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will agree with me that a longer time should be allowed to elapse before statements like these can be worth much as proofs in the argument. The English are slow to move, but when they know what the new light is, I think there will be few people who, if unhampered in their choice, will elect a foul, unwholesome, and dangerous thing like gas of any kind in preference to the electric light, with all its advantages, not the least being the ease with which it can be economised without the smallest drawback to its efficiency." Many, however, are strongly persuaded that gas companies will not suffer from electricity, and Mr. Massingham, the manager of the electric lighting works at Exeter, speaking from practical experience at Taunton, at a recent meeting in the "ever faithful city," said :— "At the former place the electric light was introduced four years ago, and, of course, the shareholders of the gas company were up in arms, thinking they would get very small dividends, but as a matter of fact a demand for a better light was created, with the result that since Taunton had been lit by electricity the gas company had sold more gas than they had ever done before in the same period. So the electric light had actually benefited them." Mr. Massingham added that he was quite sure that the unnecessary alarm which was felt in Exeter when the introduction of the light was first suggested had proved groundless; he sincerely believed that the local gas company would be benefited, because there was no more chance of the electric light doing away with the use of gas than the steam engine had of doing away with horses. At Hastings, one of the most flourishing watering places on the South Coast, the Council has decided to apply for a provisional order to supply the electric light, the action of the municipal body having doubtless been quickened by the complaints of the defective quality of the gas. Surprise is expressed in many town in the South of England that the gas companies have not taken action for the purpose of supplying the electric light; there is, however, one exception, viz., at Falmouth, whose gas company wishes to have two strings to its bow. An influential inhabitant interposes a strong objection. "If," he says, "the Town Council consents to their application for supplying electric light it will, in my opinion, have reason to regret it. Why do not the Corporation ask for borrowing powers, and ask the parishes of Falmouth, Penwerris, and the Borough of Penryn to amalgamate for the purpose of joining with the borough in order to supply electric light to the whole of the two towns, to be worked by water supplied by the Water Works Company? If, as an authority, we sanction the present application, what will the result be? The shareholders of the Falmouth Gas Company have been deriving big dividends and bonuses at the expense of the consumers. Compare the charges at Plymouth with those of Falmouth; every fair minded man must admit that the latter are very high, and can only be reduced by the public bodies of this and other places taking the matter up in order to relieve the ratepayers of some of the heavy burdens they have now to bear." The foregoing quotation is but a sample of the complaints, which are universal, as to the price and

[SEPTEMBER 13, 1889.

quality of the gas supplied, and, having regard to these, it is "passing strange " that the electric light has not made greater progress. But, notwithstanding all the opposition that the new light has to encounter, time is on the side of the improved illuminant, and when once a really good start has been made it will advance by "leaps and bounds."

VIENNA at present offers a haven of rest for some of the many ex-useful electric light patents. The St. James's Gazette says that a millionaire has just died in that fair city who had such an antipathy to darkness that he has left instructions in his will for the illumination of his last resting place. An electric light is to be kept burning in the vault for a whole year, and even the interior of the coffin is to be electrically lighted. The expenses are to be defrayed by a special bequest of 20,000 marks. This is one way, says the St. James's Gazette, of brightening the dark road to eternity; knowing some electric lights we should think not.

THE address of Prof. Flower to the British Associa tion is very intesesting reading, but it contains nothing of any interest whatever to the engineer, electrician, chemist, mathematician or physicist. It is mainly a dissertation upon the organisation and management of museums, and it will afford much food for reflection in the minds of those who are either directly or indirectly connected with these valuable institutions. Those who expected something sensational in the way of fresh theories or doctrines were doomed to disappointment, and the address will probably be voted as one of the tamest and mildest ever delivered by a President of the British Association for the Advancement of Science. It is, however, eminently respectable, and not calculated to upset preconceived notions, or to painfully affect a sensitive nature such as has been the case on more than one previous occasion.

