Wheatstone, and Morse, were scientific enthusiasts-that telephones are because Reiss, Varley, Bell, Edison, and Hughes were covetous of fame, fortune, or notoriety.

No! Railways and steamers, telegraphs and telephones, are means adopted by the Great Designer to meet the needs of growing populations-to render possible the feeding and clothing of the ever-increasing millions—to lay under contribution for their benefit the uttermost parts of the earth. They make the world larger by increasing its capacity for population, and, at the same time, smaller by quickening communication. The means at the command of our fathers a hundred years ago would not suffice to feed the populace of to-day. Famine and pestilence, without such beneficent provisions, would have kept back the multiplication of the human race; a certain stage would have been reached, but, without the new appliances, never passed. The process is still going on, and will not stop at telephones we may be sure. The future has greater wonders in store than any we have so far seen. Some are already casting intermittent scintillations of their brilliance before-just as telegraphs and telephones were talked of ages ago. It has been truly said that the dreams and fairy tales of one generation become the everyday commonplaces of the next.

Starting with the admission that the telephone is neither a fad nor a luxury, but a providential provision for man's use and benefit-a practical, earnest, matter-of-fact instrument, which has come to stay-we may likewise assume that it is not possible to stifle it, to relegate it to oblivion, or even to curtail its natural extension. Sooner or later it will be universally recognised that the general use of the telephone has to be provided for, and the legislative sanction I am now advocating will be granted in order that such an excellent servant may be turned to the best account.

Without such legislative assistance, which, I contend, cannot consistently be withheld, seeing that it is granted as a matter of course to railway, tramway, and other companies, the efficient and economical telephoning of great cities verges so near to the impossible that, during the remainder of my paper, I shall assume that it will be forthcoming at the proper time.

As already indicated, the system of the future for all large towns must be founded upon the use of multiple switchrooms, each serving its own immediate neighbourhood.

All the subscribers' lines will then be short and economical to construct, while the switching apparatus, owing to sub-division, will be simple and cheap. These conditions will enable the annual payments by subscribers to be kept down to a minimum.

All subscribers' lines will be metallic circuits. To the British Post Office (in the person of Mr. W. H. Preece) belongs the honour of being the first to insist on the necessity of double wires for telephone exchanges. The Post Office exchanges have always been constructed on that plan, and, until a few months ago, they were singular in that respect, and the only o os in Great Britain to which a British technical man could rer with any gratification. Some of the National Telephone Company's exchanges have not been without merit, but being single-wire ones, their foundations were as quicksand, and no amount of ingenuity expended on the superstructures could compensate for such a radical defect At best, the faults inherent in the system could be palliated, not cured.

So long ago as 1883 I warned the National Telephone Company of the error they were committing in persisting in the use of the single-wire system, and pointed out how it was then possible to change gradually and economically to metallic circuits. opportunity was lost, and now cannot be regained without sacrificing the greater part of the capital they have expended.

The

When the Mutual Telephone Company started in Manchester I advised them to have nothing to do with single wires, but to secure privacy and freedom from disturbing noises by using nothing but metallic circuits. The advice was taken, and universal commendation has resulted.

To obtain an efficient service with multiple switchrooms by the aid of the switching apparatus ordinarily used in this country, with its intermediate electromagnets and numerous complications, would be out of the question. A radical departure from existing practice must be made in this, as in other particulars. Fortunately, the way out of the difficulty lies ready to our hand.

For a good many years now a system known as the "Mann " has been operated with the greatest possible success in several districts, principally in Scotland. This system is unrivalled in many respects. It enables connections to be obtained with certainty and celerity; it renders easy the task- on some of the older exchanges an arduous and frequently impossible one-of getting rid of one connection and obtaining another. It simplifies and cheapens switching apparatus to an almost incredible degree, and it permits of connections being made through many switchrooms without the intervention of intermediate electromagnets, so that no retardation and indistinctness of speech results. The system possesses other conspicuous merits, but it is unnecessary to enlarge on them here.

In one respect and in one only-is the "Mann" system apparently more complicated and more expensive to instal than the ordinary. It necessitates the taking into each subscriber's office of a branch from a common service wire, on which all communications with the operators are conducted, and the addition to each subscriber's instrument of an extra piece of apparatus.

