Bath he had only spoken of in connection with a high tension system and in such cases their use was justifiable, for the amount of copper was so small that ample fallowance could be made for increased demand. The figures he had given respecting the cost of Mr. Crompton's mains had been arrived at by careful estimates prepared by a surveyor and himself, which gave £130 as the cost of 100 yards. In the table given by Mr. Crompton it was hardly fair to put a pipe with a hole 1 inches diameter on the same footing as a 2-inch or 24-inch way in a Callender-Webber casing; and if this were taken into account, the difference in cost would be rather the other way. This difference would not be large for ordinary sized mains, and, as he had pointed out on page 19, bare copper conductors were cheaper when the section exceeded 14 square inches.

1,923. Improvements in electrical switches." G. BINSWANGER. Dated February 3rd.

1,928. Improvements in the method of, and means for increasing the strength, volume, or intensity of sound during transmission, applicable to telephones, microphones, phonographs, and other sound transmitting and emitting instruments and apparatus." C. H. DEMUTH. Dated February 3rd.

1,963. "Improvements in methods of and apparatus for electrically soldering cans and other sheet metal ware.' M. W. DEWEY. Dated February 3rd. (Complete.)

1,968. 'Improvements in and relating to electric lamps or lighting apparatus." H. H. LAKE. (Communicated by F. V. Macquaire, France.) Dated February 3rd.

1,969. "Improvements in electrical signalling apparatus." H. H. LAKE. (Communicated by S. J. Burrell, United States.) Dated February 3rd. (Complete.)

1,987. Improvements in electric lamps." A. M. CLARK. (Communicated by J. W. Easton, United States.) Dated February 3rd. (Complete.)

1,988. "Improvements in autographic telegraphs, and automatic switches for the same." O. IMRAY. (Communicated by the Writing Telegraph Company, United States.) Dated February 3rd. (Complete.) 1,994. An electric light lamp shade." G. BELT. Dated February 4th.

2,009. "Electric thief and fire alarm." E. BERG. Dated February 4th.

2,010. "Improvements in signalising telegraphs. E. BERG. Dated February 4th.

2,033. "Improvements in dynamo-electric machines." W. LOWRIE and R. HAMMOND. Dated February 4th.

2,045. Electrical ore stamping and pulverising apparatus." R. R. HUTCHINSON. Dated February 4th.

2,046. "Improvements in and relating to electrically propelled vehicles, especially adapted for high rates of speed." R. R. HUTCHINSON. Dated February 4th.

2,061. "Improvements in electric lamp holders." W. P. THOMPSON. Communicated by J. B. Moore, United States.) Dated February 4th. Complete.)

2,067. "Improvements in electrical transformers." C. BAUR and W. DIESELHORST. Dated February 4th.

2,115. "Improvements in or connected with metallic gauze brushes employed in dynamo-electric machines." J. D. and C. JUBB. Dated February 5th.

2,152. "Improvements in electric switches." J. C. WOODBURN. Dated February 5th.

2,165. "Improvements in armatures for dynamo-electric machines." J. NEBEL. Dated February 5th.

2,180. "Improved means or appliance for fixing or driving staples or like devices, especially applicable to electrical fittings." G. T. MACKLEY. (Communicated by C. Mackley, Germany.) Dated February 6th.

C. W.

2,199. "Improvements in automatic electric switches." Cox, F. ROBINSON, and W. H. GRITTON. Dated February 6th. 2,200. "Improvements in or relating to electro-motors." E. ATTENBOROUGH. Dated February 6th.

2,201. "6 Improvements in laying and insulating underground mains for carrying electricity." J. E. SPAGNOLETTI. Dated February

6th.

2,219. 61 Improvements in electric arc lamps." E. E. LEVER. Dated February 6th.

2,225. "Improvements relating to motors for electric railways." J. B. BERLIER. Dated February 6th.

253

2,289. "Electrical block signalling apparatus for single line railways." SIEMENS BROTHERS & Co. (Communicated by Siemens and Halske, Germany.) Dated February 7th.

