THE ROLLASON WIND MOTOR FOR ELECTRIC LIGHTING.

AN exhibition was given at Willesden Junction, near London, recently, of an electric generating plant operated in connection with a novel type of windmill known as the Rollason wind motor. From the illustration, for which we are indebted to the London Electrical Engineer, it will be

ing an Elwell-Parker dynamo, which is used to charge accumulators.

The electric details which permit of the batteries being charged under variable speed of the dynamo are withheld from publication.

ELECTROSTATIC INDUCTION MACHINE WITHOUT SECTORS.'

SINCE bringing out his first electrostatic machine, in 1883, Mr. Wimshurst has made a number of improvements on it. The Wimshurst machine, as is well known, consists of a disc of insulating material provided with sectors radially arranged, but a simplifieation of the machine, which is claimed also to increase its output, has been recently made by M. Bonetti. This has been effected by doing away entirely with the metallic sectors and increasing the number of the rubbing brushes. This is the practical realization of a suggestion made by M. George Pellissier, in 1891, in the Journal de Physique.

The disc machine constructed according to this plan is shown in Fig. 1. This has all the elements of the Wimshurst machine minus the metallic sectors, but having a greater number of brush holders which allow the brushes to slide upon the diametrical conductors. The discs may be either of glass or hard rubber. The machine is not selfexciting, the excitation being produced by rubbing one of the plates with the finger covered with amalgam; but once accomplished the direction of current does not change. Reversal of the current during action is only produced by rubbing the other plate at a symmetrical point. This constancy of direction of the current and the ease with which it can be rapidly and surely reversed constitutes one of its special advantages in electro-therapeutics.

THE ROLLASON WIND MOTOR FOR ELECTRIC LIGHTING.

noticed that it is a horizontal arrangement contained in a skeleton turret. From the top to bottom of the centre or axis of the turret is provided a vertical steel shaft; this has attached to it five concave sails, which revolve on radius rollers immersed in oil. On these sails are fixed a number of inclined ridges or planes, which it is claimed. deflect the force exerted by the wind to their peripheries. Between the sails and the shaft is arranged a considerable open space which allows the wind to actuate simultaneously three sails out of the five. Outside the sails is a framing, or screen, supported by six radial or cross arms, which are bolted to a centre bearing, which is free to rotate independently of the sails. A second vertical shaft from the top of the shield is continued through the roof of the turret, and to this is fixed a vane, so that when the direction of the wind changes, it moves the shield into the correct position for only the concave sides of the sails to catch the wind. On the top of the sail shaft is fixed a cup containing a quantity of oil, within which are rollers, by which the shaft actuates the shield. The weight of the vane shaft is carried on an independent roller bearing fixed in the roof of the turret. The whole weight of the sails and framing carrying the shield is thrown to the centre bearings on the bottom of the turret, which thus gives to the working parts of the motor the desired balance.

The motor is 20 ft. in diameter, and is erected on an open iron structure 30 ft. high. The power developed by the motor is transmitted by a vertical shaft running down the centre of the supporting framing into a wooden shed on the ground. Suitable gearing is provided on the lower end of the shaft for working the pulleys actuating by belt

FIG. 1.-BONETTI WIMSHURST MACHINE WITHOUT SECTORS.

The output can also be varied within wide limits, either by reducing the number of contact brushes or in displacing their points of contact on the disc. When the whole surface of the disc is brushed by metallic points the output is a maximum. As measured by the Lane electrometer, the output according to M. d'Arsonval, is three times as great as that of a Wimshurst machine of the same dimensions provided with sectors. In displacing the brushes so that

1. La Nature.

they touch the same zone the output is reduced in proportion to the surface brushed.

The principle of the Wimshurst machines without sectors has been also applied to a more powerful machine, shown in Fig. 2, in which the discs are replaced by two concentric cylinders of hard rubber, the mean diameter of which is 50 centimetres and height 50 centimetres. The two cylinders, separated by only a few millimetres are mounted on two thick ebonite discs fixed on concentric spindles with ball bearings and driven by a friction gear. A series of

EVERY fire which takes place in any city of considerable size is recorded as to location, loss, amount of insurance carried, and the cause, or supposed cause, of the fire. In the city of Boston there were, during the year 1893, 1,233 fires, with a loss of $5,024,765.04. Twenty per cent. of all these fires are from unknown causes. When these unknown causes cost property owners more than $1,004,955 it is about time that some investigations were made beyond attributing these causes to spontaneous combustion, incandescent or are light wires, or to any other wires which enter a building. When an inspector cannot satisfy himself that it was from the stoves, careless use of kerosene or matches, it is a very easy thing to lay it to spontaneous combustion or the unfortunate electric light wires.