We

Mr. W. D. SANDWELL has written to us respecting the letter of Mr. Willis, which appeared in our last issue. He also sends two specifications of his patents, "by which you will see that they are not anticipated by the sketches in your paper of April 13th, 1888." have examined these blue books, and find that in one there is claimed :-" The combination with a tramcar or other vehicle or apparatus adapted to be driven by electricity of an electric motor mounted on the said car and a set of accumulators from which the electricity for operating the said motor is derived, the said accumulators being located in a truck or tender adapted to be connected with and disconnected from the tramcar, or the like, as set forth." In the other we find that the inventor does not claim placing two armatures on the same axle, one only of such armatures being operative at the same time; but he claims :-" In an electric motor the employment of two armatures in connection with one set of field magnets, the said armatures and field magnets being arranged in such a manner that they can be moved relatively to each other for enabling either armature to work in the magnetic field for the purposes specified." In how much this last claim trenches upon the patent of Mr. Jarman, or in what the value of the first consists, we leave others to decide. Mr. Sandwell very kindly volunteers to supply us with an epitome of his failures and their

REVIEW

causes at Holloway, but we really do not think that it is necessary. We have previously expressed an opinion upon his apparatus, and so far we see no good reason for modifying our remarks.

THE inauguration of the Bradford electric light installation is to take place about the middle of next month. Even at the present moment the arrangements for the supply of electricity are practically complete, and it would be possible to lay on the current at once if it were considered urgently necessary, but as several members of the Lighting Committee are absent, and the evenings will soon begin to lengthen, a postponement has been deemed advisable, a course which will allow time for engaging a staff of employés.

THE Sunderland Gas Company probably supplies gas at a cheaper rate than any other company in the kingdom-namely, at 1s. 6d. per thousand to large consumers. This very moderate price is doubtless the reason why the chairman of the company (Mr. E. C. Robson), at the annual meeting last week, made such remarkable statements, which showed great ignorance. No large town, he said, was lighted by electricity at a profit; but there are, as many persons are aware, several towns in the United Kingdom where public electric lighting has been made a financial success. Then, again, he had never heard of electricity being supplied at a cheaper price than that which corresponds to 1,000 feet of gas at 6s. 8d. This price is, of course, equal to the Board of Trade unit at 8d., which is the maximum rate permitted to be charged by that Department. We wonder whether the chairman was furnished with a copy of a price list issued a short time ago by a certain provincial electric lighting company offering to supply current at 44d. per unit, which is equivalent to gas at 3s. 9d. per thousand. Other companies are also about to supply current, or are already doing so, at less than the 8d. maximum.

THE Nottingham papers state that an important invention has been made by a fellow townsman of the "lambs." The primary object of the patent is to afford means whereby the driver of a locomotive may tell exactly how the signals are at particular points on the railway over which his train is proceeding. A further important use of the apparatus is in the direction of registering distances between trains and establishing telephonic communication. For the experiments on Saturday last, as in the preceding week, a mile and a quarter of the suburban line, running from Sherwood Station towards Daybrook, had been selected. Parallel with the permanent way, a slight wooden rail had been placed, upon the zinc-covered surface of which a wire was laid. By means of a brush attached to the footplate of the engine electric communication was established in turns between the wire and two dials placed on the weatherboard of the locomotive. One of the dials was in the form of a miniature semaphore signal, the other being similar in appearance to a steam gauge dial, and capable of registering distances from a quarter of a mile up to nine miles. In all respects the apparatus worked admirably. An operator was stationed at each end of the wire, and when acting upon a previously arranged code the signals were put on or taken off, the fact was at once indicated by the dropping or raising of the arm of the small semaphore signal on the

engine. This was effected with the greatest readiness, whether the locomotive was stationary or in motion. By means of the second dial the distance between various points was also indicated to a nicety. The telephonic possibilities of the invention were not tested on Saturday, but the experiments in the previous week amply demonstrated the possibility with Mr. Andrews's apparatus of a driver, guard, or passenger in one train communicating with a person in another train. Acting on a similar plan, it, whilst in motion, is also regarded as being possible for a passenger to communicate from a train to a telegraphic office en route, and give instructions for sending a message. The use of the signalling apparatus would probably prove of the greatest value in foggy weather, when the ordinary signals cannot be seen. At any point from 200 to 400 yards outside the distance signal, the driver would be able to tell at once in what position the particular signal might be, and whether he was at liberty to proceed. We hope shortly to hear further particulars of this invention, although if the inventor can ever succeed in inducing railway companies to adopt it, we shall consider that his neatest feat, for no matter how good and useful a purpose an invention may effect, it is more or less the labour of a lifetime to get it adopted on English railways.