2,297. "A method of, and apparatus for, prolonging the life of the carbons in electric arc lamps." C. W. HAZELTINE. Dated February 7th. (Complete.) [Date applied for under Patent's Act, 1883, Sec. 103, 9th July, 1890, being date of application in United States.]

ABSTRACTS

OF PUBLISHED SPECIFICATIONS, 1890.

1,644. "Improvements relating to electric traction." A. L. LINEFF. Dated January 30th. 1s. 1d. Relates to improvements on letters patent July 11th, 1888, No. 10,092. 5 claims.

3,574. • Improvements in distributing electricity." H. R. Low and G. E. B. PRITCHETT. Dated March 6th. 4d. The inventors generate a "direct" current of electricity by means of a dynamo or other suitable method, and store it in accumulators; the discharge from these accumulators is utilised in operating a direct current motor or motors to which are coupled in any suitable manner a dynamo or dynamos generatiug an alternating current of high electromotive force. This current may be distributed by means of secondary generators or otherwise. 3 claims.

4,103. 'Improvements in electric arc lamps." J. CAMPBELL. Dated March 17th. 6d. Comprises an electro-magnet in the main circuit which upon the current passing it attracts an armature, on one end of what may be termed the striking lever, to the other end of which lever is attached springs connected respectively to one end of the lever grips, to which same end of grips are attached, connecting rods connected at other ends to what may be termed the feed lever, provided with an armature actuated by a high resistance coil, which is in shunt to the lamp circuit. The lever grips before referred to consist each of an ordinarily flanged socket, on one side of which is fulcrumed the grip, consisting of an angled lever, one arm of which acts on the carbon rod, which, when the compression caused by the shunt coil is on, releases said grip and allows the carbon rod to feed down. The springs before referred to each suspend a carbon rod and keep the arc always formed, and thus prevents the upper carbon from falling on the lower while current is flowing. 3 claims.

4,191. Improvements in methods and mechanism for generating heat, steam, and light by electricity." T. D. FARRALL. Dated March 18th. 8d. Embodies the combinations of dynamo-electric machines, storage batteries, or accumulators, or other electric supplying mechanism, electric heating cartridges, steam generating boilers, steam engines, and electric lighting apparatus, and embraces other mechanism and certain details of construction relating thereto, by which electricity, heat, steam and light are generated and applied without the use of coals or other fuel, for heating, for motive power, and for lighting purposes, and by which surplus power and exhaust steam and momentum are utilised for the same, and by which heat, steam, and light are generated and applied by electricity from a central electric plant or plants, or other sources of electricity, by the present means now in use or otherwise. 46 claims.

5,764. "Improved system of electrical inter-communication for telephonic purposes." W. P. THOMPSON. (A communication from abroad by A. W. Berne and B. W. Taylor, of America.) Dated April 16th. 6d. Relates to a system of electric circuits for telephonic purposes in conjunction with switches, connections, and cut-outs, and the objects of the invention are to permit six persons to converse with each other, without interference, upon three wires, or to enable one person to converse with another at any telephone, and whereby perfect metallic returns may be had at any time by the use of the switches, as shown in the drawing. 3 claims.

6,124. "Improvements in manholes for underground electric conduits." J. F. MUNSIE. Dated April 22nd. 8d. Has for its objects, firstly, to avoid explosions therein by keeping the man-hole chamber practically air and gas-tight; secondly, to maintain said chamber in as dry a condition as possible; thirdly, to make suitable provision for ensuring the safety of the linemen entering the chamber; fourthly, tc minimise or neutralise the injurious influence of induced currents from high tension wires upon low tension or battery wires passing through the man-hole chamber; and fifthly, to provide access to the man-hole chamber from the side and through a constantly ventilated shaft or well furnished with dry air. 13 claims.

