THE

ELECTRICAL ENGINEER.

Published every Friday.

CARLOW.

The recent election at Carlow has made prominent at the present moment a town which seems destined to become still more prominent, being the first Irish town to recognise and act upon the conclusion that

advantage be utilised to provide light. The ordinary Englishman, used to the high pressure of business life, can hardly realise the exact position of such towns as Carlow in the ranks of progressive towns. To him, accustomed as he is to noise and bustle, town in the midst of a purely agricultural country the quietude of a prosperous, comfortable county town in the midst of a purely agricultural country is characteristic of Rip van Winkleism rather than of progress. But, on the other hand, those who live in remoter districts claim to recognise the go-aheadness of such places as Carlow. From whatever standpoint one views the situation, the fact remains that Carlow, for good or for ill, has taken a step which other places have talked about, and done, when the talk has ended, absolutely nothing. Situated some 56 miles south of Dublin, at the junction of the Burren with the Barrow, a considerable amount of water power is available. In years gone by, before Russia, America, and remoter parts of the earth supplied us with corn and flour, huge mills were actuated by the waters of the Barrow, and many another Irish stream. Now the mills are not worked. More modern milling appliances, added to the action of the Corn Laws, have driven the industry into other quarters. At Milford, some five miles from Carlow, stands one of these some time silent mills, its huge waterwheel inactive, and its gearing rusting away. The happy thought of using the waste power came to willing ears, and the result has been to install in a portion of the old mill, a dynamo-room, the machinery in which is at present driven by the old mill wheel, but which will soon be driven by turbines. With a little care we should imagine some three hundred horse-power can be obtained from the Barrow at this point, and two-thirds of that power would suffice to light every nook and corner of Carlow. The matter of the town lighting had long been a sore point. The Commissioners and the gas company did not quite agree, and latterly the town was lighted with oil-when the question was put to Mr. J. E. H. Gordon, who grasped the situation, made his proposal to the Commissioners, which was accepted, and within a few months of such agreement the work has been so far completed that the town lighting is regularly carried out. The formal inauguration of the lighting was, as is usual in such cases, made the pretext for a convivial meeting and dinner at the Town Hall on Monday last. Mr. Hammond, the newlyelected member of Parliament for Carlow, who has for 12 years been chairman of the Town Commissioners, delayed taking his seat in the House of Commons in order to be present at the inaugural banquet. This action tells its own tale as to the interest taken in the lighting. Deputations from Derry, Kilkenny, Portadown, and other places were also present to

inspect the works and the results at Carlow, and from what we could gather it is pretty certain that a number of towns will follow the lead given to them. It seems to us, then, that a good meed of praise should be given to everyone connected with this lighting. Certainly Waterford, Belfast, and other places in Ireland have not been behindhand in introducing the light, but here we have an inland town of town of only some six thousands of population, with no factories, initiating the use of its natural sources of power to give light; and undoubtedly throughout the length and breadth of Ireland this attempt will be closely watched, and wherever water power is running to waste, sooner or later it will be utilised. It is not our intention to enter into details of the lighting here-that must be reserved for another issue-but we may say briefly the current is generated at 2,500 volts pressure, carried by overhead wires to the town five miles away, and transformed down to 50 volts. The transformed current will, when the work is finished, feed a network of low-pressure mains, from which the arc lamps lighting the streets and the incandescent lighting the interiors of the houses will be fed. It is but just to say the price of gas in Ireland, averaging six or seven shillings per 1,000 cubic feet, makes the introduction of the electric light less difficult than it might otherwise be. There is some probability of being able to compete in price, and the other advantages of electricity should bring it well to the front. There is one question which might be strongly insisted upon by those interested in the welfare and development of industrial Ireland. The example of Carlow must lead to the examination of the possibility of using this waste water power in various industries by the use of electric transmission and of motors. Coal is comparatively dear in many parts of Ireland, while water power is abundant. Surely some means may be devised of placing this hitherto waste power in the hands of users in the quantities they desire.

PROVISIONAL ORDERS.

