588 



NATURE 



[Oct. 20, 1 88 1 



mitters, and the circuits for the others are arranged on 

 the same plan. A little study of this figure is enough to 

 show that in each pair of telephones in the receiving 

 room the left one corresponds to the transmitters on the 

 left side of the stage, and the right one to the transmitters 

 on the right side. All the left-hand telephones are in one 

 circuit, and all the right-hand ones in the other. This 

 arrangemen', which is clearly shown in the figure, is very 

 ingenious, and though a simpler arrangement with a 

 smaller number of circuits could have been employed, 

 the additional expense involved in having so many cir- 

 cuits was not allowed to stand in the way, as it was 

 necessary in order to make forty-two pairs of telephones 

 work properly ; and even this number is not sufficient to 

 satisfy the public curiosity. 



These brilliant experiments show that there was no 

 exaggeration in the statements which were publish' d 

 soon after the invention of the telephone, to the effect 

 that concerts and sermons had been heard at great 

 distances. It cannot now be said that we were too 

 credulous when we announced in 1S78 that the opera 



Fig. 4. — Ader's telephone ^ suiLjccitation. 



"Don Pasquale " had been ver) well heard in the telephone 

 at Bellinzona, pnd that no e of the fine turns of this 

 charming music had been lost. We believe mdeed that 

 the results then ob;ained were far inferior to those which 

 we have now the opportunity of enjoying; and still more 

 marvellous results in telephony have, we are informed, 

 been quite recently obiained. 



Fig. 3 represents one of the hearing rooms, namely, 

 that which is lighted with Lane-Fox lamps. A mahogany 

 wainscotting is carried round the walls at about the 

 height of the ear, and on it are fixed tventy small wooden 

 panels furni-hed with hooks to hang the telephones on. 

 The telephones are connected with the underground con- 

 ductors by means of flexible wire cords which con^e out 

 of the wainscotting, so that nothing is easier than for the 

 auditors to put the telephones to their ears. As the 

 telephones are connected, eight in each series, with one 

 and the same pair of microphonic transmitters, and the 

 different pairs of transmitters occupy different positions 

 on the stage, the effects are not ihe same for all the tele- 

 phones. Those which are in connection with transmitters 

 at the extreme right or left are more affected by the sounds 



of the loud instruments in the orchestra than those which 

 are connected with the transmitters nearest the prompter ; 

 but thcie latter, on the other hand, are more affected by 

 the prompter's voice. 



To make the effects as equal as possible, M. Ader has 

 so arranged the connections that the two transmitters 

 which form one pair are in precisely opposite conditions ; 

 for instance, the transmitter at the extreme left is paired 

 with the first to the right hand of the prompter, the 

 second from the extreme left with the second to the right 

 of the prompter, and so on. The beat effect is obtained 

 from the pair which occupy the middle places in the two 

 sets. These differences give an obvious e.vpbnation of 

 the different accounts given by different persons of the 

 predominating sounds which they have heard, and explain 

 why many of them, having heard in different parts of the 

 same room, have not received the same impressions. 

 Naturally enough they attribute the difference to the 

 quality of the telephones, but though it is possible that 

 some of these may be better than others, it is to the 

 positions of the transmitters on the stage that the differ- 

 ences are chiefly attributable. 



[The receiving instrument, which, as above stated, is 

 the It'lepJwne a surexcitation of M. Ader (pronounced like 

 the English name Adair), is very similar to the Gower- 

 Bell r&eiver, having like it a steel horseshoe magnet, 

 which forms nearly a complete ring, and which, being 

 coated with nickel, serves as the handle. Round the two 

 soft iron pole-pieces of this magnet coils of very fine wire 

 are wound, which are in circuit with the line wires, so 

 that the currents from the transmitter at the sending- 

 stalion pass through them. A thin circular plate of iron, 

 fastened by its edges, is fixed at a very small distance 

 from the pole-pieces, and serves as the vibrating dia- 

 phragm. The peculiarity of the Ader telephone is that a 

 flat ring of soft iron is fixed at a little distance behind 

 this vibrating plate ; that is to say, on the side remote 

 from the magnet, its office being to concentrate and 

 intensify the force of the magnet upon the diaphragm. 

 This is what is meant by surexiitation. The plate, in 

 fact, is more strongly attracted by the magnet than it 

 would be if this ring «ere absent. In Fig. 4 (which con- 

 sists of three sections and one elevation of this telephone) 

 A is the steel magnet, B IJ are the coils, M M is the vibrat- 

 ing diaphragm, X X the flat ring for intensifying the 

 force of the magnet upon the diaphragm, O the resonance 

 chamber, and E the trumpet-shaped opening which is 

 applied to the ear.] 



The following account of Rysselberghe's meteorograph 

 was accidentally omitted from a previous article : — 



One of the neatest specimens of electric.il mechanism 

 is the raetcorogiaph of M. Van Rysselberghe, exhibited 

 by the Royal Observatory of Brussels. It gives its 

 records not only at the place of observation, but at one 

 or more distant stations, and is now giving every night. at 

 Paris a record of the indications of the instruments at 

 Brussels, t nee every ten minutes it comes into action 

 and registers one after ihe other the six following ele- 

 ments :— (l ) temperature ; (2) humidity ; (3) water in rain- 

 gauge : (4) direction of wind ; (5) baron^eter ; (6) velocity 

 of wind. It also makes a mark about every half second 

 due to the action of clockwork at the sending-station. 



The registration is made by a diamond point on a thin 

 plite of zinc which is bent round the surface of a revolving 

 cylinder, and which is covered with lamp-black to male 

 the marks more \isible. This plate serves afterwards for 

 printing any number of copies. There may be several 

 of the e cylinders at as many different stations, all receiv- 

 ing simultaneously the indications furnished by any one 

 station. The mode of action is as follows : — 



Let us tal e for example the case of one of the thermo- 

 meters. The thermometer-tube is vertical and open at 

 the top. A long metallic probe smaller than the tube of 

 the thermometer descends once in ten minutes with a 



