798

Finding that cadmium volatilised so readily under the action of the induction current, a large quantity, about 350 grs., of the pure metal, was sealed up in a tube arranged as in fig. 8, and the end of the tube containing the metal was heated to a little above the melting point; the molten metal being made the negative pole, in a few hours the whole quantity had volatilised and condensed in a thick layer on the far end of the tube, near, but not toucl.ing, the positive pole. (To be continued.)

ABSTRACTS

OF PUBLISHED SPECIFICATIONS, 1890.

536. "Improvements in dynamo-electric generators and motors." C. W. ATKINSON and L. B. ATKINSON. Dated January 10th. 6d. Has for its object in general the provision of means for enclosing the brushes and commutators of such machines, so as to render them suitable for working in the presence of inflammable or explosive atmospheres, and in particular to improvements in the arrangement and construction of the comm.:tator and brushes, as described in Patent No. 16,623, 1887, in which the brushes and commutator are enclosed within a casing in such a manner as to prevent any ignition of the explosive atmosphere being effected from the interior by the sparking of the brushes. 3 claims.

667. "Improvements in electrodes for voltaic accumulators." W. P. THOMPSON. (A communication from abroad by the Hess Electric Storage Battery Company, of America.) Dated January 13th. 8d. Consists in a covering, strata, or layer of the material known to the trade as glass wool, which is made up of finely divided fibres of glass, or glass in a fibrous state, which is therefore highly porous, said glass wool being placed or spread over the face of the active material, or material to become active, and held thereon by a perforated plate of rubber, or any other material not subject to the action of the electricity or solution, or by an insulating strip or strips of a like material, so that, when joined with other plates, a free space between the plates is provided for the circulation of the hydrogen. 4 claims.

669. "Improvements in electrical cut-outs or safety fuses." J. PULUJ. Dated January 13th. 8d. Consists of a platinum wire introduced into a small glass tube closed at either end, so as to form an absolutely fireproof cut-out for electric conductors which may be used even in the midst of explosive gases without any danger whatever. 6 claims.

965. Improvements in therapeutic magneto-electric machines." H. H. LEIGH. (Communicated from abroad by J. B. Gardiner, of America.) Dated January 20th. 8d. Consists in mechanism whereby the operation of the pulls and the actuation therefrom of the electro-magnetic devices are rendered continuous and efficient, means whereby the resistance to the pull of the operator may be varied or adjusted at will, to suit different individuals; devices whereby the force of the series of electric impulses may be varied at will, or, if desired, whereby the entire alternating current ranging from zero to the maximum intensity may be received through the operator's person, instead of the successive impulses which are selected and received in the ordinary operation of the machine; means also whereby the general force of the current may be affected by a magnetic shortcircuiting of the field magnet, combined with means for shutting off this general current entirely by electrically short-circuiting the current through the body of the field magnet; and, lastly, a general construction whereby the entire mechanism is made efficient. 21 claims.

1,114. Improvements in electric railways and in apparatus for the propulsion of vehicles by electricity." A. CHURCHWARD. (Communicated from abroad by A. J. Robertson, of New York.) Dated January 21st. 8d. According to the said invention the main wire or cable for conducting the electric current from the generator to supply the electric motor or motors of the vehicle or electric locomotive, and the return or supplementary wire or cable, are arranged upon the ground. The said main wire or cable, moreover, is passed over a flanged or grooved wheel or pulley placed between the wheels of the said vehicle, thus enabling the contact therewith to be formed and preserved, and assuring a perfect electrical connection, keeping the wire in a good condition, preventing the possibility of contact being formed therewith by the street traffic, and protecting it from ice and show. 4 claims.

4,235. "Improvements relating to filaments for electric lamps for signalling and other purposes." J. P. REES. Dated March 18th. 6d. The improved filament is so formed that, when the electric current is passed through it, the said filament will present the appearance of a spot or disc of light, which can be so placed relatively to the lens that the focal axis of the said lens will extend through the centre of the said disc of light. 2 claims.