IN an evening contemporary (the St. James's Gazette of last Friday) the following paragraph appears under the heading of "The Greatest Depths of the Ocean" :"The greatest known depth of the sea is in the South Atlantic Ocean, midway between the Island of Tristan d'Acunha and the mouth of the Rio de la Plata. The bottom was there reached at a depth of 40,236 feet, or 83 miles, exceeding by more than 17,000 feet the height of Mount Everest, the loftiest mountain in the world. In the North Atlantic Ocean, south of Newfoundland, soundings have been made to a depth of 4,580 fathoms, or 27,480 feet, while depths equalling 34,000 feet, or 61⁄2 miles, are reported south of the Bermuda Islands. The average depths of the Pacific Ocean, between Japan and California, is a little over 2,000 fathoms; between Chili and the Sandwich Islands, 2,500 fathoms; and between Chili and New Zealand, 1,500 fathoms. The average depths of all the oceans is from 2,000 to 2,500 fathoms." This information is incorrect in every particular, and might give rise to misgivings in the minds of those interested in submarine cables, as such loose and careless statements frequently do, when backed up with an appearance of authority. The greatest depth between the Island of Tristan d'Acunha and the mouth of the Rio de la Plata is not 6,706 fathoms, but 2,900 fathoms. In the North Atlantic, south of Newfoundland, the greatest depth is 3,327 fathoms, not 4,580 fathoms. To the south of Bermuda, the greatest depth is 3,825 fathoms, not 5,666 fathoms. The remainder of the information given in the paragraph is also incorrect. We believe that the deepest soundings yet taken in any waters are the following: 4,655 fathoms (or 5 statute miles), found off the Kurile Islands by Captain Belknap, of the U.S.S. Tuscorora, who also found 4,643 fathoms off the Coast of Japan. Next in depth there comes a sounding of 4,561 fathoms, taken about 60 miles north of Porto Rico, in the West Indies, by Captain Bartlett, U.S.N. Following these, a depth of 4,475 fathoms was found by the Challenger in the Pacific to the east of the Philippine Islands; and recently, in the South Pacific, about 250 miles to the south of the Friendly Islands, a depth of 4,430 fathoms was met with by Captain Aldrich, of H.M.S. Egeria.

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NOTES FROM SWEDEN.

THERE is every probability of a central electrical station being soon established in Stockholm by the city, the gas board claiming to be able to solve this question more satisfactorily to the public than a number of small speculators, whilst the economical result may be gauged by the large profit yielded by the gas works. However, as the plans hitherto submitted for such a central station have been wholly incomplete and useless, the gas board proposes that an international competition for the works be invited, with prizes for the best plans and suggestions, and that to this end a sum of 15,000 kr. be provisionally granted the board for the purpose of preparing by an undoubtedly qualified expert the programme for such a competition. The proposal of the board will no doubt soon come before the municipal council.

The gas board has furnished some interesting particulars respecting the use of gas motors in Stockholm. Thus, at the end of 1884, when the gas for such engines was lowered to 15 öre (2d.) per cubic metre, there were 21 equal to 52 horse-power in use, whilst at the end of last year, the number had increased to 57, totalling 140 horse-power. The consumption of gas by these cost £800. However, the use of gas motors has not nearly increased so greatly as in Germany, the proportion per 1,000 inhabitants in the Swedish capital being 0-6 horse-power, whilst in Germany it ranges from 0.9 to 2.4 H.P. per 1,000. It is therefore demanded that the price be lowered.

The report of the Electrical Lighting Company, of Stockholm, for last year, shows great progress, 36 dynamos and 4,139 lamps having been delivered, as against 20 and 2,658 respectively in 1887. Since the formation of the company, in 1883, 121 dynamos have been delivered, of 1,426 horse-power, which are now working 13,100 glow and 15 arc lamps. The profit last year on the capital was 7 per cent., but the whole of it is to be employed in enlarging the business.