According to the Board of Trade report just issued, 70 applications were made during the year for provisional orders. Of this number 37 were made by local authorities, and 33 by companies or individuals. Twelve of the orders relate to London. Out of the 70 applications, 59 orders have been secured. The Board of Trade seems to follow an almost hard-and-fast rule, granting without demur an order to the local authority, and refusing an order unless backed with the consent of the local authority. At any rate, only one order so opposed has been granted-in respect of a part of the parish of St. Luke, Chelsea, to the New Cadogan and Belgrave Company. Strictly speaking, however, this opposition was not to the company's application, but to clauses inserted at the instigation of the London County Council. The appendix to the report is somewhat interesting. The boom of the early eighties is still remembered, and

the passing of the 1882 Bill led to a rush for orders in 1883. In that year 69 orders were granted, and of these all but 13 have been worked. Several of the 13 have really proceeded with the work-the most prominent being St. Pancras and Bradfordbut others have made no movement, or so little as to be unworthy the name of work. No licenses have been applied for during the past year; the two referred to in the preceding report-viz., Chelmsford and Bath-were duly granted, and, as our readers know, both these towns are lighted. Besides these, a total of 11 licenses have been granted which have not in some way been repealed. Between 1883 and 1889 only two orders remain unrevoked, while during 1889-1890, out of 86 orders granted only two have been revoked, so that at the present time 156 orders are running, in addition to 13 licenses.

CORRESPONDENCE.

"One man s word is no man's word,
Justice needs that both be heard."

TOWNLEY'S DUPLEX ALARM.

description of Townley's duplex alarm, I should be SIR, Having seen in your issue of to-day's date a greatly obliged if you could allow me space in your columns to state that as far back as March, 1886, I designed, and have used ever since, a practically similar alarm, clock, battery, and, of course, an ordinary form bell, combination (mounted on a neat carved bracket) comprising with the improvement of mercury cups to receive clock legs, and also, by turning a small knob, in the event of a breakdown, the electrical clock contacts were thrown out of gear and the ordinary mechanical alarm substituted. I merely wish to show that there is no novelty attached to Townley's alarm.-Yours, etc., A. MCMEEKIN. Norwood, S.E., July 10, 1891.

SIR, We notice in your current number a description of invented by Mr. J. Townley. We do not know when this a new form of electric trembling bell, said to have been gentleman may have invented his bell, but we beg to inform you that our Mr. W. R. Wynne patented a bell on been manufacturing and supplying these bells for some this principle in 1885 (patent No. 7,373), and that we have time. Our patent bell has fewer working parts than the one illustrated by you, and, as we believe, is a far more practicable and reliable article.-Yours, etc.,

BARNETT, WYNNE, AND BARNARD. Newcastle-on-Tyne, July 10, 1891.

MAGNETIC BONE SEPARATOR.

Amongst the machines shown at the recent meeting of the Royal Agricultural Society at Doncaster, referred to in our notice of the show, and entered as a new implement, was the magnetic separator, which we now illustrate. This machine is intended to remove bolts, nuts, nails, horseshoes, etc., from bones, oil cake, or minerals, before they are passed into disintegrating machines, as the presence of these foreign bodies is very detrimental to the machines. The chief difficulties that had to be overcome in designing this machine were the large size and irregular shapes of the material to be treated; the fact also that the iron, partithat merely passing the substance once over or on to a magnet cularly in bones, is frequently entangled in the bones, so was not found sufficient to ensure the absolutely certain removal of the foreign substance. These points have been satisfactorily overcome by the use of a hollow truncated cone, with 10 internal magnets, of alternately opposite polarity. The cone revolves on outside runners, driven by friction only, which is found ample for the purpose.

demagnetised, and the iron is detached. This process is carried out by a commutating ring on the back of the machine, and the arrangement is such that each coil has one end permanently connected to one pole of the dynamo, and the other ends are in turn connected during one half a revolution to the other pole. Thus the magnets receive current in parallel. Before cutting a coil out of circuit, it is short-circuited through a resistance, and by this means no sparking of any consequence occurs.

The machine has proved itself a very practical success, and the value of the repeated revolutions over the magnets have been demonstrated by repeated trials. The power required to excite the magnets is about 600 watts for the largest size, capable of dealing with four tons of bones per hour.

The machine was exhibited by the Hardy Patent Pick Company, of Sheffield, makers of the Devil disintegrator, and was manufactured by W. T. Goolden and Co., under the joint patent of Messrs. D. and C. Atkinson and G. W. Elliott.

MILLING MACHINES.

The Britannia Company, of Colchester, recently issued a book upon "Screw-cutting and Milling Machines," which very completely went into the theory and practice of screw cutting of all kinds. Many new types of milling machines were therein illustrated, and we give on opposite page two of the most modern and improved machines, which will not fail to be of interest to electrical engineers.