4,200. Improvements in or appertaining to automatic safety Appliances or cut-outs for use in systems of electric distribution." WP THOMPSON. (A communication from abroad by C. G. Young, of America.) Dated March 18th. 8d. Consists of the combination of a source of electricity such as a dynamo or dynamos; a main line in oirouit therewith, electric contact terminals normally in closed pirit with and between the poles of said generator and said main Ime for the purpose of maintaining proper electrical connection between the dynamo and main line during the proper working of Vhe system, and automatic means, such as an electro-magnet, for elec

Y separating said terminals upon rupture of the main line, the 'hing of iron in pr in whole, and being normally held eek.-EDS. ELEC. REV.

[JUNE 19, 1891.

closed by the power of the magnet whereby they spring open or fall apart when the main line becomes ruptured. 19 claims.

5,678. Improvements in electric tension regulators or apparatus for automatically controlling or regulating electric currents." J. KALB. Dated April 15th. 8d. Relates to a resistance frame consisting of coils or helices, preferably of German silver wire, which are connected together in a closed series by contact plates or pieces connecting the several coils at the opposite ends thereof, so as to form the continuous series thereof, the series being finally connected at each end to terminal screws. The said coils or helices are connected to wires, preferably of iron, which project in pairs to varying distances, and are connected by two series of wires with the aforesaid coils or helices between the same, one wire of each pair leading from, say, the upper connecting plate or the like of the coils, and the other wire of each pair leading to the opposite connecting plate, or the like, so that more or less of the coils can be switched in or out to increase or decrease the resistance in accordance with the condition of the current. 3 claims.

6,005. "Electric lamp adjuster." G. H. SAYER. Dated April 21st. 6d. Consists of a spring lever clip of a suitable shape, attached by suitable means to the lamp-holder. 1 claim.

13,799.. "Improvements in electrical signalling and in apparatus therefor." H. H. LAKE. (Communicated from abroad by the Electric Secret Service Company, of New York.) Dated September 2nd. 8d. Relates particularly to electrical signalling devices of the type known as individual call apparatus, in which any one of a series of out-lying signal receivers, located on a single or common main line, may be called or signalled to the exclusion of all the others not wanted. 25 claims.

18,266. "Improvements in conduits for electric tramways." H. J. DAVIES and L. B. S. DUTSON. Dated November 13th. 6d. The subway conduit or tube will consist of a channel formed of terracotta, earthenware, delph, or other approved non-conducting material, protected on the upper surface by means of steel rails, which are held in position by cast iron yokes, at such intervals as may be necessary, and the yokes are secured to the ordinary tram rails by means of tie bars, so as to keep the gauge of tramway uniform. At necessary intervals are specially constructed boxes or chambers lined with the aforesaid terra-cotta, earthenware, delph, or other approved non-conducting material, such boxes being connected with the street drain or sewer, so as to carry off surface water or sludge. 4 claims.

20,126. "Improvement in galvanic batteries." C. E. DUTTON. Dated December 10th. 8d. The objects of the invention are to secure in a battery stability or fixity of its internal parts in their proper relative positions, to the end that constancy of current and a prolonged run of a single charge may be attained without restriction of the rate of discharge, automatic circuit connections, and portability of such a character, that the cell may be roughly handled and carried about either in vehicles or by hand without danger of breakage or derangement. 16 claims.

20,540. 'Improvements in welding or otherwise working metals electrically." W. P. THOMPSON. (A communication from abroad by C. L. Coffin, of America.) Dated December 16th. 6d. Claims:-1 The described method of electrically welding metals, consisting in connecting each article with one pole of a generator of electricity, making contact between the ends to be welded and an electric conductor of equal or less resistance, passing a heating current through said articles and said conductor, and completing the weld by pressure. 2. The described method of working metals electrically, consisting in connecting each article with one pole of a generator of electricity, making contact between the ends to be welded and an electrical conductor of equal or less resistance, passing a heating current through said articles and said conductor.

CORRESPONDENCE.

An Elmore Champion.

A Mr. Peck, whose name does not appear to adorn the pages of the Electrician's Directory, and may, therefore, for aught! know to the contrary, be a fishmonger, has sent you copy of a letter (which appeared in your last issue), with which he had honoured the Engineering and Mining Journal of New York. This letter professes to be a reply to some comments I thought it my duty to make in the public interest, on the so-called "Elmore process." I notice that you have numbered the paragraphs in Mr. Peck's letter, as also those of your comments thereon. With your permission I will make a few observations on that contribution, although I confess to being somewhat sick of this Elmore theme.