The introduction of central municipal stations has been decided upon by the corporation of three more cities, viz., Marstrand, Arboga, and Ostersund, with about 1,000 lights in each.

The Swedish Patent Office has issued some interesting statistics, from which it appears that during the last three years 18 patents were taken out by Swedes upon illuminating inventions, 3 only, however, referring to the electric lighting, the rest to the perfection of gas. This is explained by the circumstance that the attention of Swedish electrical engineers just now is wholly concentrated upon supplying the demand for electricity for every purpose. As regards motors, for the same reason, 26 patents were granted for gas, steam, and water motors, but not a single one for electrical ones. However, 7 patents granted referred to the telegraph and telephone service.

A new telephone tax has come into force in Sweden, whereby the charge on the State telephones has been fixed at 30 öre (4d.) for three minutes' conversation when the distance is under 100 miles, and 50 öre (64d.) for distances above, with 10 öre (14d.) for every extra minute in both cases. However, if the telephone be bespoken, each conversation must not last more than five minutes. The reason of this curtailment of time is that very few conversations occupy the time now allowed, viz., five minutes. This has also been the experience in various other Continental countries, as for instance Switzerland, where the time is now also only three minutes.

A novel but useful application has been made of the telephone in Stockholm, most of the passenger coasting steamers having been fitted with apparatus which can be connected with a station on the quays when in port, whereby communication with the whole city and even most of the country is maintained-a great advantage obviously both to the public and the owners of the

port of the Stockholm Bell Telephone Com1888 shows 1,755 subscribers, against 1,700

[SEPTEMBER 13, 1889.

in 1887. 66 persons were employed against 73 in 1887. The earnings were £8,000, and the net profit £2,500, or a little more than in 1887. The report of the Stockholm General Company shows 4,556 subscribers, with 400 in other towns. The company possesses 6,193 kilometres of telephone lines in the capital and 2,400 in the country. In 1888, 8,768,000 messages were transmitted, or 29,260 a day. The earnings were £3,500, and a dividend of 8 per cent. is paid.

A local telephone company has been constituted in the province of Osterdalen, in Dalcarlia.

From the foreign report of the Swedish telegraph service last year we learn that 750,885 messages were received and transmitted, 264,318 being sent out and 305,544 received, whilst 181,023 were in transit from England and France, to Russia and Siberia. The increase upon 1887 was 15.4 per cent. As usual, the greatest exchange was with this country, viz., one-fourth of all messages or 152,161, against 126,530 in 1887. Germany comes next with 131,525. The increase with this country in 1888 is 20 per cent., whilst 19 per cent. more messages were received from than dispatched to this country.

ON CHENOWETH'S ELECTRIC CONDUITS. [Report of the Committee on Science and the Arts.]

Hall of the Franklin Institute, Philadelphia, April 29th, 1889. The Sub-Committee of the Committee on Science and the Arts, constituted by the Franklin Institute of the State of Pennsylvania, to whom was referred for examination,

THE CHENOWETH ELECTRIC CONDUITS,

Report that The invention belongs to that class of conduits in which the material of the conduit is packed while in a plastic condition, around one or more cylindrical cores, which are removed after the plastic material has hardened. The essential part of the invention is the nature of this removable core, which enables it to be withdrawn in long lengths. This core consists of a ribbon of galvanised iron, 1 inch wide, and of a thickness equal to No. 27 gauge, which is wound spirally, forming a tube. This spiral tube is rendered rigid, either by being wound around a split wooden core, or by having paper glued around the outside. The plastic material is packed around these tubes, and after it has set the tube is removed by pulling out this spiral band. When paper has been used to hold the spiral together it readily tears, allowing the band to be removed. When wooden cores have been used, they are first withdrawn, after which the spiral band is readily pulled out.

Among the details of the system are the following:-When paper is used to unite the spiral into a rigid tube, the ribbon is first wound spirally on a mandrel, then covered with paper, which is glued fast to the outside of this spiral, and the whole covered with a water-proof varnish. The mandrel is then removed, leaving a thin tube, which appears to be quite rigid and capable of withstanding the pressure due to the packing of the plastic cement of the conduit around it. These are laid in lengths and held in position while the cement for the conduit is packed around them. The ends of the one spiral ribbon are fastened to the beginning of the next by a swivel joint. After a few days, when the cement has hardened, the spiral ribbon is pulled out at one of the manholes, tearing and thus removing the paper around it. It is claimed that long lengths of this spiral tube can be thus removed.