But the complication is more imaginary than real, while the extra cost of the service wire and fittings is saved many times over in the switch room, where an infinity of complicated and expensive apparatus is dispensed with, and where faults, and attendance by skilled electricians, are reduced to a minimum.

The main feature of the system is the service wire already mentioned. One such wire is allotted to every 60 to 100 sub

scribers, according to the amount of traffic passing. During the busy hours of the day operators are always listening on the service wires, so that subscribers may speak and be heard without any premonitory signals. By means of specially-constructed telephones, weighing but a little over 2oz., attached to the head by springs, the girls are enabled to listen continuously without fatigue, and at the same time keep both hands free for operating purposes. The subscriber, on his part, can at any moment place himself in communication with the operator by depressing a small lever, which has the effect of changing his instrument temporarily from his main line to the service wire.

The mere depression of the lever suffices to secure her attention at any moment, so that mistakes can immediately be rectified and an explanation asked of any delay. The operators have not to do any ringing at the exchange, the subscribers working their own call-bells, thus leaving the girls to perform only the acts of connecting and disconnecting, a feature which greatly contributes to the rapidity for which the system is famed. A deal of labour is also saved by the absence of the ordinary shutter indicators, the putting up of which, after they have been dropped by the subscribers, constitutes a large part of the operator's work with other systems. The general plan of the service wire is shown in Diagram I. The operator's phone is always earthed; those of the subscribers only when their levers are depressed.

During the night and slack hours the operators do not listen continually, but the depressing of the subscriber's lever makes a signal which the operator can respond to so quickly that she is ready to listen as soon as the subscriber is to speak.

The marked superiority which this system had shown over every other in Scotland during the years 1883-90, induced the Mutual Telephone Company to adopt it for their Manchester exchange. It was accordingly introduced there in February last, and has already established itself firmly as the best in the estimation of the subscribers.

The experience gained at Manchester has enabled the one objection to the "Mann" system-the necessity of taking an additional wire into each subscriber's office-to be overcome.

After having designed and partially constructed the Manchester Mutual Exchange on the "Mann" system, it occurred to me that it might be possible to convey the service messages between subscribers and operators by means of electrostatic induction between the subscriber's metallic loop and a special single wire run out for a sufficient distance from the exchange amongst each group of metallic circuits.

On arranging the wires and apparatus in the manner indicated in Diagram IV., it was found that such a plan was really practicable. The connections of the subscriber's instrument were altered in such a way that on depressing the lever the metallic circuit (represented by M in the diagram) was put to earth through the telephone. The metallic circuit then acted as a single wire of double area, and whether insulated at the switchboard or connected through to another circuit practically formed one plate of a condenser, the other plate or plates of which were any of the adjacent wires that happened to be earthed at their extremities. It was therefore only necessary to put the operator's instrument in permanent connection with one or more wires running parallel to the subscriber's metallic circuit for a short distance, to enable any of the subscribers, whose instruments were so fitted, to communicate with the operator by depressing their levers. When the

include the chief of the telephonic wealth of the metropolis. Such portions as lie beyond are comparatively poor, and can be dealt with readily by special offshoots from the main system. Comprising, as it does, the heart of London, such an area would contain the whole, suburbs and all, of any other city in the world. My remarks apply, therefore, to any large town, and the scheme curtailed will fit any town smaller than London.

In considering my plan I have kept steadily in view the conditions I have stated to be indispensable, putting efficiency first and economy second, although, as it happens, I have found the two march well together; so that the working out of my plan, especially if permission to place wires underground is obtained, will be found quite compatible with earning a good dividend on £8 rates. With the Mutual system vanishes the whole costly and complicated paraphernalia of American switchroom apparatus which has been so blindly copied in this country. As an instance of the economy effected, I may mention that in a switchroom titted for 5,000 subscribers the first cost per subscriber on the American plan is about £3. 10s. for switching apparatus alone; on the Mutual plan adopted at Manchester, the cost per subscriber is about 10s. The difference in cost of maintenance is even more striking, while the efficiency is altogether in favour of the cheaper method.