(1, 2.) Mr. Peck refers to a letter from one Alexander Watt, re the Elmore depositing process." Well, I will reply to 1 Peck, although I consider it somewhat an act of impertinence for a person who acknowledges (paragraph 6) that he does "not profess to know much about the subject" to thrust himself forward as a champion of the "Elmore Companies." Mr. Peck says that my assertion that "the opinion of those who understand the electro-deposition of metals thoroughly, seems to be of an adverse character," is a "deliberate misstatement." Of course it is easy for a person

JUNE 19, 1891.]

who does "not profess to know much about the subject" to accuse those who do of making "deliberate misstatements," especially when the statements happen to be unpalatable. Quite regardless of Mr. Peck, however, I adhere to my statements. Mr. Peck, who does not seem disposed to "hide his light under a bushel "--which would practically extinguish four of his capacity-in paragraph 2, has had the bad taste to drag into this matter the names of several gentlemen, to whom I have never in any way referred in my correspondence on this subject, and he has the audacity to ask whether it does not 66 appear a piece (the exact dimensions of which he does not give) of great presumption on the part of Mr. Watt to dare to create himself judge of such men." Now Mr. Peck's artful, but far too transparent, attempt to give importance to his otherwise silly and uncalled for effusion by dragging in the names of several professional men, with whose views respecting the Elmore process I have no concern whatever, is, I affirm, an act of gross impertinence. But so far as my daring to differ from anyone, if such should unfortunately happen to be the case at any time, upon any subject connected with the electro-deposition of metals, I can assure Mr. Peck I shall not require a license from him.

(3.) Mr. Peck appears to think it remarkable that in writing two separate letters, referring to what I conceive to be inherent defects in the Elmore process, I should have employed two different terms to express my views as to what I believe will be the fate of copper tubes made by this process. Mr. Peck is apparently much exercised in his mind as to the cause of what he is pleased to call my "sudden assumption of modesty" (a quality Mr. Peck, of all persons, should the most appreciate) in using different terms, in different contributions, to express the same meaning. To set his mind at rest upon this point, however, I am quite willing to hold. to the stronger term, which will, perhaps, more fully explain my views, and about which there will be less "weakness or vacillation" to disturb the equilibrium of what Mr. Peck would doubtless consider his mind.

(4, 5.) We are told that Mr. Wm. Elmore is "the father of the inventors, and the managing director of the company." Here we have indeed two refreshing announcements. Mr. Wm. Elmore the "managing director!" Well, we'll see what comes of it. Mr. Peck, however, should be at his elbow, if, indeed, Mr. W. E. did not stand in a similar posé, while Mr. P. (who does "not profess to know much about the subject ") concocted the letter now under consideration.

In reference to Mr. W. Elmore's wager (referred to by Mr. Peck), the conductors of this journal deserve my special thanks for their dignified refusal to degrade their highlyesteemed paper by permitting me (had I felt disposed to bring myself down to such a level) to accept that person's turfy proposal. As to Mr. Peck's contemptible remarks respecting my non-acceptance of the low pot-house method of settling a technical controversy, as proposed by Mr. Wm. Elmore, by a wager, these I leave him to enjoy in company with any person who may have helped him to concoct his

letter.

(6.) Now we come to a really interesting point, but more especially so since it is supposed to be written by a person who says that he does "not know much about the subject." Mr. Peck says "Mr. Watt then tells us that 'metals deposited by electrolysis do not adhere well, if at all, to their kind.' This is news indeed." What! news to a person who professes to know little or nothing-that is "not much "—of the subject! Remember, it is a nice point, Mr. Peck, and none but persons who know something about electro-deposition would be able either to confirm or disprove it. Now, I will be frank with this Mr. Peck, since he has candidly confessed that he does not know much about the subject he has somewhat profusely written upon, and will ask: Did not someone prompt him as to the various technical points contained in this and other paragraphs of his letter? I will not burthen your useful columns by going over the ground again, having already expressed views to which I firmly adhere. As to Mr. Peck's notions concerning my judgment in matters connected with electro-deposition, as expressed in the latter part of this paragraph, I must content myself by expressing my regret that a person who knows so little of the subject should have taken so much trouble to put them in print.

