the commutator corresponding to the highest potential.

MR. GIDDINGS AND THE BROWNELL & CO.

MR. C. M. GIDDINGS, who has been for the past six years in charge of the Sioux City Engine Works, has recently connected himself with The Brownell & Company, of Dayton, Ohio, manufacturers of boilers and engines. They have bought the exclusive right to manufacture under his patents, and have established a department of engineering under his supervision. The Brownell & Company will make a specialty of high grade automatic engines, both simple and compound, and have purchased the entire stock of drawings, patterns, finished and unfinished automatic engines of the Sioux City Engine Works. These engines are well known in the trade as the Russell single valve automatic. Mr. Giddings was in charge of their engineering department for four of the seven years he was with them, and while there designed and patented his governor and valve. The highest grade of workmanship and finish will be maintained in these engines, which have already obtained a high standing for their close regu lation. The Brownell & Company have superior facilities in their boiler manufacturing department, and have recently added to their boiler shop equipment a set of 20 foot rolls, 18 inches in diameter, capable of rolling the heaviest plate and making 20 foot boilers in two sheets.

A COMPACT WESTINGHOUSE PLANT IN PITTSBURGH, PA.

AN electric generating plant has lately been installed in the new building of Heeren Brothers & Co., Pittsburgh, Pa., the installation being very compact and complete throughout for one of its size.

The outfit comprises two "Kodaks," consisting of two 10-18x10 Westinghouse compound engines and two Westinghouse 56 K. W. multipolar generators, coupled direct to each other with the well known Westinghouse flexible couplings. The engines and generators run at a speed of 320 R. P. M. The switch board is made with the main portion across the end of the room, with an angle at one side. This construction became necessary on account of the limited space; the main switches and all instruments are on the angle portion and all circuit switches, cut-outs, etc., are on the main body of the board. The board is of hard wood with all instrument mountings of marble. The whole installation is artistically and finely finished, and is considered the finest plant of its size yet installed in this section. When in operation the engines and generators are absolutely noiseless, due to the absence of belts. The space occupied by the two "Kodaks" and angle switch board is only 16 by 19', with ample space around and between each rig for handy operation of both dynamos, engines and switchboard apparatus.

It was found necessary when constructing one of the foundations to bridge over a building support footing, which was done by the use of heavy I beams carried across over this footing. This construction has proved very satisfactory, as there is no vibration felt in the building when either or both of the "Kodaks" are in operation.

The installation was made by the Westinghouse Electric & Manufacturing Co., and Westinghouse, Church, Kerr & Co.

ELECTRICAL APPARATUS AND STEAM ENGINE PLANT

WANTED BY THE WEST VIRGINIA UNIVERSITY.

THB WEST VIRGINIA UNIVERSITY is building a Mechanical Laboratory adjacent to the Mechanical Shops, in which the light, heat and power plant of the University will be installed. Having this plant all under the same roof in the Department of Mechanical Engineering greatly increases the facilities for instruction, as the whole plant will be available at any time for experimental work and special testing and investigation.

The equipment will include a storage battery plant, arc and incandescent dynamos and motors, electrical testing and measuring instruments, simple and compound engines, installed so as to work as a triple expansion engine of 100 H. P.; exhaust steam and independent jet and surface condensers, compound pumping engines for reservoir service and duty tests; high pressure sectional boilers, set for coal and natural gas firing; and the present equipment of standard engineering testing and measuring instruments and accessories will be materially increased.

The University is located at Morgantown, West Virginia, on the Monongahela River, and on the new link of the Baltimore & Ohio R. R., connecting the Pittsburgh and Wheeling lines.

The University is ready to receive bids and estimates on all the above apparatus, which may be addressed to Prof. Wm. S. Aldrich, Director of the Department of Mechanic Arts.

HARRY S. SMITH & CO., LTD.

About this season of the year the wise man begins to bethink him of the discomfort of the hot summer days and nights, and to provide for the future. The first thing to do, of course, is to buy an electric fan for each room or office, and have it ready to turn on as soon as it is needed. To lessen the burden of choosing the style or make most suitable to each case, Messrs. Harry S. Smith & Co., Ltd., of 607 Chestnut street, Philadelphia, have issued a twelve page catalogue presenting several types of fans and fan motors for both direct and alternating currents, for which they have the agency. Among these are the Crocker-Wheeler and Ries & Scott fan motors in various styles, and the Smith and La Rue ventilating fans.