The person attributing fires to the electric light wires being crossed with some trolley or other high potential wire outside is probably not aware that every wire entering a building is thoroughly protected at its entrance by a fusible metal which will blow out at any overcharge, thus deadening every wire in the building; and, moreover, there would have to be a decided ground within the building, which is nowadays a very rare occurrence, as the

writer's investigations have proved that out of twenty-five prominent buildings in the city of Boston the insulation resistance to ground proved to average over 2,000,000 ohms. But when I say that the electric light and power wiring should not receive the blame as often as it does, I do not mean to take the responsibility off electricity, for it is through this agent that I have reason to suspect the origin of many of the "unknown" causes, so-called, on fire reports.

When electricity is allowed to roam at large and in vast quantities all along our water and gas pipes and through the ground upon which the city is built, in order to get back to the sources at which it was generated, which are the street railway power stations, it is this state of affairs which is creating a trouble, the extent and seriousness of which is only known to those few who have made it a study. These street railway power stations, operating the overhead trolley system, are constantly generating thousands of electrical horse power, sending it out by overhead trolley and feed wires to the cars which it operates, and returning it to the station by means of the water and gas pipes which lie in its course. For this reason there is a tremendous electrolytic action going on all the time. The writer has samples of gas and water pipe completely eaten through by electrolytic action in three months after having been placed in the ground near street railway returns.

Wherever this returning current flows in any quantity along a pipe there is bound to be a large fall of potential, varying in different pipes as their carrying capacity increases or diminishes. In the cellars and basements of many houses I have found quite a large difference of electrical pressure between two pipes entering within one, foot of each other, and in one instance it was a very easy matter to take a piece of hoop iron and draw an electric arc sufficient to ignite a piece of waste held near it; and by connecting these pipes together with a piece of No. 18 copper wire the current flowing through it was sufficient to heat it so that it was impossible to lay one's hand upon it. In the basement of another building within the city limits, I find a man using twenty-five amperes at eight volts pressure, or electricity enough to run small motors and incandescent lamps, as well as all the electrical bells in the entire building, by simply twisting his wires around two different water pipes which enter the building. Some time ago my attention was called to two pipes which were so close together that the vibration of an elevator engine caused them to knock together just sufficient to create an arc every time a contact was made and broken. This had been going on so that it had almost completely eaten through the gas pipe, and it is perfectly evident what would have taken place had this been allowed to go on unobserved. The gas would have been ignited by the electric spark as soon as the first small hole appeared, and disastrous results would have undoubtedly followed.

This difference of electrical pressure between water and gas pipes is now so well known that in a number of cases in the cities of Boston and Cambridge the ordinary electric bell battery is entirely discarded, and the wires from the bells connected directly to water pipes, the latter furnishing an inexhaustible supply of electricity at the proper pressure to run any number of bells or gas lighting apparatus, and also to do any quantity of mischief. I can see no reason why fires should not be attributed to this cause, when it can be proved that such a difference of electrical pressure really does exist between any two pipes entering a building in the vicinity of the trolley system of street railways.

There is only one way of eliminating this rapidly increasing danger, and that is by compelling the electric street railway companies to insulate from the ground their entire electrical circuit, and just as soon as a suit for damages is brought by the water and gas companies for systems of pipes destroyed by electrolysis, the railway companies will begin to remedy the evil, which they are more fully aware of than anyone else.

FRANCISCO, CAL.

(From A Special Correspondent).

"What would the Midwinter be without electricity!" a prominent Californian was heard to exclaim, and that is the thought, if not the expression, of all who visit the "Sunset City." The marvelous lighting effects produced on the Bonet Tower and in the electric fountain, the flashing of the great search light and the fairyland enchantment of the evening illuminations, taken as a whole, these are the things that people go to see, and talk about after they have gone.

