February ii, 1909] 



NA TURE 



441 



supposed that the single-phase system is untried. There 

 are in Europe more than thirty different railways, portions 

 of which are now in operation or under construction by 

 single-phase current, aggregating in all more than 850 

 miles, while in America there are nearly 1000 miles of 

 railways being so operated. Some of these, however, are 

 not heavy electric railways, but interurban electric rail- 

 ways laid' down for electric working from the start. Hence 

 before long it should be possible to obtain ample experi- 

 ence of the results of single-phase working. Some of these 

 svstems are of considerable length. Thus the Prussian 

 State Railway will have 112 miles electrically worked, 

 while the Berlin Stadt and Ring Railway will have 366 

 miles, and in America the Spokane Inland Railway Com- 

 pany has 115 miles. 



Choice of System. 



Many engineers and railway men have unfortunately 

 adopted an attitude of partisanship on this, a question 

 which should be considered primarily on its merits in each 

 particular case. It is quite absurd to generalise and say 

 that the single-phase or the direct-current system is the 

 better. Each has its own field, each is excellent and 

 desirable under its own set of conditions, and only those 

 who have studied all the conditions in each particular case 

 con say which is the best scheme to adopt financially. 



.■\s regards main-line working pure and simple, engineers 

 have not yet decided quite as to the best systems of doing 

 it, neither are railway men entirely satisfied as to the 

 financial advisability of converting main-line working ; but 

 for heavy working under special conditions electrification 

 is being more and more considered. Thus the Grand 

 Trunk Railway has recently equipped the St. Clair Tunnel 

 for electric working, an installation which is notable as 

 being the heaviest railway service in the world handled 

 by electricity. Trains weighing 1000 tons are hauled from 

 one end of the tunnel to the other, about two miles, at a 

 minimum speed of ten miles per hour on a gradient of i 

 in 50. The new tunnels under the Hudson River at New 

 York, by which the Pennsylvania Company will obtain 

 access to Manhattan Island itself, are also being electrically 

 equipped for the haulage of main-line Pennsylvania trains, 

 which are naturally of great weight. A project of a some- 

 what similar character is that which the Great Northern 

 Railroad of America is considering in connection with the 

 electrification of a new section of line over the Rockies, 

 where the three-phase svstem, which has been a good deal 

 used in Italy and Switzerland, is likely to be adopted. 



Thus it will be seen that there is plenty being done in 

 electrification work. It is to be regretted, however, that 

 actual financial results, especially operating costs, have 

 been very sparingly published. While it is known that 

 the North-Eastern Railway Company, for instance, has 

 been well satisfied with the results of the traffic obtained 

 on its Tynemouth lines, and while the traffics on the 

 District and Metropolitan Railways are now beginning to 

 show steady improvement as the result of electrification, 

 the actual balance-sheet of expenses and receipts has not 

 been made public. .A number of preliminary figures re- 

 garding the New York Central lines have been published, 

 but they were hardly complete enough and the result of too 

 recent work to be of much value. While as regards 

 engineering experience tliere is a free interchange of ideas 

 between the different makers and the various engineers 

 concerned, there is less of this as regards traffic receipts. 



It is to be hoped that ere long it will be possible 

 for those responsible for the management of lines which 

 are being electrically worked in this country to make 

 public some of the results they have obtained for the 

 benefit of those who are still considering the question. 



THE TELEGRAPHIC TRANSMISSION OF 

 WRITING. 

 'X'HE advent of the telewriter should obviate the mis- 

 takes and misunderstandings which so commonly 

 occur in business messages transmitted by telephone, and 

 should save the repetition work now necessary owing to 

 messages having to be confirmed by letter. 



The telewriter consists of a transmitter and receiver. 

 The message to be sent is written in pencil on a roll of 



NO. 2050, YOL. 79] 



paper attached to the transmitter, and is exactly repro- 

 duced in pen and ink on the distant receiver. The pencil 

 at the transmitter is fixed at the junction of two jointed 

 rods, which are connected to each of two shafts, and 

 communicate a rotary movement to them. These shafts in 

 turn inove contact pieces, which cause a variation of voltage 

 in two electrical circuits. These circuits control two 

 moving coils suspended in an electromagnetic field in the 

 receiver, and the jointed rods connected to these coils 

 actuate the pen which reproduces the writing — or message 

 — on a roll of paper at the receiver. 



Thus anv motion of the pencil at the transmitte.- is re- 

 solved into two component movements, which cause a 

 variation of the positions of the moving coils at the 

 receiver. These coils, actuating the two levers to which 

 the receiving pen is attached, reproduce the motions of 

 the pencil at the transmitter. 



When the paper available for writing on at the trans- 

 mitter has been used up, it is fed forward mechanically 

 by pulling a lever, which at thr s.mio time causes ai 



od Receiv 

 Departmental Exchange. 



current to be sent through both lines and operates a relay 

 which actuates the paper in the receiver proportionately. 



Before starting to send a message, a button is pressed 

 on the transmitter, and this automatically ensures the 

 lever at u\e receiving end being in the proper position for 

 the instrument to receive a message. The receiving pen — 

 before contact is made by the pencil on the transmitter — 

 reposes in an ink-well, and this ensures that plenty of ink 

 is always obtainable. The telewriter is also fitted with 

 a telephone, and communication can be held by either 

 method over the same lines, but not simultaneously. 



.An advantage of the telewriter over the telephone is 

 that, should the person rung up be out, the message can 

 be written and will await his return. No operator is 

 necessarv to receive the messages, and so long as the roll 

 of paper in the receiver lasts, so long can messages be 

 received. 



The ordinary telephone wires are all that is necessary 

 for the operation of the telewriter, the power being 