EXPERIMENTS WITH ALTERNATE CURRENTS OF VERY HIGH FREQUENCY AND THEIR APPLICATION TO METHODS OF ARTIFICIAL ILLUMINATION.*

BY NIKOLA TESLA.

There is no subject more captivating, more worthy of study, than nature. To understand this great mechanism, to discover the forces which are active, and the laws which govern them, is the highest aim of the intellect of man.

Nature has stored up in the universe infinite energy. The eternal recipient and transmitter of this infinite energy is the ether. The recognition of the existence of ether, and of the functions it performs, is one of the most impor tant results of modern scientific research. The mere abandoning of the idea of action at a distance, the assumption of a medium prevading all space and connecting all gross matter, has freed the minds of thinkers of an ever present doubt, and by opening a new horizon-new and unforeseen possibilities has given fresh interest to phenomena with which we are familiar of old It has been a great step towards the understanding of the forces of nature and their multifold manifestations to our senses. It has been for the enlightened student of physics what the understanding of the mechanism of the firearm or of the steam engine was for the barbarian. Phenomena upon which we used to look as wonders baffling explanation we now see in a different light. The spark of an induction coil, the glow of an incandescent lamp, the manifestations of the mechanical forces of currents and magnets, are no longer beyond our grasp. Instead of the incomprehensible, as before, their observation suggests now in our minds a simple mechanism, and although as to its precise nature all is still conjecture, yet we know that the truth cannot be much longer hidden, and instinctively we feel that the understanding is dawning upon us. We still admire these beautiful phenomena, these strange forces, but we are helpless no longer; we can, in a certain measure, explain them, account for them, and we are hopeful of finally succeeding in unravelling the mystery

which surrounds them.

In how far we can understand the world around us is the ultimate thought of every student of nature. The coarseness of our senses prevents us from recognising the ulterior construction of matter, and astronomy, this grandest and most

* Lecture delivered before the American Institute of Electrical Engineers at Columbia College, New York, May 20.

positive of natural sciences, can only teach us something that happens, as it were, in our immediate neighbourhood; of the remoter portions of the boundless universe, with its numberless stars and suns, we know nothing. But far beyond the limit of perception of our senses the spirit still can guide us, and so we may hope that even these unknown worlds-infinitely small and great--may in a measure become known to us. Still, even if this knowledge should reach us, the searching mind will find a barrier, perhaps for ever unsurpassable, to the true recognition of that which seems to be, the mere appearance of which is the only and slender basis of all our philosophy.

soon

Of all the forms of nature's immeasurable, all-pervading energy, which, ever and ever changing and moving, like a soul animates the inert universe, those of electricity and magnetism are perhaps the most fascinating. The effects of gravitation, of heat and light we observe daily, and we get accustomed to them, and soon they lose for us the character of the marvellous and wonderful; but electricity and magnetism, with their singular relationship, with their seemingly dual character, unique among the forces in nature, with their phenomena of attractions, repulsions and rotations, strange manifestations of mysterious agents, stimulate and excite the mind to thought and research. What is electricity ? and What is magnetism? These questions have been asked again and again. The most able intellects have ceaselessly wrestled with the problem; still the question has not as yet been fully answered. But while we cannot even to-day state what these singular forces are, yet we have made good headway towards the solution of the problem. We are now confident that electric and magnetic phenomena are attributable to ether, and we are perhaps justified in saying that the effects of static electricity are effects of ether under strain, and those of dynamic electricity and electromagetism effects of ether in motion. But this still leaves the question, as to what electricity and magnetism are, unanswered.

First, we naturally enquire, What is electricity, and is there such a thing as electricity? In interpreting electric phenomena, we may speak of electricity or of an electric condition, state or effect. If we speak of electric effects, we must distinguish two such effects, opposite in character and neutralising each other, as observation shows that two such opposite effects exist. This is unavoidable, for in a medium of the properties of ether we cannot possibly exert a strain, or produce a displacement or motion of any kind, without causing in the surrounding medium an equivalent and opposite effect. But if we speak of elec tricity, meaning a thing, we must, I think, abandon the idea of two electricities, as the existence of two such things is highly improbable. For how can we imagine that there should be two things, equivalent in amount, alike in their properties, but of opposite character, both clinging to matter, both attracting and completely neutralising each other? Such an assumption, though suggested by many phenomena, though most convenient for explaining them, has little to commend it. If there is such a thing as electricity, there can be only one such thing, and, excess and want of that one thing, possibly; but more probably its connection determines the positive and negative character. The old theory of Franklin, though falling short in some respect, is, from a certain point of view, after all, the most plausible one. Still, in spite of this, the theory of the two electricities is generally accepted, as it apparently explains electric phenomena in a more satisfactory manner. But a theory which better explains the facts is not necessarily true. Ingenious minds will invent theories to suit observation, and almost every independent thinker has his own views on the subject.