On the last page of the catalogue also appears a well executed and life-like illustration of the Colvin desk telephone set, manufactured by the Interior Telephone Company of 203 Broadway, New York, and for which Harry S. Smith & Co. are the Philadelphia agents.

THE NEW BRUSH STATION, BALTIMORE, MD.

The new electric light and power station for the Brush Electric Light Co., of Baltimore, Md., will be one of the finest in the Southern states. The boiler room is 83 ft. wide by 129 ft. long. The dynamo room is 130 ft. square,-the floor space in the latter being entirely free from posts. The roofs are designed and built by the Berlin Iron Bridge Co., of East Berlin, Conn., and are made entirely of iron, covered with their patent anti-condensation corrugated iron roof covering.

CUTTER'S ARC INSULATOR.

THE NEW HILL SWITCH.

the handle is attached) by a single bolt or screw in each blade, there was nothing to prevent the twisting of the blades, thus allowing one to move in advance of the other, and as the two or more poles would not break in unison, excessive flashing would result.

To overcome this defect and produce a more mechanical and substantial device, the outer ends of the blades and yoke have been broadened, and two screws or bolts inserted, thus securing the parts so rigidly that the blades must at all times move in unison, and all the blades leave the contacts at the same instant.

The second feature consists in backing up the regular flexible contacts B, by what they term "reinforcing plates," A. It has heretofore been the custom to use nothing but the copper strips B, and these of necessity being flexible were liable to spring apart by constant usage, thus impairing the contact and causing the parts to heat. By the method shown the flexibility is maintained, and on account of the reinforcing plates the flexible contacts are always held in proper position, consequently the electrical connection between blade and contact is always kept perfect.

It will also be seen that the carrying capacity of the flexible copper plates B, is increased by the reinforcing plate A, to the maximum of any other part of the circuit, preventing loss of current in the switch and heating and destruction of its contacts. Hundreds of these switches are now in use, and the value of the inventions embodied in them are becoming more and more apparent as the test of time is applied.

MOST arc lamp users have felt the need of a good device for insulating the frame of the lamps from the hoisting rope or the supporting arm, So as to reduce the chances for grounds in wet weather. Many of the existing arc insulators and break insulators are readily covered with a film of moisture on rainy days, and therefore George Cutter, of Chicago, has devised a new form which seems to avoid this source of trouble. Our illustration shows the new type which is only twice the size of the cut. The insulator proper is made of hard rubber which is less likely than glass to have a film of moisture form on its surface. The double petticoat gives a good water drip, so that the moisture cannot readily creep across the lower surface. All parts are designed for ample strength, the eye at the top and the snap-hook at the bottom being threaded into bushings which are moulded directly into the rubber. The whole device seems well suited to the needs of the case and Mr. Cutter is already finding a good market for it.

Cutter's Arc Insulator.

THE MATHER ELECTRIC COMPANY.

THE MATHER ELECTRIC COMPANY report the following sales of apparatus outside of their railway business during ten consecutive days recently:-Mass. Hospital for the Insane, Northampton, Mass., one 350 light and one 600 light dynamo; Eastern Yacht Club, Boston, Mass., one 250 light dynamo; Wayne County House, Wayne, Mich., two 20 K. w. direct connected dynamos; S. N. Blake, Elmira, N. Y., one 350 light dynamo; Sherman & Kopf, Detroit, Mich., one 250 light dynamo; George Whitney Woolen Co., South Royalston, Mass., one 100 light dynamo; Syracuse Herald, Syracuse, N. Y., one 250 light dynamo; Union Central Life Insurance Building, Buffalo, N. Y., one 450 light and one 250 light dynamo ; Patent Cereal Company, Geneva, N. Y., one 150 light dynamo; Crane Bros., Westfield, Mass., one 50 light dynamo; Henry Reinhardt, New York City, one 150 light dynamo; Boston Ferrule Company, East Boston, Mass., one 50 h. p. slow speed motor; Phelps Publishing Company, Springfield, Mass., one 50 h. p. slow speed motor; in Springfield two 15 h. p. and one 1 h. p. motors, and 16 other motors, from 1 to 15 h. p., in various places.

complete, about 400 lbs. Sixteen cells compose a set, which is in use on the wagon while the remaining set is being charged.

The wagon is wired with extra heavy rubber-covered No. 12 wire and a No. 14 specially made black silk cord runs from the wagon to the horses. The wagon carries fifteen 28 volt 16 c. p. DeKhotinsky lamps in Edison sockets, and each of the four horses carries two 30 volt 16 c. p. lamps of the same make in Swan sockets which are fastened between the ears and on the saddle. Bryant switches control the four circuits, two on the wagon and one each on the leaders and wheelers. The batteries are charged from the theatre plant in a small house built for the purpose in the rear of the main building.