6,126. "Improvements in electrical signalling apparatus for police service and the like." R. D. RADCLIFFE. Dated 22nd April. 6d. Relates particularly to electrical signalling apparatus of the type known as district or messenger calls, and it has for its object the simplification or arrangement of parts whereby two or more types or kinds of individual wants may be signalled from a single box and single wheel cylinder or transmitter. 6 claims.

7,433. "Improvements in telephones." W. VOGEL and G. G. CALKINS. Dated May 13th. 8d. Claims:-1. A telephone embracing a magnetised strand or core extending from the transmitting to the receiving station, and transmitting and receiving devices comprising vibrating armatures located adjacent to the ends or poles of said strand or core, substantially as described. 2. The combination with a wire or core and electric circuit or circuits, comprising coils surrounding the said wire or core, and a shell or casing surrounding the end or pole of the said wire, and provided with a diaphragm arranged opposite the said pole and with a flexible tube having an ear-piece in communication with the interior of the shell, substantially as described.

254

7,836. "Improvements in electric semaphores for railways." F. STITZEL, C. WEINEDEL, M. J. SCHWARTZ, A. REUTLINGER, J. H. EGELHOFF, and J. KREIGER. Dated May 20th. 11d. Relates to an improvement in electric semaphores for signalling railroad trains and more particularly to such as are adapted for use in connection with the "block" system. The object of the invention is to provide a signalling device for exhibiting "danger" and "safety" signals along a line of railroad to denote whether or not a certain predetermined portion of said railroad is occupied by a train. 17 claims.

7,853. Improvements in welding metals electrically, and apparatus therefor." W. P. THOMPSON. (A communication from abroad by C. L. Coffin, of America.) Dated May 20th. 8d. Claims:-1. The described method of welding metals electrically, consisting in making contact between the two parts to be welded and an electrical conductor, passing heating currents through the articles to be welded and said conductor, removing the articles to be welded from contact with the conductor when brought to a welding heat, and pressing them together to form the weld. 2. The described method of welding metals electrically, consisting in making contact between the two parts to be welded and an electrical conductor, establishing an electric current through the articles to be welded and said conductor, slightly separating the ends of the articles to be welded from said conductor, thus forming a voltaic arc, and pressing the articles to be welded together to form the weld. 3. The various forms of apparatus for welding metals electrically taken as a whole, substantially as described.

7,871. "Improvements in electric signal circuits." O. W. HART. Dated May 20th. 6d. Consists in providing the main circuit with a magnet of high resistance connecting a shunt circuit with the main circuit and providing the shunt circuit with a magnet of lower resistance. 1 claim.

8,362. Improvements in electric locomotives." E. DUMMER. Dated May 30th. 8d. Consists, fundamentally, in an electric locomotive so constructed as to embody one or more field magnets connected with the driving wheel or wheels to revolve therewith. Each of the magnets may be magnetised constantly, and thus be supported as one body with the wheel or wheels directly by the rails of a railway. The invention also consists in the combination of gearingwhen gearing is required-and other parts of the motor and motive mechanism with the driving wheel or wheels and frame of the locomotive, as described. 6 claims.

8,703. Improvements in electric welding." W. P. THOMPSON. (A communication from abroad by C. L. Coffin, of America.) Dated June 5th. 6d. Claim:-The described method of electric welding, consisting in placing the parts to be welded in close proximity to a voltaic arc, protecting the arc and the parts to be welded by a jacket of non-conducting refractory material, and, after sufficiently heating the parts, pressing them together to complete the weld.

8,730. "Electric soldering irons." W.M. MINER. Dated June 5th. 6d. Consists of the usual solid head of copper, in combination with a heating resistance placed on the outside and surrounding the same. A shell of non-heat-conducting material is placed over the resistance to concentrate the heat upon the copper and to prevent its dissipation. 6 claims.