In reference to my opinion that metals do not adhere to polished surfaces, Mr. Peck says he will "take a charitable

799

view," and content himself by "assuming that Mr. Watt has never heard of Mr. A. Smee's theory as to the cause of deposited metals not attaching themselves to the underlying metal." Since Mr. Peck knows so little about the subject, as he tells us, it is not at all surprising that he should wonder if, during half a century's experience in electro-deposition, I had ever taken the trouble to make myself acquainted with works written upon the subject.

(7) In this paragraph we have a kind of addendum for a flaring Elmore prospectus, and since it enters into statements we have no means of verifying, and would certainly not take upon the ipse dixit of Mr. Peck, I will pass it by, and more especially as it has no reference whatever to the defects in the Elmore process I have pointed out, and can only have been introduced as a kind of puff.

(8) Here, however, we come upon matters which require a little more attention-and they shall have it. "Mr. Watt makes the statement that Elmore originally professed to produce his copper tubes from rough copper or matte.' If it is suggested that this statement appeared in the prospectus, I again contradict Mr. Watt." In reply to this, I once more state that Mr. Elmore did originally profess to produce his tubes from copper matte, but I did not say he had stated so in the prospectus referred to, therefore Mr. Peck's contradiction is an unnecessary impertinence. What I did state, however, I will now give my authority for, but I will not favour Mr. Peck-or those for whom he may be acting as mouthpiece, for aught I know-by discussing the sentences quoted from the prospectus, which may be useful for advertising purposes, but are not arguments. Now, as to Mr. Elmore's original professions concerning the material from which his tubes were to be produced. In 1885 Mr. Elmore was negotiating with some gentlemen for the formation of a company to manufacture copper tubes, which he professed to be able to do at £25 per ton. In the case of Elmore v. Pirrie and others, tried before Mr. Justice Kay in November, 1887, in which Mr. Elmore sought to recover £15,000 damages for breach of contract, a letter from Mr. Pirrie to Mr. Barrett (also one of the defendants) was read, from which the following extracts (copied from Mr. Justice Kay's judgment) were taken :-" Elmore and Mr. Cooper have perfectly satisfied me that they can make copper tubes at £25 per ton, as against £59 the present cost." Mr. Pirrie, in his evidence said he asked Mr. Elmore "how can you make copper tubes at less than the cost of copper, taking it at £40 per ton, and you are going to make tubes for £25. He then explained to me that his copper tubes had been made from rough copper or matte (the italics are my own) for which he showed me different invoices for making it at £18 to £20 per ton." This, then, is what Mr. Elmore originally professed not only to be able to do, but to have actually done; whereas now the copper tubes, we are told, are made from Chili bars, at about £53 per ton. If, as "managing director," he could now carry out his original professions, and employ matte at £18 per ton, what an enormous saving that would effect and how his shares would run up! Perhaps he will try, or, on second consideration, perhaps he would rather not!

9. In this concluding paragraph Mr. Peck-"not knowing much about the subject -"thinks he has dealt with all the points in Mr. Watt's letter," and suggests, with the excellent good taste which is so ornamental a feature in the lucubration before us, that "before the slightest heed is given to Mr. Watt's remarks, your readers should satisfy themselves as to his capacity to criticise the Elmore process, as to his knowledge of that process, and as to his bonâ fides." Now as to these three propositions, I will leave myself in the hands of your readers. As to the advisability of a person professing not to know " much" of the subject, entering into technical discussions with all the assurance of an expert, I must leave your readers to form their own judgment, while at the same time they may possibly come to some conclusion as to why, and at whose instigation, Mr. Peck should come forth as champion of the Elmore companies. If my own theory be the correct one, his bona fides in this controversy will, I fear, be open to very grave suspicion.

In conclusion, I may state, for Mr. Peck's edification, that a copy of this letter will be sent forthwith to the Engineering and Mining Journal of New York.

Balham, June 9th 1891.

Alexander Watt.

800

Electricity in Mining Operations.

Having opened the discussion at the recent meeting of The Federated Institute of Mining Engineers, which you subject to a very reasonable amount of criticism, I should like to show yourself and readers that we are not quite the benighted heathen requiring enlightenment which electricians to a large extent assume.