When this spiral tube is wound over a wooden core, this core is made in two semi-cylindrical halves, separated by a thin iron strip. The outside is painted with a mixture of clay, powdered soapstone and water. These are laid in lengths of 14 to 20 feet, and after the cement is packed around them the wooden cores are withdrawn, after pulling out the strip of iron separa

Franklin Institute Journal.

SEPTEMBER 13, 1889.)

ELECTRICAL REVIEW.

ting them. This leaves the spiral tube, which remains until the cement has hardened, and is then withdrawn in long lengths.

The inventor claims that continuous lengths of 400 feet of spiral tube can thus be withdrawn. For removing this ribbon the inventor states that he has a peculiarly constructed reel, by means of which the ribbon can be pulled out, wound up, and untwisted in one operation.

For the material used for the conduits the inventor prefers a mixture of one part of hydraulic cement and two parts of sand. The costs are given by the inventor as follows :

"The cost of constructing ducts by this method is narrowed down to the winding of the ribbon on the mandrel, the labour of removing the mandrels in the trench, of removing the ribbon from the duct and rewinding the ribbon on the bobbins. And as each part of the core is preserved and used an indefinite number of times, the cost of the core is charged to the cost of the plant. The winding of the ribbon is done on the spot as fast as wanted. The cost of drawing out the ribbon and rewinding on bobbins, using an ingenious device that removes all twists, is about one mill per foot. A duct, 4 inches in diameter, made of concrete, in the proportion of one of cement to two of sand, can be made for 6 cents per foot, including entire cost, exclusive of excavation, manholes, and cpenings."

The inventor claims that the advantages of the paper-covered tube is convenience, the cost being about the same.

The inventor gives the following comparative costs of materials for three forms of conduits. The estimate is for a conduit of four ducts, 4 inches in diameter, 1 foot long. For creosoted wood, 6 cents per foot per duct; for iron pipe, encased in concrete, 18 cents per foot per duct; for his conduit, 3 cents per foot per duct. This does not include excavation, which is about the same for all. It does not include the cost of handling his removable core.

Your committee have examined samples of these removable cores and portions of conduits made in this way, and are of the opinion that the invention is simple, ingenious, effective, and inexpensive. Furthermore, an invention of an efficient removable core enables monolithic conduits to be made of hydraulic cement, whose properties are already well known. Unlike creosoted wood, it contains no substances which are likely to attack chemically the insulation or the lead armour of cables, and, unlike iron, it does not corrode. The results, therefore, which can be accomplished by means of this removable core are unquestionably of value.

Your committee recommend the award of the John Scott Legacy Premium and Medal to Alexander Crawford Chenoweth for his improved method of laying continuous electrical conduits.

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was the very lowest minimum which could be supplied. The usual power was 16 candles. Mr. H. N. Jenkins directed attention to the electric light in the square by the Brush Electrical Engineering Company, and said he thought that the permission given to erect standards should now be withdrawn. The permission was given for four or five days, and to erect four standards; there were now five standards, and if the company were allowed to remain it might be the thin edge of the wedge to make themselves the only company in Bournemouth. He therefore moved that the permission be withdrawn, which Mr. George seconded. Mr. Hankinson, in opposing, did not see why the Commissioners should be afraid of the company calling themselves the only company in Bournemouth. As a matter of fact, they were at present the only company in existence in the town, and he certainly did not see why they should be treated as curtly as proposed by Mr. Jenkins. The light in the square was a great improvement and attraction, and as the company were exhibiting it at their own expense he (Mr. Hankinson) did not see why the Commissioners should prevent them from continuing it. Mr. Sworn remarked that every body seemed much pleased with the light. At the request of Mr. H. F. N. Jenkins the minute authorising the erection of standards was read, from which it appeared that permission was given to the company to erect standards for the light on regatta day" and for the following week or ten days." Mr. H. W. Jenkins did not think the Commissioners should be in such a hurry over the matter; it would be quite time enough to take action at the next meeting if any nuisance was caused. It was very possible the promoters themselves would discontinue the lighting before then. Mr. H. N. Jenkins withdrew his resolution, and the matter dropped.