9,124. Improvements in electric time counters." J. J. A. AUBERT. Dated June 12th. 6d. The counter consists of a clock movement and a commutator which, by closing and opening the circuit, causes simultaneously and respectively the starting and stopping of the clock movement. The commutator acts mechanically upon the balance of the clock movement, as is hereafter described. There is a key at the front face of the counter; this key is moved by hand or by the aid of any suitable arrangement. 3 claims.

10,124. "Improvements in electric heating apparatus. M. W. DEWEY. (Under International Convention.) Dated December 13th, 1889. 8d. Consists, essentially, in the combination, with suitable supply-conductors, of a resistance or radiating device composed of thin flat sheets of metal, preferably iron, connected together in series; and it consists further, in arranging the sheets parallel, side by side, and with air-spaces between them, and also arranging the heating device so that one end will have free movement longitudinally within the frame or case to allow for expansion and contraction due to heating by the passage therethrough of the electric currents and cooling upon the cessation of the currents. The said movement is utilised to operate a suitable circuit maker and breaker to prevent undue heating of the device. 12 claims.

10,125. "Improvements in electric cut-outs or apparatus for controlling the flow of currents of electrical energy." J. L. KIMBALL and H. C. WIRT. Dated July 1st. 6d. Is particularly applicable to main and branch cut-outs used in connection with a moulding, concealed or cleat work, secured to the walls of a building, and has for its object to improve the construction of the same, whereby a smaller, neater, and cheaper cut-out is obtained. 3 claims.

10,179. Improvements in telephone call devices." H. J. HADDAN. (A communication from abroad by F. R. Spalding, of America.) Dated July 1st. 6d. Relates to improvements in call devices for telephones, and it has for its object to enable the operator at the central station to ring up any one of the telephones on the line (in a block of from two to about ten) without ringing up the others, and this is done by means of a magneto generator of variable strength at the central office or exchange and individual call bells on the telephones in the block system, which bells are actuated and sounded according to the strength of the magneto electric current sent through their respective electro-magnets. 2 claims.

10,188. "Improvements in electric cut-outs." A. J. BOULT. Ꭺ communication from L. B. Favor, of America.) Dated July 1st. 8d. ates to devices for the protection of low tension electrical circuits, as for its object to obviate any danger or damage that might re

[FEBRUARY 20, 1891.

Dr. Silvanus Thompson's Letter.

On the strength of a reference to a published work of the late Fleeming Jenkin, drawn up presumably a good many years after the formation of the British Association Unit Committee, Dr. Silvanus Thompson charges me with having made an egregious mis-statement. Sir William Thomson

once referred publicly to the mistakes made by that committee as being "to our shame;" but should he as one who was a member of it at its first inception, feel himself justified in stating that the committee, when it first commenced work, practically recognised and dealt with the fact that copper conductors opposed inertia resistance to transient currents, and that the committee were also aware that similar conductors made of different samples of copper, when forced at an equal rate of speed through the lines of force of our terrestrial magnet were not affected equally, then I will acknowledge that I have been labouring under error, and I will frankly apologise for having made a mis-statement.

The article on "Posthumous Scientific Honours" in the same issue as that containing Dr. Thompson's letter affords evidence, that Dr. Silvanus Thompson himself, as a professor of scientific history, is not always to be absolutely trusted, and I must be forgiven if I refuse to accept off-hand the reference he makes to Fleeming Jenkin's book as a refutation of what was incidentally mentioned by me in a published article.

The late Fleeming Jenkin, in the earlier days of the Unit Committee, was the most active member of it, as well as the secretary, and it is only human that, when drawing up the reports many years after the formation of the committee, that he should not make the most of mistakes which had been made; and, further, no useful purpose would have been served by his enlarging upon errors after the committee had become aware of them.

It has occurred to me at times, that, the history of the British Association unit of resistance, from a practical man's point of view, ought to be written, and Dr. Silvanus Thompson's letter may perhaps induce me to attempt the task, but I must be allowed now to say that the way the standards were produced and issued in the first instance was not such as to inspire confidence in their accuracy. Speaking as a practical man, the conditions under which they were made I consider rendered it almost impossible that the authorised copies should agree as closely with another as was practically attainable and desirable in authorised standards of resistance.