We have in this district shafts 2,000 feet in depth, in which cages with their load weighing 8 tons, run at a speed of 1,300 feet a minute, and we are asked to apply to these an apparatus which depends upon "a few cells, such as Daniells, giving a constant current, and requiring no attention except the adding of a few crystals of Cu, SO, at intervals," to prevent the action of grips, which would instantly stop, like a blow against a stone wall, these enormous moving weights.

I say no; your remedy is infinitely more dangerous than the disease. I have for many years used electricity for telegraphy in my house, in the mines for signalling, for firing shots, and for igniting the gas in a petroleum. engine, and seldom a week passes, that some of them do not fail-they are put right, and no harm is done. But let the battery for the safety catch fail, and terrible results would follow; no guides in the shaft would stand a blow of 10,000 foot tons, but all would go to the bottom together, and, remember, there might be 12 or 16 men in the cage.

You will see, I think, that "this wrong impression" is not on the part of the mining engineers, but of those who wish to persuade them to apply an agent which their own experience has taught them is not suited to the conditions of the case in question.

And now, having finished that part of the subject, at least to my own satisfaction, may I follow your remarks a little further (I always get the ELECTRICAL REVIEW, for I like to know what you are all doing, and saying about us). We are again compared with the wonderful progress made in America in such matters.

But American engineers still come over here and find much in our mines to learn, and I have not met with any who can meet me and prove that upon a single engineering question he is right and I am wrong, in respect of either safety or economy.

I have this week a letter from America (not yet answered) in which the writer says: "Allow me to express my sense of obligations to you for benefits received." And I have another from the same country, in which so much is asked, that I have never been able to find time to reply to it; so that, you may accept my word for it, we are not quite so lost in the mists of antiquity as electricians appear to have persuaded themselves.

Durham, June 13th, 1891.

A. L. Steavenson.

Will you kindly say where I, together with others of your readers who are specially interested in this subject, may find details of the" enormous development" which you allude to in your leading article of the 12th inst.

I was in the United States for several weeks last autumn, and I utterly failed to find, except in one solitary case at a coal mine near Pittsburgh, a single practical application of electricity to any of the numerous purposes you mentioned. There was plenty of talk of what might be done in the near future, and I was shown, in various works, a few more or less promising experimental machines; but after discussing the whole question fully with well informed Americans, I came to the conclusion that the applications of electricity to mining work in England and Wales were far more numerous than those on the whole of the American continent put together. As you allude to compressed air, I may say that I had the advantage of visiting, with some of the leading American engineers, the largest compressed air plants of that country, in iron mines, where everything was done by compressed air; and, although it was thought that the application of electricity in other places might ere long be possible, there was no allusion to the substitution of electricity for air on any such scale as you would seem to indicate in your remarks.

I agree with you that the collection of data would have a good effect in the United Kingdom; and you will be glad to learn that, after hammering away for years, I have at last in

[JUNE 19, 1891.

duced the South Wales Institute of Engineers to appoint a committee to consider the matter. Wm. H. Massey.

June 16th, 1891.

Re❝Electrostatic Inductive Capacity."

I am afraid I was rather vague in my statement that the static capacity of a circuit was increased by the addition of a return wire. What I intended to convey was that the static capacity of an insulated circuit (without a current flowing through it) was increased by the addition of a return wire; or even the theoretical case of an earth connected return system with a current flowing through it. Viewed in this light I may say it is doubled."

The theory I have put before you is equally applicable to looped cables which differ in no essential respect from looped aerial conductors, and without wishing to detract from that theory, which, to my mind, is quite logical and correct, in any way, I think the whole matter may be explained in a few words.

Taking the case of the looped cables. Although as regards static capacity the cables are joined in "cascade" or "series," the sum of the charges (positive and negative) contained on the conductors is equal to the total charge on one of them with earth used, and not to half this charge, as per figs. 1

THE EDISON LAMP SUIT IN AMERICA.