The principal Buildings, five in number, are situated on the four sides of the Grand Court. The architecture of the Palace of Mechanical Arts, Liberal Arts, and Administration Buildings is oriental in character, while the Fine Arts Building speaks of the Nile; and the old Californian Mission appears in the Palace of Agriculture and Horticulture. All of these structures are outlined with incandescent lamps and as the Golden Gate gradually closes after the retreating form of Old Sol, streams of light begin to run here, there, everywhere, carving out of the dusk one beautiful palace after another and finally out of the centre of the Court a mass of fire climbs up into the heavens and the Bonet Tower stands, all dazzling with red, white and blue light.1

The Tower is 265 feet in height, with a base 48 feet square, a graceful structure of latticed ironwork. An elevator runs up through its centre, carrying passengers, first to a landing 90 feet up, where the inner man can be refreshed, and then still higher to a platform, 200 feet above the ground, where the eye is feasted on a grand view of San Francisco's hills, thickly covered with residences, and then beyond, to the magnificent

EXHIBIT OF THE WESTERN ELECTRIC CO.

Bay, and out to the Pacific, while just below and around lies Golden Gate Park and the Sunset City.

Every truss and brace in the tower is thickly studded with 16 c. p. incandescent lamps, to the total number of 3,213. Twelve hundred of these lamps are arranged into variable designs, which appear and disappear, increase and diminish, as if by magic. These lamps are controlled by a large rotary switch operating on the principle of the barrel in a music box, one hundred sets of cams or projections, on its surface, actuating a like number of bell cranks, at whose outer ends are clamped carbon points. As these points are lowered and raised the various circuits are closed and opened, an air jet at each contact, blowing out any damaging spark. The barrel is revolved at a regular rate by a small electric motor, while a second motor runs a small air blower. Any combination of circuits may be obtained, as the projections can be easily removed and placed in any desired relation with each other. The designs at present in operation were selected by Lieut. Hasson, Chief of Electrical Department, from twelve sets submitted by Mr. Jenness of the Western Electric Co. The number of lamps employed in these twelve sets varied all the way from five to forty thousand and that in use is a combination selected out of the lot. On the platform at the very top of the Tower, is placed the largest search light in the world, built by the General Electric Co., throwing a beam of light which is roughly estimated to be of 350,000,000 candle power. The tower was designed by Mr. Bourgeois, architect, of Chicago, and was erected by the Pacific Rolling Mills of San Francisco.

The tower incandescent system was installed by the Western 1. A Birdseye View of the Fair, with numbered references, will be found in THE ELEC. ENGR., Vol. XVI., No. 292, Dec. 6, 1893, page 495.

E. W. Goldschmidt. The exhibit of this company in the Palace of Mechanical Arts, which is in charge of Mr. C. D. Wilkinson, is worthy of note. It consists of two 150 K. W., 220 volt, 6-pole generators and two 30 K. W. generators, the latter operated by a 60 K. w. 500 volt motor. These not only furnish current for the tower, but also for the electric theatre and for the power circuit throughout the grounds. Four 50-light arc machines, of the wellknown pattern of this company, furnish arc lights for the Manufactures and Liberal Arts Building. Numerous "ring type" motors, from 2 to 15 h. p., are operated from the power circuit. Two large marble switchboards are also exhibited by this company, each having a capacity of 1,200 amperes at 250 volts and 800 arc lights.

At the east end of the court is one of the large Stieringer electric fountains which added so much to the World's Fair illuminations. This is operated by the General Electric Co., who have a large and varied display of apparatus in Mechanical Arts Building. A complete three phase power transmission plant is shown in actual operation, the power being furnished by a bi-polar motor, which is belted to a 35 K. W. generator. The voltage "steps up,' by means of transformers, from 300 to 6,000 and then down again at the other end of the line to 110, where a portion of the current is used to operate a 10 h. p. three-phase motor, which is belted to a generator having revolving brushes, for operating drills for mine work. A 10 h. p. mining locomotive is running back and forth over a short section of track. A 200 K. w. railway generator furnishes current for the cornice lighting of the various buildings and for running the tower elevator motor. A 150 K. w. Edison generator supplies the lamps in the electric fountain and the instruments is a very large and interesting one. search light on tower. The display of pumping machinery and of

A complete railway truck with G. E. 800 standard equipment and series-parallel controller is shown. Eight arc machines supply current for four hundred lamps for lighting the drives and some of the concessions. A 6,000 light alternator furnishes the current for inside incandescent lighting at night and also for a small search light, which assists in the fountain illumination. Mr. F. H. Dorr has charge of all General Electric Co. exhibits at the Fair.