So soon as it was officially notified that standard coils were obtainable by payment, I ordered six copies, but received only one; I was, however, given to understand that the others would be supplied shortly. Later on I was advised that an error had been detected in the standards sent out, and another standard resistance was sent to replace the one I had already received. I then wrote to Mr. Fleeming Jenkin, saying I did not consider it safe to rely upon a single standard, and if it were not convenient to let me have the six ordered, could he not let me have a duplicate, and this he promised to do, but it never came to hand. I applied again and again, but was always put off with excuses from week to week and month after month, and at last I was reluctantly forced to the conclusion that for reasons best known to Fleeming Jenkin he had all along never intended me to be supplied with a duplicate standard. The fact that there was some objection to letting me have more than

FEBRUARY 20, 1891.]

one copy of the standard resistance speaks volumes in itsel. My testing arrangements at that period were, I think, more perfect than those at the command of Fleeming Jenkin, and possibly it was not considered prudent to let me have two copies, as in that case I could have compared them.

Months elapsed, and I had to rely upon the single standard after all. I took infinite pains to secure accurate copies of it. My testing room had been specially built for the purpose, with solid brick walls and a thick well insulated roof; the temperature was maintained constant by a hot water system heated by gas, turned on and lowered automatically by a heat regulator, which spoke to one-tenth of a degree Fah., and the temperature, as indicated by three maximum and minimum thermometers, did not vary for months together half a degree. The final testing was done in all cases in the small hours of the morning, as that was the only time when everything was really quiet and still, and I spent upwards of £300 building up resistances before I considered myself in a position to manufacture resistance coils for the market; at the same time I never had any confidence that the standard coil supplied me agreed other than approximately to those issued to others; the only thing I could be really sure of was that my resistances were true to

one another.

At a later date I found, as a matter of fact, my copies of the standard resistance differed from the copies made in Sir William Thomson's laboratory, and this led to some correspondence, Sir William very kindly promising to send me a box of resistances, which he said he thought I I could depend upon as being very accurate; but they never came to hand. I am quite sure Thomson himself intended them to be sent to me, the fact that I did not receive them I attribute to others, and not to Sir William Thomson himself, Dr. Silvanus Thompson has been good enough to credit me with setting right distinguished physicists during the last twelve months. I claim to have been setting them right, and to some purpose, since 1887. In December, 1887, I directed public attention, among other things, to certain discrepancies between what was published in "Dynamo-Electric Machinery," and that which was contained in affidavits which had been made in connection with a law suit at that timelately settled-and I so successfully educated certain eminent physicists, that when at a later date (1888), as a consequence of my initiative, the respective claims of myself and Brush to be considered to have been the first to have described a system of compound-winding, came before the Scotch law courts, these now educated physicists sang an altogether different song to that contained in the affidavits sworn to in the previous case. One distinguished physicist professed to be puzzled, a second distinguished physicist declared that my 1876 machine at the time it was made ought to have been "chucked on the dust heap," and a third declared my dynamo-electric theory to be absurd, and they all did their very best to try and persuade the court that my 1876 machine was separately excited, notwithstanding it had been most confidently asserted in the affidavits sworn to in the previous case, that this same machine of mine was evidently a double-shunt dynamo. Dr. Silvanus Thompson can scarcely have forgotten that Lord Trayner did him the honour of specially referring to his evidence in opposition to my claim, the court describing it as neither reasonable nor fair: and he also, possibly, remembers that Lord MacLaren, when confirming the judgment given by Lord Trayner, appealed against, said that "he had a difficulty in understanding that a considerable number of able and distinguished men should have been persuaded to give their evidence as to the alleged insufficiency of Mr. Varley's description as an anticipation."