ALTHOUGH the counsel for both sides have finished their argument pro and con, the Hon. W. J. Wallace, the judge of the Circuit Court, who tried the case without a jury, will not deliver his opinion for a week or two yet. This delay will enable the loser by his judgment to make appeal to the Circuit Court of Appeal, a new court which will have been constituted by then. By doing this companies interested will have the option of a double appeal, and undoubtedly it will furnish a larger quantity of work for the lawyers.

Considering the enormous capital at stake, neither party to the suit can rest satisfied until the last legal step has been taken. The complainant Edison Company has a capital of $12,000,000; the various companies which will suffer should the action be decided adversely to the defendants have a combined capital of about three times that amount, of which the Westinghouse interest is estimated at $7,000,000, and the Thomson-Houston at $20,000,000. In addition to these there are several other companies who manufacture incandescent lamps. If the plaintiff gains the day all these concerns will find their power of competing with the Edison Company seriously diminished, while in all likelihood the solvency of the smaller fry will be heavily jeopardised.

In all former trials, especially those relating to the telephone, the actions have been brought before any very large capital has been invested in the business; but in this one, whether purposely or not, the companies have been beguiled, by the delay in bringing the case to a definite issue, into increasing their works and extending their trade far and wide; and now, after more than 11 years from the date of the patent said to be infringed, a blow is struck which, if it answers its intention, will cripple the future trade of the country in incandescent lamps, and will entail endless trouble to the infringing companies in rendering account of their back sales. A plea might easily be raised to alter the law so that, as in other matters, there should be a Statute of Limitations, by which, after a certain time, a plaintiff would be debarred from taking proceedings; this would hasten action. Or,

perhaps, the same purpose would be served equally well by abolishing retrospective damages to a great extent, that is to say, by only allowing the calculations upon which the damages are based to cover a period of one year prior to the date of the commencement of proceedings for infringement of the patent rights.

Unless sentiment prevails with the Courts, it is rather difficult to conceive how it can give to the second claim of the Edison lamp patent so broad a construction as is requisite to cover a modern lamp, for in bringing a suit for infringement it is necessary to base the contest on claims that have been allowed by the Patent Office, and to take into consideration the state of the art at the time. In the M'Keesport case Judge Bradley said: "The claims of the Sawyer-Man patent may be summarised as follows:-1. A conductor of carbon made of fibrous or textile material and of arched form ; 2. A conductor of carbon made of fibrous material in a hermetically sealed chamber without regard to form; 3. The combination of a conductor of carbon made of fibrous or textile material in an arched form in a glass chamber hermetically sealed and deprived of carbon consuming gas. The claim of the combination last named may be dismissed as a separate claim, because a glass chamber hermetically sealed for holding the light has always been used, and must necessarily be used in all incandescing carbon electric lamps; it was used by King in 1845, by Konn in 1872, by Kosloff in 1875, and by others. Unless the patent is valid for the conductor of carbon made of textile. material in an arched form, it cannot be held valid by combining such conductor with a glass chamber hermetically sealed. The arched or bent shape was used by Staite in 1848 for an iridium conductor, and in 1872 it was an arrangement well known in Science and the Arts. Long prior to 1878 it was a well known fact that the transmission of an electric current through a pencil of charcoal interposed in a metallic circuit would produce intense light, and that when this charcoal was guarded from contact with oxygen, in a vacuum or otherwise, it would not be consumed. The great desideratum was to construct an apparatus and to discover a process which would make the light economical and convenient, and of use for

802

ordinary domestic purposes. We are clearly of opinion, therefore, that neither Sawyer and Man nor Edison can maintain any such claim to the exclusive use of charcoal generally in any form as the incandescing conductor in a lamp." The Judge pointed out that it was very clear to him that there was a change of base on the part of Sawyer and Man, the complainants in the case, after the issue of the Edison patent, and that he nullified the claims of Sawyer and Man in consideration of early anticipations and their own modifications after Edison's work on the subject. Judge Bradley said that the great thing described in Edison's patent was the attenuated filament and its enclosure in a perfect vacuum, and that his particular invention made practicable the present incandescent lamp.