ELECTRIC LIGHTING AT BRIGHTON.

MR. G. R. ANDREWS, the Brighton Borough Engineer, has made a report to the County Council of that borough upon the electric light installation at the Royal Pavilion, dome, free library, museum, and other buildings in connection therewith, and upon the necessity of making certain alterations before the season commences, with the view of reducing the cost of lighting and guarding against accident. The present installation consists of one 40 H.P. Robey engine and one 20 H.P. ditto (not in use), two Siemens's dynamos, each capable of providing 400 16-C.P. incandescent lights, equal to a total of 800 16-C.P. incandescent lights. 811 16-C.P. incandescent lights are now being used when in full work, or eleven more than the maximum quantity that the machinery provides for, so that if there is the slightest breakdown in any part of the machinery there is a total failure in the electric lighting of these important buildings.

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The Borough Engineer makes the following recommendations and suggestions:-1. To make the engine and dynamo shed larger, so as to be able to get at the dynamo properly. The bed and holding down bolts of No. 2 dynamo are now so defective, and the vibration is so great when it is in full work, that it is positively dangerous and very injurious to the plant. 2. To move the dynamo to the place indicated on the plan and connect it up with the intermediate shafting, so that we could use either the 40 or the 20 H.P. engine. 3. To provide 60 E.P.S. 23 L accumulators secondary batteries. By that means we shall always have a reserve in case of a breakdown; also, should there be only a small quantity of light required (say only one or two of the rooms, such as the free library or the banqueting room) we need not use the large 40 H.P. engine but the small one (thereby effecting a great saving in coal and cost of the electric lighting), or, in fact, without the necessity of running the engines at all in the case of a breakdown. By this means the Free Library could be always lighted by the electric light, which is a very desirable thing to

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do, in order to preserve the binding of the books. The present system is just as reasonable in its working as if a gas company attempted to supply gas without gas holders. I have estimated the cost to do this work as follows-Alteration of shed for engine and dynamo, including bed with holding-down bolts, and to provide space for accumulators or secondary batteries, £60; cost of accumulators, £300; alteration of machinery, belts, &c., £180-total, £544.

This work might be done so as not to interfere with either the lighting of the Dome or the Pavilion separately; but it could not be managed so as to keep the whole installation going at once, without having a new dynamo, which would cost about £300, and, I think, be quite unnecessary. The proposed accumulators would be the greatest addition to the present plant, not only for safety and economy, but would allow of more lamps being added where necessary, and always ensure the electric light for the Lending Library. It must be distinctly understood that I do not recommend that any extra lighting should be done unless the accumulators are provided, and the alterations carried out. I think if this work is done, you will have one of the most complete electric light installations in this part of the country.

ELECTRIC LIGHTING IN ASIA.

As far as we are able to judge at the present moment there appears to be an excellent field open to electrical engineers in Asia, and this is now quite ripe for development. Only a short time ago a company was formed in China for the purpose of supplying electricity, chiefly for lighting purposes, and, if we remember rightly, a similar company has been constituted in Japan. In the former country the Emperor is said to be greatly in favour of the employment of electricity, and his Majesty has already adopted it as an illuminant in one of his palaces in preference to the lighting system generally in vogue in that empire. The Shah of Persia, too, is greatly interested in electric lighting, as was shown on the occasion of his recent visit to this country, and we believe his Majesty is about to have one of his palaces electrically lighted. In India the use of the electric light is making slow, but steady progress. Some of the petty monarchs have already adopted it, and others are considering the matter.