It is too much, perhaps, to expect under the circumstances that I should be altogether a persona grata in the eyes of Dr. Silvanus Thompson, but the electrical industry may possibly regard it as a matter for congratulation that I did undertake the task of setting right certain very eminent physicists, seeing that my having done so has been the means of relieving the industry since 1888 from having to pay royalties amounting in the aggregate to many thousands of pounds."

I was informed by one of the larger dynamo-electric firms in 1888 that the loss of business arising out of the fact that they had to pay royalties on compound-wound dynamos was very much greater than the amount paid as royalty.

255

Now, had I not succeeded in putting right distinguished scientists, the dream of whose lives, if we may believe them, is to see energy laid on electrically in every household, much in the same way as water and gas, then these very able men would in all probability have succeeded in prolonging the monopoly for eight more years, dating from next May, and in that case they-the scientific enthusiasts-would have found the realisation of their ardent dreams deferred, and they would have been compelled to find a solatium for their disappointment as best they could, in the shape of substantial professional fees. S. Alfred Varley.

February 13th, 1891.

Storms and Telegrams.

66

I am really much obliged to Messrs. Slingo and Brooker for their frank and unbiased opinion of the A-pole, contained in their interesting article in to-day's issue of the REVIEW. These gentlemen are possessed with mechanical brains, and it cannot be said they are minus a reasonable knowledge of the subject on which they venture to write," like, it will be remembered a certain individual, who tried hard to kick my A-pole out of the earth, appeared. I quite concur in all they say about a strutted single pole and an H-pole, and as a proof that their remarks in regard to the A-pole are correct, one has only to look at the Eiffel Tower, or the main tubes of the Forth Bridge, which represent, in each case, two gigantic As braced together. I am sorry the gentlemen cannot afford the time to make the inspection as suggested, because I feel sure that they would not regret such, the line of A-poles being the most extensive and exposed in the country. As to a line of these poles being unsightly, I think they are the opposite, when properly constructed, i.e., the poles paired and spliced together, so that the bends are always inside, thus A, the space or spread of the legs uniform, and the heads level, not bobbing up and down. This is all carried out on the sections named.

May, I ask, where has the individual gone to? I would say, wake up Jno. McDonald and show that you are a true Highlandman, and if any apologies to make, make them now, like a gentleman, or never. It would amuse electrical engineers to refer to the scurrilous and prejudicial letters in the REVIEW of August 3rd and 17th, 1888, and February 15th, 1889, by this individual, after the able articles by Messrs. Slingo and Brooker.

February 13th, 1891.

Arthur E. Gilbert.

Electricity as a Measure of Thought.

I crave your indulgence to make known an idea that has occurred to me, relating to that most important and little understood human function, thought. It is well known to the medical profession that every mental effort causes a rush of blood to the brain, and that the amount of blood depends on the "intensity" of the thought; but rush of blood means a rise in temperature, and if we could measure this we would be able to determine, in a rough way, the "power" necessary for the generation of any thought or mental effort. I accomplish this object in the following manner :-I have a head gear of some light, high-conducting (heat) substance, in its middle or any other convenient position. I fix a thermoelectric pile, and connect this, by means of flexible wires or otherwise, to a sensitive galvanometer. The extreme sensibility of the thermo-electric pile is well known, and therefore whatever rise in temperature takes place, consequent to the rush of blood, would be instantaneously indicated by the galvanometer. The utility of such an apparatus may not appear at first sight of great importance, but if we consider for an instant the facility or difficulty with which children at school learn their lessons, any doubts we may have entertained as to its practicability will be immediately dispelled. By such a contrivance would we ascertain the "brain power" of boys and girls-nay, even men, and thus be in a position to indicate in what direction their mental efforts ought to tend. To make my meaning plainer. Certain scholastic tasks, such as drawing, could be performed without the expense of great energy on the