It is not with the object of advancing an opinion, but with the desire of acquainting you better with some of the results, which I will describe, to show you the reasoning I have followed, the departures I have made-that I venture to express, in a few words, the views and convictions which have led me to these results.

I adhere to the idea that there is a thing which we have been in the habit of calling electricity. The question is, What is that thing? or, What, of all things, the existence. of which we know, have we the best reason to call elec

tricity? We know that it acts like an incompressible fluid; that there must be a constant quantity of it in nature; that it can be neither produced nor destroyed; and, what is more important, the electromagnetic theory of light and all facts observed teach us that electric and ether phenomena are identical. The idea at once suggests itself, therefore, that electricity might be called ether. In fact, this view has in a certain sense been advanced by Dr. Lodge. His interesting work has been read by everyone, and many have been convinced by his arguments. His great ability, and the interesting nature of the subject, keep the reader spellbound; but when the impressions fade, one realises that he has to deal only with ingenious explanations. I must confess that I cannot believe in two electricities, much less in a doubly constituted ether. The puzzling behaviour of the ether as a solid to waves of light and heat, and as a fluid to the motion of bodies through it, is certainly explained in the most natural and satisfactory manner by assuming it to be in motion, as Sir William Thomson has suggested; but, regardless of this, there is nothing which would enable us to conclude with certainty that, while a fluid is not capable of transmitting transverse vibrations of a few hundred or thousand per second, it might not be capable of transmitting such vibrations when they range into hundreds of million millions per second. Nor can anyone prove that there are transverse ether waves emitted from an alternate-current machine, giving a small number of alternations per second; to such slow disturb ances, the ether, if at rest, may behave as a true fluid. Returning to the subject, and bearing in mind that the existence of two electricities is, to say the least, highly improbable, we must remember that we have no evidence of electricity, nor can we hope to get it, unless gross matter is present. Electricity, therefore, cannot be called ether in the broad sense of the term: but nothing would seem to stand in the way of calling electricity ether associated with matter, or bound ether; or, in other words, that the so-called static charge of the molecule is ether associated in some way with the molecule. Looking at it in that light, we would be justified in saying that electricity is concerned in all molecular actions.

Now, precisely what the ether surrounding the molecules is, wherein it differs from ether in general, can only be conjectured. It cannot differ in density, ether being incompressible; it must, therefore, be under some strain or in motion, and the latter is the most probable. To understand its functions, it would be necessary to have an exact idea of the physical construction of matter, of which, of course, we can only form a mental picture.

(To be continued.)

THE ELECTRIC TRANSMISSION OF POWER.*

BY GISBERT KAPP.

LECTURE I. (Concluded from page 42.)

I need hardly say that, at the present time, no English millowner would dream of working his mill in this fashion by animal power, since coal is yet abundant, and a single steam engine is a far cheaper and handier instrument for producing and controlling a large amount of power than an equivalent number of horses. On the other hand, if power is required in small quantities, and in particular ways, then the horse will produce this power better, more cheaply, and more conveniently than the steam engine. It may seem absurd to work a large cotton mill by horse gear; but substitute for the mill a farm, and you see at once that the transmission of stored power to it, in the shape of corn, is a necessary part of the agricultural operations. Now the horses, in bringing the corn to the place where the power is required, perform work and must consume an equivalent amount of food. They also perform work in bringing the empty carts back again to the field to be recharged.

The ratio between the amount of corn delivered at the mill and the amount taken out of the field would therefore represent the efficiency of transmission. If this is to be 90 per cent., as is the case of electric transmission, we may take it that, for every 100 sacks of corn taken away from the field, the horses would eat on the outward journey (when the carts are heavily laden) 61⁄2 sacks, and on the homeward journey (when they are empty) 3 sacks, leaving 90 sacks of corn to be converted into live power at the mill. The distance to which we can thus carry stored power with a standard efficiency of transmission is a * Cantor lectures delivered before the Society of Arts,

measure of the merit of the system, as far as economy of power is concerned.