On the American plan each 100 subscribers occupy 9.9 square feet on the switchboard; on the Mutual plan, the space required for 100 is exactly 54in. square. An American switchboard for 5,000 subscribers is 162.5ft. long, and it occupies 325 square feet of floor space. A Mutual board of the same capacity is 44ft. 10 in. long, and occupies 104 7 square feet of floor space. A Mutual board, consequently, costs about one-seventh, and occupies less than onethird of the space of an American. The matter of privacy has been so specially studied that with the Mutual switchboard the operators cannot "tap "-that is, listen to conversation between subscribers-an operation which, with American boards, can be performed continually and continuously without the subscribers being any the wiser.

As already indicated, I propose to telephone any large town by dividing it into sections about a square mile in area. It will not be possible to adhere rigidly to such a division in practice, as parks, rivers, and open spaces will often intervene, and in very active commercial quarters, like the City of London, smaller sections, perhaps as many as four to the square mile, would no doubt be found desirable; but an approximation to the plan will always be possible, and allowances such as these can be made without departing from the principle.

In the centre of each square I would place a switchroom, making thirty-two sectional or branch switchrooms in an area of thirtytwo square miles.

According to the configuration and general requirements of the town, I would establish one central switchroom, as in Diagram II.; or two such rooms, as in Diagram III.

This would give thirty-three or thirty-four switchrooms, as the case may be, for the town.

The subscribers in each section would be connected, each by a metallic circuit, to their appropriate switchroom, and the sectional switchrooms would, in their turn, be connected to the central rooms by as many metallic circuits as the traffic passing through them may be found to require. These metallic circuits, joining the sectional switchrooms to the central, I call junctions. When two centrals are used, as in Diagram III., they are connected together by additional junctions. In addition to the junctions, there would be, between the switchrooms, a sufficient number of service wires-that is to say, metallic circuits reserved entirely for service communications between the operators.

The mode of operation may be either the "Mann" plan pure and simple, or the modification of it which I have described. The latter would be the more economical, as it saves a wire to each subscriber.

At the sectional switchrooms, operators would always, during busy hours, be listening on the service wires for orders from subscribers, or from the central; at the central, operators would similarly be listening for orders from the sectional operators.

The subscribers' lines could be distinguished, as is usual, by numbers, each sectional switchroom having assigned to it 5,000 numbers, the first room having numbers 1 to 5,000; the second, numbers 5,001 to 10,000; so on to the thirty-second, which would accommodate numbers 155,001 to 160,000. This would give a skeleton list more than sufficient for one telephone to 50 inhabitants, and would take a good many years to fill up. Further expansion than this we may safely leave to our children to deal with, but the placing of new switchrooms midway between the old suggests itself as an appropriate method of meeting any demand in excess of the capacity of the square-mile scheme. Subscribers object most strenuously to any change in the number they have been accustomed to, and the necessity of making such changes can only be provided against by adopting a comprehensive scheme to begin with. The use of very high numbers could be avoided by assigning each switchroom a distinguishing name or code-word, and numbering its subscribers from one upwards.

The junctions between switchrooms would also be known by numbers prefixed by a name, or code-word, which should preferably be of one, or at most two, syllables, since it would have to be repeated thousands of times a day, and indicate the locality of the section-such as, Chelsea, 1, 2, 3, etc.; Tower, 1, 2, 3, etc. Sections that cannot be indicated well in a short word may be known by the names of colours-red, blue, etc.

The central switchroom need not be exclusively reserved for operating junctions. It would probably be found advantageous to connect direct to it subscribers in its immediate vicinity, and for these a separate switchboard could be provided.

per cent. cf junctions. I apprehend no difficulty whatever in arranging 40,000 lines in one room. The floor space required would only be about twice that now wanted for 5,000 lines on the American plan.

The rent and other expenses of so many switchrooms may be urged as an objection, but I do not consider it at all a serious one. Small apartments would suffice for the sectional rooms; many of them would be in cheap neighbourhoods, and all could be top floors or attics.

It may also be said that the number of operators required would be great; but so it would be with any system, and the wages of a few score of girls are neither here nor there when the economies otherwise effected, and the prize to be won by any company giving a good and cheap service in such a town as London are considered.

