43° Progress in Science. [July, 



once see what is wrong. The instrument has been successfully applied 

 to register the number of revolutions of the screw-shafts of some of our 

 largest steam-vessels, and also to indicate in the editor's room the number of 

 impressions of a newspaper press. 



It is certainly desirable that such an important art-science as Telegraphy 

 should have its representative institution, and the advent of the Society 

 of Telegraph Engineers will be gladly welcomed by the profession. The 

 Society held its first elective meeting on the 31st ult., when Charles W. 

 Siemens, Esq., C.E., F.R.S., was elected President, and Lord Lindsay, and 

 F. J. Scudamore, Esq., Vice-Presidents. Among the Council are Sir Samuel 

 Canning, Professor Foster, B.A., F.R.S., Major Stotherd, R.E., Captain 

 Webber, R.E., Messrs. Cromwell Varley, Willoughby Smith, and Latimer 

 Clark. Mr. Sabine undertakes the two-fold office of Treasurer and Librarian, 

 and Major Bolton is Secretary. The Society is composed, besides its council, 

 of members, associates, and honorary members, to be elected from those only 

 who have been regularly educated as telegraph engineers, or have acquired 

 a degree of eminence in the profession. An annual provincial meeting is 

 to be held in conjunction with the British Association. If talent will ensure a 

 brilliant career, the association certainly promises well. There will be many 

 who will watch its proceedings with great interest ; a helping hand it can 

 hardly want. 



Mr. Joel has lately perfected a galvanometer for measuring the relative 

 intensities of induced currents. The instrument is in principle somewhat 

 analogous to the ballistic pendulum. On the axis of a pair of curved 

 magnetised needles working between two vertical electro-magnets, is rigidly 

 fixed a horizontal arm slightly curved upwards at its extremity. The 

 extremity of the axis acts as a pivot to a slight ivory index loosely centred on 

 an agate cup. By means of a micrometer screw, the index is brought against 

 the curved extremity of the arm. If a current is now passed through 

 the coils the index will be deflected, the arc varying as the intensity. The 

 magnetised needles are arranged so as to register only the first current 

 arriving in the coils. This form of galvanometer is simple, and seems calcu- 

 lated to meet with extended practical application. In connection with 

 an induction coil, it would afford to the medical man a surer indication of the 

 strength of the current he is employing than is at present available. 



A novel adaptation of Sir W. Thomson's reflecting galvanometer has just 

 been made. As is well known, the signals on a cable of high inductive 

 capacity can be transmitted only with extreme slowness and precision, and 

 even then the interpretation of a skilled clerk is necessary. It has been 

 proposed, and tried experimentally with some success, to place at each end of 

 the cable a system of clockwork to cause the synchronous movements of a 

 fugitive dial, upon which are engraved the letters of the alphabet, appearing 

 in succession, as the dial rotates, at an aperture in a fixed screen. On the 

 same screen, a little lower than the aperture, the ray of light is reflected from 

 the mirror of the galvanometer. The clerks at both stations, by pre-arranged 

 signals, set their clockwork in motion at the same instant, the receiving clerk 

 watching the dial and the light. The transmitting clerk, also watching his 

 dial, immediately on the arrival of the letter required at the aperture, depresses 

 a key, causing a deflection of the light at the distant station. Seeing this 

 deflection, the receiving clerk immediately calls out the letter appearing at that 

 instant on the dial to his assistant. According to experiments made on an 

 artificial cable of extremely high inductive capacity, the rate of signals 

 attained a maximum of 25 words per minute. Other advantages of the 

 system are — that equal and opposite currents can be sent to line, and but a 

 small battery power employed. A further modification is the substitution of 

 type-wheels moving synchronously for the dials. Upon perceiving the 

 deflection of the light the receiving clerk depresses a key, which causes a paper 

 slip to be raised against the letter immediately opposite on the type-wheel. 

 The difficulty of obtaining the perfect synchronism of the dials or type-wheels, 