256

part of any particular pupil. Well, this very same individual would probably encounter greater difficulty and consequently expend a large amount of energy in the solution of a mathematical problem; it is true that these subjects are not equal in "hardness in relation to the same person, or that the two tasks, when compared to a "standard"-by their generation of heat-will differ in degree, even in an individual of all-round capacity; yet if their relative "hardness were at first roughly or arbitrarily settled, comparisons amongst the different individuals could then be instituted. Of course, several tests would have to be taken under varying conditions and at different epochs before arriving at any definite and reliable' conclusion, since a good many factorsapparently the most trivial-such as the state of the body, through indifferent, bad or good nourishment, &c., would have to be taken into account. And, if such a system of tests were periodically carried out, it would be the means of allotting to each individual the task for which he shows the greatest aptitude; that task that could be performed by the said individual with the least waste of "brain energy," or in other words, that task most congenial to his tastes, whence more profitable to the community. The "waste of brain energy "that occurs at school and in active life is very seldom taken into consideration; the over-taxing of the brain, by setting it to perform relatively hard tasks, is attained by most deplorable consequences; over-strain leads to mental aberration.

Again I repeat: If some such system as the one suggested were to be adopted, we would hear less and less of human breakdowns, and alas! of juvenile suicides. The idea is capable of great modifications; may be a sensitive microphonic arrangement, working in circuit with a sensitive receiver, to whose diaphragm a stylus would be attached, tracing against travelling paper, would also answer the pur

I had not thought necessary in my first letter to insist upon the practical success of the Norddeutsche Affinerie, of Hamburg, because it is well known to all specialists that the Hamburg installation is, up to the present, the model of perfection of the kind. It was organised and has since been conducted by Dr. Wohlwill, who is simply a chemist and electrician of talent and great practical sense; the fact that the Affinerie has been working steadily since 1873 with the highest known efficiency-unapproached yet by any existing establishment -shows sufficiently that it is a well conducted business. The cost of the metal deposited is under £8 per ton, including everything; the electrolytic copper, of great purity, is sold at the usual prices, and the cost of work is balanced by the sales; the recuperation of precious metals-though naturally variable-consequently makes the business excellent and very profitable. No success, however, can be obtained without a solid base, and in that installation everything is designed and conducted upon scientific principles; nothing is neglected of the multiple factors contributing to the efficiency of the plant.

The best installations after that of Hamburg are each one designed to take advantage of some special condition, and are generally well conducted; they produce, however, at an expenditure per ton of copper deposited, of nearly double that of the affinerie of Hamburg. It must be understood that I have in view here only rational installations designed by competent men knowing the conditions of efficiency of the work, and where the deposition is carried out in series of from 40 to 70 tanks with active surfaces of from 90 to 125 square metres per horse-power, having their respective distances and direction accurately determined; in none, of course, are the surfaces in opposition arranged in such a manner that the transport has to be effected against the laws of gravity, as is the case in the Elmore process; this alone is a commercial absurdity.

I have nothing to say, nor would I give an opinion on

[FEBRUARY 20, 1891.

enterprises of a speculative character, but those interested more or less in the question of electro-deposition have probably read the report of a visit to the works of the Elmore Company, and if the sketch given in the ELECTRICAL REVIEW of January 30th ultimo is correct, as well as the statement that 75 H.P. are required (and considering the very small quantity of metal that can be deposited under such conditions of work as those illustrated, it cannot be otherwise), it is plain that the economical conditions of the process are simply disastrous, so far as the cost of electrolytic copper is concerned, and unless an immense sale is obtained for the manufactured articles, which might be turned out in formidable quantities from future works of unusual magnitude (existing already on paper), but which should be designed in a somewhat different way in order to reach a reasonable rate of efficiency, I am afraid that harvest of gold-even supposing an abnormal percentage of the precious metal in their raw copper-will not be for those who have given their money.