Such a service would, I believe, produce a circle of between 30,000 and 40,000 subscribers in the course of three or four years. But supposing that London only managed to attain the present level of Galashiels within that period, the number would be 28,000. This, at £8, would mean a gross annual revenue of £224,000, and, deducting 50 per cent. for working expenses, a Det revenue of £112,000. Capitalised at 5 per cent., the sum represented would be £2,240,000, or £80 for each subscriber connected. How such an amount could be expended I cannot imagine. With a switchroom in the centre, or nearly so, of every square mile, the average length of the subscribers' lines would be only a quarter of a mile. The cost of wires, instruments, and switchroom fittings would be £10 per subscriber at the outside. Debiting each subscriber with another £10 as his share of the cost of the junction lines and central, there would remain a balance of £60 per subscriber for conduits, labour, and miscellanous expenses. I repeat that I do not know how such a sum could be spent, and I believe that after a short experience a subscription of £8 would be found unnecessarily high, and capable of substantial reduction. But to ensure such a result, the systematic working out of a definite plan must be insisted upon. There must be no patching of patches, and the first object of the undertakers must not be to make money by hook or by crook, but to establish an efficient exchange. That done, the rest will follow of its own accord, and the reward will be rich exceedingly.

Mr. Preece has shown us how efficient telephonic communication can be established with Paris and other distant towns; and one consequence of the adoption of such a system as I have described would be that London subscribers would be able to speak from their own offices and houses to the offices and houses of subscribers in Paris. The adoption of metallic circuits in Brussels and many other continental towns would bring them also within range. Without metallic circuits the scope of long-distance telephoning is restricted within much narrower limits; for instance, London subscribers cannot at present speak to those in Manchester or Liverpool, except by the aid of special apparatus corresponding to that which I would make universal.

The success of the Mutual Telephone Company in Manchester may be cited as an instance of what is possible with low rates and a good service. The rate is £5 to shareholders, and £6 to others, and the average is very nearly £5. 10s. The exchange commenced working on February 28th last with 68 subscribers. On June 30th there were 413 subscribers connected, and the net profit on the month's working for Manchester centre was at the rate of 4.64 per cent. per annum; on July 31st the number connected was 506, representing a revenue of £2,840, and the profit on the month's working was at the rate of 504 per cent. per annum. the same date the amount expended on the Manchester exchange was £12,469, scarcely £24. 128. per subscriber, which sum not only represented the cost of joining up the 506 subscribers, but included provision for future developments on an exceedingly liberal scale.

At

I think, therefore, that there is reason to believe that telephony may be both good and cheap at the same time, and that in the future it will be both.

APPENDIX.

On an existing exchange worked according to Mann's system, each operator in ordinary course of business deals with 180 connections per hour, or exactly three per minute, of which about half have to be obtained from, or given to, operators at other switchrooms. On a special trial being made, by several inspectors being put on an operators' service wire, with instructions to supplement the ordinary traffic by demanding connections incessantly, the operator successfully dealt with 357 connections in exactly one hour. She therefore got through 5'95 per minute for 60 consecu. tive minutes, which gives an average for each connection, including subsequent disconnections, of 10:09 seconds. Of these she completed 92 herself, 223 had to be asked from another switchroom, and 42 were given to another switchroom. All the usual incidental work was properly performed, such as informing callers that the subscriber wanted was engaged ringing up callers, and notifying that the subscriber previously advised as engaged could now be had; answering repeated demands from impatient callers for engaged or dilatory subscribers; informing operators at other switchrooms that subscribers wanted could not be had, with the reasons, and subsequently advising that they were free.

Special tests were made to ascertain the rate at which connections involving the attention of three different operators (corresponding to Class III. of the proposed London system) could be completed and subsequently got rid of. For this purpose a model conversation was arranged, each subscriber on being rung up being told: "This is the telephone manager's office; is there one of my inspectors at your place just now?" Two tests were made, in each case 20 consecutive connections being demanded

It

with subscribers taken at random from the list, except that only those were selected whose connections, owing to the position of their premises, would have to be handled by three operators. was agreed beforehand, that if any subscriber called for left his bell unanswered for 60 seconds the experimenter would tell the operator to disconnect and give another. The tests took place during busy hours of the day, and were imposed on the ordinary traffic.