Lieut. W. F. C. Hasson is Chief of the Midwinter Fair Electrical Department and to his skill and energy is due the great success of the electrical features of the Exhibition,

LITERATURE.

Progress in Flying Machines. By O. Chanute, C. E. New York. Am. Engineer and Railroad Journal. 8vo. Illus. Price, $2.50.

This is an extremely interesting book, to which Mr. Chanute's deep study of his subject gives special value. There are many who believe that while occasional flight may become possible by means comparatively simple, open to everybody, sustained aerial navigation will owe its eventual success to electricity in some form or another. In this book will be found a vast amount of useful and instructive data bearing upon such points. Not only does Mr. Chanute give us the early chronology of the art, but he discusses in full the experiments of such men as Maxim, Lilienthal, Hargraves and Langley, and handles the various theories they advance. As an engineer Mr. Chanute is able to prick many a bubble and fallacy, while his genuine enthusiasm for the subject leads him to examine carefully into the most unlikely project. A good book often does much to establish the fact that a new art has come into being, and the present volume will in time we think come to be regarded as the pillar which stood at the parting of the ways between failures of the past and the triumphs of the future. We trust that the book will have a large circulation. It is highly suggestive and touches so many fields of modern inquiry of invention that we can hardly believe any progressive scientist or engineer would care to deny himself a perusal of it.

Transmissione Elettrica del Lavoro Meccanico. By Giuseppe Sartori. Milan, 1894. Ulrico Hoepli. 411 pages, 61⁄2 x 9 inches. Price, $2.55.

THE author has given us a very clear account of the laws and principles underlying the various methods now employed in the electrical transmission of power. He treats in succession of the methods of transmission by continuous and alternating currents and illustrates their application by descriptions and a number of trace the influence of American and English electrical engineers typical power transmission plants. Throughout the work we can on the trend and method of treatment of electrical problems at the present time. We also note the adoption in Italian, as in other European languages of the term "feeder" for which there appears to be no equivalent or, at least, no such short or significant a term. The book is well illustrated and accompanied by a very comprehensive index.

THE AMERICAN INSTITUTE OF ELECTRICAL

ENGINEERS.

THE meeting of the Institute this month at Philadelphia, promises to be one of unusual interest and importance as the programme already printed shows. The Institute is just completing the first ten years of its existence and entering upon a term of even greater usefulness and activity. It has enjoyed steady prosperity for six or seven years past, and it now appears that 1893-4 will be its best year up to date. Mr. Pope, the secretary, informs us that the number of new members who have qualified this year is 160 and that before the fiscal period ends this month, it will reach 175. This is a showing that might well be called magnificent, in view of the general state of depression in all branches of electrical industry, and the fact that a great many electrical engineers have found it hard work to maintain their ground or gain a footing, The Institute will begin its second decade 800 strong, or far larger in membership than its most sanguine and devoted friends dared hope a few years ago.

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That the Institute is so progressively flourishing is the best proof that could be given of the esteem in which it is held and the desire of all the members to second the efforts put forth by successive presidents and councils to promote its dignity, influence and welfare. It is possible that a few mistakes may have been made by the management, as some of the more acute and vigorous of its critics allege, but these mistakes, if such were made, are assuredly nothing more than minor judgment from which a society or an individual can hardly ever be absolutely free. On the whole, and throughout, it is safe and true to affirm that no technical body in this country has a higher, brighter, cleaner record as to its policy and its work, than the Institute; while perhaps there is none that has been freer from "cliques" or has sustained from first to last so little deserved adverse criticism. It is only to be hoped that as the years roll by, the newer men entrusted with its destinies will be even more zealous, if possible, than their predecessors, to promote its success and increase its usefulness as the national society of the electrical engineering profession in America.

The meeting begins at 10 a. m., on May 15, and will last four days.