In this admirable country for business, anything can be financed with suitable reports and a few well known names. If the reports required by the Elmore Company had been made, for instance, by my eminent colleagues, Hospitalier or by our actual President, H. Fontaine, whose authority and strict characters would have been an absolute guarantee for the public, it is probable (supposing they had consented to report, and supposing the report had been favourable) that the scheme would have met with less favour, for want of the common sort of popularity of the reporters. On the other hand, if the report of M. Secrétan had been made in France for a first start in that country, I believe the choice of such a technical authority would have been sufficient to prevent the floating of the company. The report would have been taken as a pure farce, in spite of the too great popularity of recent date of that gentleman, for the simple reason that he has no knowledge of the question on which he has reported. His great competency, besides his original trade and clever manufacture of optical instruments, is in paintings and works of art of highly speculative character from artists à la mode, and the few electricians who know him personally must have been much amused to hear of a report on electro-depositing devices made by M. Secrétan, who had probably never seen a copper-refining tank before he went to Leeds.

I hope this will suffice for the present. I am afraid I have already encroached too much upon your kind hospitality.

Dynamo Cost.

L. Falero, M.F.S.T.E.

BATTERY TRANSFORMERS.

SINCE the futile attempt to carry out the lighting of Colchester by means of direct currents and secondary battery transformation the pioneers of this system have not been idle. The first failure was due, no doubt, to want of experience, and the absence of perfection in the various details that go to make up a complete method of distribution, and most engineers profiting by the lessons taught by this experiment somewhat modified their views on the subject, but the inventors still clung fondly to their old plans, and waited for a fitter opportunity to put them into practice.

When the electric light industry had recovered from the effects of rash speculation and prohibitive legislation, and encouraged by success abroad, was again tempted to solve the problem of the economical distribution of electricity, a new competitor had entered the field, the alternate current transformer; a spirited contest took place between the two systems, and was fought out by the leading advocates of both sides in the arena of the Institution. The result at the time was a drawn battle, and it was left to practical experience to determine the survival of the fittest, and to evolve a complete ystem of distribution which should be commercially sucessful. At the time that the various schemes for the supply the metropolis were brought forward, the Board of Trade dopted this view, and parcelled out the districts between he different competitors, seeking, where possible, to place e alternate and direct current systems in opposition, by ving them concurrent rights over the same arcas, so that he general public might at least have a double chance of a tisfactory solution of the question.

Six principal companies shortly entered the field, each pical of its kind, viz., the London, with a double transrmation from 10,000 volts; the House-to-House transrming from 2,400 volts, and the Metropolitan transforming om 1,000 volts. These three were on the alternate current stem. The direct current system was represented by the Belsea Company transforming from about 1,500 volts by

means of secondary batteries and storing the whole amount ; the Kensington and Knightsbridge running on the threewire system and storing one-fifth of its output; and the St. James's and Pall Mall working direct on a three-wire system without storage. Later on the Westminster Company commenced work on the same lines as the Kensington and Knightsbridge.

In Major-General Webber's recent paper read before the members of the Institution of Electrical Engineers, he refers back to his contribution to the B.A. at Newcastle in 1889, since which date the Chelsea station, according to the author, has got to work, and proves a perfect success in every way. The automatic apparatus is afterwards described, in which many who once expressed disbelief are convinced of its utility. The opinions of other equally experienced men, however, of such automatic work is, that it is unwise to have anything to do with it.

E.M.F. governors with fine shunt coils, having important action dependent upon them, are unadvisable; they are too liable to be broken by accident. The automatic arrangement may be a most beautiful piece of mechanism, but it is not engineer's work, and it is certainly not a desirable thing for public lighting. Any hitch in the working would be attended with grave disaster.

Charging accumulators in series has been generally fatal to the batteries. In charging three stations in series, all the batteries are equally charged; but unless the districts get an equal discharge, they get out of order, and it requires very careful superintending on the part of the engineer to keep them in condition. There might be a very heavy discharge in one district, and a very slight one in the others, and to make them equal, the engineer has to pump out the other batteries; that was the one serious defect at Vienna, and there is very little difference between Chelsea and Vienna, almost the same number of batteries being employed. Charging at the latter place was performed in series, and discharge taken off in parallel, but fortunately most of the current was sent direct into the lamps. The great difficulty