Test A.-Twenty connections were made, but the twelfth subscriber asked for did not answer within the regulation minute, so that only 19 model conversations were held. The first connection was asked at 10h. 1m., and the twentieth was done with at 10h. 19m. 40s. Deducting one minute lost over the subscriber not obtained, the average for the 19 conversations had was 55'8 seconds. Test B.-Twenty connections were asked for, but one subscriber was engaged, and two others did not answer within the regulation minute; consequently only 17 model conversations were held. The first connection was asked at noon precisely, and the twentieth was done with at 12h. 14m. 20s. Deducting three minutes lost over the three not obtained, 17 conversations were completed in 11m. 20s., giving an average of 40 seconds per conversation. Of the 680 seconds occupied, only 136 were taken up in asking for and making the connections; the balance was consumed in ringing the subscribers called, by their delay in answering, in putting the model question, and receiving the replies which were not always confined to a monosyllabic negative.

ERRATUM.-In Mr. Preece's paper on "The London-Paris Telephone," published in our last issue, in the last paragraph-page 212-the figures 18 and 3 should read 18 and 3.-ED. E. E.

DISCUSSION ON THE PAPERS OF MR. PREECE AND MR. BENNETT. heard from Mr. Preece they were at a disadvantage, because the Major-General Webber said that in such a paper as they had reader was naturally tied down by his official position, and did not give to himself or those with whom he was associatedthey being public officers-all the credit that they deserved. No doubt many of those present had watched what had been called long-distance telephony, as accounts came out in the public press from year to year. They had seen reports of experiments that had been made between Paris and Brussels, associated with names which he need not mention there; and perhaps they had wondered that during so long a period no great success in establishing long-distance telephony had been achieved at an earlier date. It was owing to Mr. Preece and to those connected officially with the telegraph departments of Great Britain and France, assisted by that great factor the public purse of both countries, that long-distance telephony had been made a success; and that chiefly for the reason that those gentlemen early saw that it was necessary to have a metallic return. Those who investigated the subject in previous years had in view the utilising of existing telegraph lines, all of which had earth returns, and all their efforts were in that direction. The credit of showing that a metallic return was necessary was due to their chief electrician, as also was the inducing of those who had charge of the public purse strings to incur the necessary expenditure to enable it to be done in the way in which Mr. Preece had described. The achievement which Mr. Preece had described was one of the most marvellous public works of this kind that had been undertaken in he was sorry it had not been read in extenso as it deserved. He also this country and in this century. As regarded Mr. Bennett's paper, thought that a great many present had not been able to realise the value of what he had brought before them. He had described the Mann system of telephone exchanges, or rather he would have done so if he had had time. The whole question was one that was very much before the introducers of the telephone in this country in 1880. At that time the advantage of a metallic return was well known. But it was a serious question to those who had to find capital for the establishment of telephone exchanges in the towns of Europe to incur the cost of two wires to every subscriber. The cost of one wire was, say, £10 per mile, and the doubling of that for a large system meant a very considerable outlay. He must admit that, being largely interested in that establishment, when he had to give his vote he gave it in favour of one wire and earth returns. The effect of induction and other difficulties had since brought about the conclusion that the double wire was the best. He thought this was the natural result of experience, and he was glad to see that people were going to use this system. third wire, not a third wire to every subscriber, but one between, But they must also recollect that the Mann system necessitated a say, 50 or 60 subscribers; and, therefore, increased expenditure per subscriber was necessary in the shape of capital outlay on lines. While the application admitted at once of the simplification of the increased. The really interesting point in Mr. Bennett's paper exchange room, the complication of lines was to a certain extent was the discovery-he believed he was right in calling it his (Mr. Bennett's) discovery-that had been pointed out to them in Diagram IV. It was a most interesting outcome of his investigations and experience, because, admitting that the Mann system was the best, this saving in a branch wire into every subscriber's office was an important factor in the success of the scheme. But Mr. Bennett did not give credit to one essential feature of the system he (the speaker) advocated in 1883, at the Society of Arts. He pointed out that the great delay in telephone exchanges was due to a system which had been brought to this country by persons who

* Mr. Preece's paper on "The London-Paris Telephone Line"

was given in our last issue.