A short time ago the Harbour Trusts of Kurachi and Rangoon decided in favour of the use of electricity, and now the Calcutta Port Commissioners have followed their example. A proposal was recently brought forward by Messrs. Octavius Steel & Co., of Calcutta, who are the Indian agents for Messrs. R. E. Crompton and Co., of London (the latter being the proposed lighting company), to light the jetties, the Hooghly pontoon bridge and wharves by means of electricity. The Commissioners duly considered the proposal and, notwithstanding the fact that the change from gas to electric lighting will cause an additional expenditure of £200 per annum, they have resolved to adopt electricity as an illuminant. The reasons which have led the Commissioners to substitute electricity for gas are its superiority in illuminating power and immunity from the risk of fire for warehouse lighting, and they have granted a site at Pathoreah Ghaut for the erection of the engine and boiler house. The company is to furnish 42 2,000-C.P. arc lamps, which will be distributed as follows:-On the floating bridge, 10 lamps, each placed 100 yards apart; on the wharves from bridge to Chitpore, 20 lamps at intervals of 175 yards; and on the jetties and lower wharf to Baboo Ghaut, 12 lights, each being 135 yards from one another. The average number of hours when light will be supplied will be nine, and the price will be at the rate of two annas (2 d.) per lamp hour. The cost of lighting the same area at present by gas is about £1,530, whilst for elect lumination the expense will be nearly £1,730; unt of light to be furnished by the arc cording to the company's estimate, be

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[SEPTEMBER 13, 1889.

nearly forty times that now supplied for illuminating the same area by gas. One of the chief advantages of the substitution of gas by electricity is that vessels will in future be able to discharge or load cargoes at night time, and for this purpose the company propose to put up connection boxes within and outside the jetty sheds, and in and on these will be placed movable arc lamps. At present, the unloading and taking in of cargoes at night time is only carried on under difficulties in consequence of the impossibility of gaslight being made suitable to all circumstances. For the offices glow lamps will be employed, and movable arc lamps will be placed on the vessels lying along the jetties and wharves. Messrs. Steel & Co. have proposed to the Public Ways Department of Bengal that they should light up the Calcutta maidans by electricity, but their offer has been declined.

Messrs. Crompton & Co. are, however, not going to carry everything before them, as there is another competitor in the same field, namely, the Anglo-American Brush Corporation. Some time ago the latter sent out Mr. R. P. Sellon to the East, and that gentleman has been endeavouring to secure business. He has visited, among other towns, those of Singapore and Penang, and is now on his way to Bangkok in Siam, where the king has given an order for the electric lighting of his palace on a large scale. Several of the Siamese princes and nobles have also decided to adopt the electric light, and the Brush Corporation's representative is to superintend the erection of the installations. The opposition to the employment of electricity in Asia does not appear to be so strong as that which obtains in Europe, and the only conclusion we can arrive at in the matter is that electrical engineers should be able to do a very profitable trade in the East, and for that purpose they should at once devote attention to the subject.

MAGNETIC LEAKAGE IN DYNAMOS.*

By Prof. H. S. CARHART.

IT is well known that certain forms of field magnets or their attachments favour leakage of lines of force more than others. The exact amount of such leakage I have determined in two cases, due in one to projecting steel and iron studs, and in the other to the iron bedplate. The two machines experimented on are of the Mather and Edison type respectively. The former is a small dynamo of from 400 to 500 watts capacity, and was built by a student in the physical laboratory; the latter is a No. 2 Edison machine of 5,000 watts capacity.

The field magnet of the small machine was cast in one piece, and the opening between the poles was bored out to a diameter of about 3 inches. The leakage was due to four steel studs, at first used to support the brass yokes, forming bearings for the armature shaft, and to four small iron bolts by which the field magnet was attached to the wood base.

The steel studs were screwed into holes tapped out on the side of the pole pieces. Those on the pulley side were 3 inches long, and those on the commutator side 5 inches. Each pair was 4 inches apart. Their smallest diameter was inch, except the outer threaded end, which was slightly smaller. The bolts in the base were a little over 3 inches apart, 2 inches long, and were made of -inch wrought iron.

These studs were all replaced with brass and the gain was determined by running the machine without a load, the voltmeter of 7,000 ohms resistance being connected across the terminals to measure potential difference. Two determinations were made: first, with the machine as a self exciting shunt dynamo ; and, second, when separately excited by a storage battery of 31 cells, giving 62 volts at the time. The following table exhibits the results:

* Western Electrician.

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