A CONTACT RAIL, STOrage batTERY RAILWAY. We devote considerable space this week to an illustrated description of the Johnson-Lundell electric railway system, which has been under experimental test in this city for some months past. To all appearances, it is a most important advance in the art, combining very ingeniously all the great advantages of both the closed conduit method and the storage battery car, and abolishing at one stroke all the evils of the overhead wire. Moreover, several new features are introduced in the car, which has but one motor specially geared in such a way as to obtain the benefits of series-parallel control, with an ability to govern the motion of the car entirely through the switch handle. A system so thoroughly and cleverly worked out as this seems to be, makes a strong bid for the public favor denied the trolley.

LETTERS TO THE EDITOR.

CONNECTING FIELD MAGNETS TO BUS BARS.

IN Mr. Van Nuis' article on "Connecting Field Magnets to Bus Bars" in your issue of May 2, he remarks that the method shown in my sketch (ELEC. ENGR., April 11, 1894) combines the field switch with the rheostat "in such a way as to bring the opposite poles of a circuit into dangerous proximity." Why into dangerous proximity? The poles are no nearer together than in the double-pole main switches generally used on switchboards.

When a machine is to be shut down by the arrangement shown in my sketch the lever passes off the last rheostat point before making contact with the short circuiting point, but even if contact were made with both points at once the circuit is only closed

through the entire resistance of the rheostat which is sufficient to prevent considerable flow of current.

As to the increased complication and cost of the rheostat, it consists in one extra contact point and one extra binding post. WM. A. ANTHONY. VINELAND, N. J., May 3, 1894.

PATENT NOTES.

PROF. FORBES' DYNAMO PATENTS.

ON May 1, three patents were issued to Prof. George Forbes, which are said to embody some of the principal features of the 5,000 h. p. dynamos about to be installed at Niagara, and which were discussed in Prof. Forbes' paper read before the Institution of Electrical Engineers.'

One of the patents describes very clearly the objects which had to be attained. The first object was a possibility of winding the machine to get a high E. M. F. as safely in the machine itself as in a step-up transformer. This can be done in a large machine of 5,000 h. p., where the space occupied by insulation need not bear the same proportion to the space occupied by wire as in a smaller machine and where oil circulation can be employed. It can be accomplished by having the armature stationary, especially if the shaft be vertical. The position has been taken up by Prof. Forbes that it is possible to do away with the cost and losses in a step-up transformer, that the large stationary armature is as safe to wind as is the step-up transformer, and if the difficulty of using very high electric pressures in the dynamo be shirked it must be faced in the transformer.

The next three objects were all attained by one simple expedient. These were (1) to get mechanical security having in mind the enormous centrifugal forces at a speed of 250 revolutions a minute; (2) to have a maximum of fly-wheel momentum with a minimum of weight, and (3) to prevent the magnetic pull from assisting centrifugal force to rupture the revolving part. These were all attained by the simple expedient of making the revolving fields external to the armature.

It is said that every one of the designs submitted to the Cataract Company had a separate fly-wheel which increased the weight to be supported by the hydraulic piston in the turbine beyond what it was capable of supporting. In all the designs the magnetic pull between the field poles and the armatures helped centrifugal force to break the revolving part, and in those with revolving fields the field coils were held in by pole faces held in place by bolts and keys, a source of weakness considering the high centrifugal forces.

Owing to the great diameter of the revolving part there is a maximum momentum with minimum weight, and all need for a fly-wheel is done away with. When the load is removed, and while the turbine-governor is cutting off the water, this enormous momentum prevents the machine from varying its speed unduly. Moreover, the magnetic pull between the pole pieces and armature diminishes very appreciably the tendency of the centrifugal force to break the fly-wheel; while the pole pieces and their coils are all held securely by the centrifugal force against the interior of the ring which forms at once the fly-wheel for the turbine governor, and the yoke for the field magnets. Further, the central armature being fixed can be wound for very high electric pressures.

Of the two other patents issued at the same time to Prof. Forbes one refers to the notching of the armature to hold two types of coils which overlap each other; and the other a method of enclosing the armature coils with an envelope and circulating oil through the coils, to carry off the heat and to provide for high insulation.

PERSONAL.

MR. H. NEWMAN LAWRENCE, M. I. E. E., is to lecture before the Department of Electricity of the Brooklyn Institute on May 22, on electro-therapeutic 1 subjects. which will be treated in a broadly popular way.

1. See abstract THE ELECTRICAL ENGINEER, Dec. 20, 1893, et seq.; illustrations, March 14, 1894.