This outfit has been in charge of Mr. R. Burbank, electrician of the theatre, and has been running very satisfactorily since it

FIG. 2.-BATTERIES IN KEITH'S ELECTRIC SHOW WAGON.

was brought out in September, 1893. The wagon has been used in Boston, Providence, Philadelphia, Brooklyn, and New York, and has made extended trips through the suburbs of these cities. As an advertising novelty, it has been a great success and never fails to attract admiring attention.

MR. D. A. STARR, well known from his long connection with the Royal Electric Co., of Montreal, Canada, has severed his direct connection with that company. He has temporarily opened an office in the Board of Trade Building, Montreal, and has the best wishes of numerous friends for his future success.

MICANITE CLOTH.

It is always advantageous, in advertising a really good thing, to exhibit the article itself, rather than deplete the gray matter of one's brain thinking up a list of superlatives to adequately describe it. Besides, it is easier, and this is a labor-saving age. It is impracticable, perhaps, in some instances, as it would be annoying, to find one's desk covered each morning with generators, motors and engines sent out as samples by the manufacturers, and it is manifestly impossible in the case of inferior goods.

The Mica Insulator Co., of 218 Water street, is fortunate in manufacturing a material not too cumbersome to be thus advertised and so good that it can be allowed to speak for itself. The company has sent to each of its friends a sample of "Micanite cloth," which for general purposes is a most useful form of insulation. It has recently been greatly improved and is now said to be non-absorbtive, to remain flexible indefinitely and to combine a maximum amount of pure India mica with a minimum of thickness. It is put up in rolls 32 inches wide and 16 feet long, and can, of course, be cut into any shape to suit any conditions. A pair of trousers of this material which we are now wearing have retained their creases perfectly.

THE CHICAGO SPARK ARRESTER.

THE METROPOLITAN ELECTRIC COMPANY is introducing a new arc lamp spark arrester, known as the "Chicago" and shown in the accompanying illustration. It is made to fit any system, either single or double carbon lamp. It is fastened by an adjustable clamp to the lamp holder, inside or outside, and is arranged to open out, separating in the centre, so that, once in position, it is permanently fastened, and is easily opened to each side whenever necessary to trim the carbons or change the globe.

The cover is arranged to automatically open and close, as the carbon holder passes downward through two mica plates, which are hinged and balanced, and close immediately after the holder has passed through. While held at an angle during the time that

THE CHICAGO SPARK ARRESTER.

the holder is gradually being lowered by the consumption of the carbons, that is, about an hour, the device is so constructed that a draught is established, which draws the sparks away from the carbons, and the hood of the arrester is so placed that the sparks cannot escape.

It is said that experts who have examined the "Chicago" spark arrester pronounce it absolutely the best thing of its kind on the market to-day, and predict its very general use.

THE WHITE ADJUSTABLE LAMP HOLDER.

The adjustable lamp holders for incandescent lamps, manufactured by O. C. White & Co. of Worcescester, Mass., and fully described in their illustrated catalogue, will be found a great convenience in draughting rooms, machine shops, factories, offices and wherever it is necessary or desirable to change the position of the light easily and quickly.

The foundation is a sectional ball and socket joint on a base suited to the required position, either the ceiling, wall, floor, column or corner being available. This joint has received many awards and medals for its originality and value, especially from the Franklin Institute of Philadelphia, and the Mass. Charitable Mechanics' Association of Boston. From the joint runs a tube of firm metal to a swivel joint which carries another metal tube, usually shorter than the first. This joint allows the extension and rotation of both arms in any direction. The conducting wires pay through the short arm, which at its far end carries the lamp (with its shield and shade if wanted) by a third joint which allows the lamp to be inclined at any angle.

The combination of tubes and joints is a close copy of the human arm, with a ball and socket joint at the shoulder, a swivel joint at the elbow, and a wrist joint, and like the human hand the holder can bring its burden into any position within its sweep. Each joint of the mechanism has an elastic pressure, easily adjusted, which is enough to hold a heavy lamp and shade quite firmly, and still will yield to a moderate force when it is desired to change its position. All the working parts are of metal, made interchangeable; insulating bushings protect the conducting cords, and ample provision is made for any possible wear by prolonged

use.