The transmission of stored power in the shape of fuel is a parallel case. We load the coal at the pit's mouth into waggons, where the power is wanted. Part of the coal is consumed on and haul them by means of locomotive engines to the places the outward and homeward journey of the train, leaving the rest for the production of live power at the mill. If this amounts to 90 tons out of every 100 tons put on the train at the pit's mouth, we have again an efficiency of transmission of 90 per cent.

I have already mentioned that the exact distance to which we namely, batteries, corn, and coal-depends very much on the can carry power by either of the three agents here mentionedkind of road over which the transmission takes place. Wo might assume an almost infinite variety of cases, but, as our object is to obtain a rough general comparison of the different systems rather than exact figures for any one of them, I have assumed merely three kinds of roads-namely, a common distance to which power can be transmitted in each case with a carriage road, a tramway, and railway-and have calculated the loss of 10 per cent. The results of these calculations are given in the following table. The speed of transmission has been assumed at four, six, and 20 miles for road, tram, and rail respectively, when coal or batteries are the transmitting agents; and at four miles on all kinds of road when corn is the transmitting agent. In all cases I have assumed that the road is the best of its kind, perfectly free from gradients or curves, and that the traffic can be worked at the speeds mentioned without interruption. In reality, these conditions will, of course, not all be fulfilled; we have to make allowances for waste of power on gradients, curves, bad places in the road, for running at variable speed, and for stopping and starting. The distances given in the table are, therefore, throughout too different systems, we may take the figures in the table as a large; but as our purpose is merely the comparison of the rough indication of the merits of each. The figures show the distance in miles attainable with 90 per cent. efficiency of transmission over road, tram, and rail :

TRANSMISSION OF STORED POWER.
Source of power.
Coal and steam engine..

Corn and horse

Storage battery and electromotor...

Road.

Tram.

Rail.

115

270

1,300

52

170

440

The

You will see, from this table, that as regards efficiency the electric transmission of stored power cannot compete with the other two methods. A horse and cart carrying corn over an ordinary carriage road works with twice the efficiency of the electric locomotive taking batteries over a railway. The discrepancy is still greater if we compare the electric locomotive hauling batteries with the steam locomotive hauling coal. latter can transmit power over a distance 50 times that over which the former can transmit power with an equal efficiency. On a tram line the distance over which we can transmit power with an efficiency of 90 per cent. is, according to the table, 10 miles--that is to say, if the whole load of the car is composed of batteries, we can run it 10 miles out and 10 miles home at an expenditure of 10 per cent. of the total charge of the batteries. Now let us see how this compares with the storage cars in use on passenger tram lines. The total weight of a full-sized car is about 10 tons, made up somewhat as follows: car and propelling gear, 4 tons; batteries, 21⁄2 tons; passengers, 31⁄2 tons. If the 3 tons represented by the passengers were utilised for additional storage cells, the car could run 20 miles with the loss of 10 per cent. of its charge; or it could run 200 miles if losing the batteries instead of six tons, it can only run 86 miles. whole of its charge. As there are, however, only 2 tons of the reasons already stated. Experience has shown that storage according to the table, and more than attainable in practice, for teries, or half the distance stated in the table. If we apply the cars can only run from 30 to 60 miles with one set of bat

This is

same reduction to all the methods of transmission, we find that stored form, with an efficiency of 90 per cent., are two, five, the distances to which power can be carried electrically in the and 18 miles over a carriage road, tramway, and railway respectively.

the most important consideration in the problem of transmitting The efficiency of transmission is, however, not the only or even power to a distance. The owner of a transmission plant cares efficiency. All he cares for is the cost at which the power is nothing for any theoretical perfection in the way of high delivered to him. All other things being equal, high efficiency will naturally reduce this cost, and in so far is an advantage, but in practice all other things are not equal, and to aim at high efficiency regardless of other considerations is the reverse of good engineering. It is no doubt gratifying to the engineer if he extraordinarily high efficiency, but if this result has been obtained can point to a transmission plant designed by him to give some by means of an exorbitant capital outlay and excessive working expenses, it will not be equally gratifying to his employer, the owner of the installation, who has to pay for its erection and working. It therefore becomes the duty of the engineer so to