This decision appears to be to a considerable extent in favour of Edison as compared with the complainants' patent. Let us turn, now, to the rulings of the Patent Office; these are not always infallible-witness the transformer patent refused to Bernstein, as not possible, and yet in a year or two after issued to another. In 1881 a Mr. W. K. Freeman filed an application for an incandescent lamp, and in an amendment inserted the following claim :-"An electric lamp for giving light by incandescence, consisting of a strip or filament of carbon of high resistance, enclosed within an exhausted receiver made entirely of glass and attached to metal wires passing through and sealed into the glass, as set forth." This application was rejected by the Patent Office, not because it was a palpable repetition of the Edison patent, but for the reason that Crookes's radiometer forestalled the invention. The radiometer referred to is one in which a ring or spiral of platinum is placed in an exhausted globe, and the terminals sealed through the glass. Of course Crookes did not construct it for lighting purposes, but the Patent Office, in refusing Freeman's application, declared :"It is not deemed material that applicant claims a carbon filament in place of the platinum conductor shown in the reference, the substitution one for the other being within the skill of one versed in matters pertaining to electric lighting, it being old in the art to use carbon conductors for incandescent lamps, as shown in King's English patent."

It seems that this reference was not discovered until after the Edison patent had been issued, but the rejection of Freeman's application plainly manifests how difficult it is for an opinion to be formed on any subject, unless the entire history relating thereto be known; and how often, in consequence, an opinion has to be altered when previously unknown facts are brought to light.

It will not be an easy task for Judge Wallace, in his pending decision, to steer an unbiased way through the complicated mass of evidence arrayed before him, and he will find it all the heavier that, looking at the matter broadly, although Edison's claims may not appear impregnably unassailable, still he will feel convinced that without Mr. Edison incandescent lighting would not so soon have become a commercial success.

ELECTRIC RAILWAY SYSTEMS.

A STATEMENT of more than usual interest to electrical engineers appears in the columns of an American journal devoted to railway and tramway matters. In referring to the

66

[JUNE 26, 1891.

greater development in America of electric railways as compared with any other country, our contemporary states: Recently, there seems to be a much greater interest abroad in the electric tramway,' and some firms in this country have received many inquiries in regard to the practical working of such railways in this country. So numerous have they become, that at least one concern here has been led to look into the matter very carefully and to correspond with parties interested. As a result it has come to the conclusion that foreign roads are ready to adopt the system used in this country at once if its advantages are fully explained to them, and it has, therefore, sent a representative to Europe to work up an interest in such matters. This is rather a novel departure, and those who have done so much to make electric railways a success in this country will watch with interest this attempt to extend the same ideas and designs into foreign countries."

This statement is of considerable importance to English and continental firms. That it concerns the United Kingdom equally as well as the continent may safely be assumed from the fact that several gentlemen connected with English tramways have sought information regarding the different systems used and the cost of working them in the United States. One instance was the visit paid to the States some months ago by Mr. W. J. Carruthers-Wain, chairman or managing director of seven English tramways, for the purpose of examining the general working of the lines in that country. It is, of course, only natural that tramway companies should seek for information in the particular country where street electric railways have made so much progress; but the conclusion of the American Company that "foreign roads are ready to adopt the system used in this country at once if its advantages are fully explained to them" is a poor compliment to European systems of electric traction, and if true, it does not imply great faith on the part of our tramway companies in European systems. It must, however, not be forgotten that as far as England, and probably the whole of the United Kingdom, are concerned, the system of overhead conductor so generally adopted in American electric tramway practice is hardly applicable, owing to the Board of Trade regulations, and to the objections of the majority of local authorities to the use of overhead wires. Yet the fact that the representative of an American firm has been sent over to endeavour to introduce American "ideas and designs" brings to mind the questions as to what becomes of European systems, and why the latter cannot be made to answer their purpose in preference to the adoption of transatlantic methods?

During the past four years there have been brought out in the United Kingdom about twelve different systems of electric traction. They have been fully described in the technical journals, they have caused a transitive interchange of compliments between rival inventors, they have been nine day wonders, and then, with the exception of two or three systems being, or about to be, experimented with, they have, as it were, passed out of existence-at least for a time, if not altogether. If financial considerations had not been a sine quâ non, doubtless more would have been heard of each system; but most of them remain in precisely the same position as on their inception, that is to say, on paper. Each of the dozen systems may have been faulty to a certain extent; but notwithstanding this, some of them may be considered as well applicable to the working conditions of