586 



NATURE 



[Oct. 20, 1 88 1 



himself, and is, wo believe, the best account yet published. 

 Our own additions are in square brackets. 



One of the greatest successes of the Exhibition of 

 Electricity is certainly the arrangement for the telephonic 

 hearing of theatrical performances which has been or- 

 ganised by the Socidt($ G^ndrale des Tdldphones. By 

 means of an electrical connection which has been esta- 

 blished between the Opera, the Theatre Frangais, and 

 the Exhibition Palace, it has become possible to hear in 

 tbe most complete manner the pieces played on our two 

 principal dramatic stages. The singing of the Opera 

 especially has a fairy-like effect, and all who have been so 

 fortunate as to penetrate into the sanctuaries reserved for 

 these hearings go away astonished and enchanted as if 

 they had come from a dream of the Thousand and One 

 Nights. The effect is in fact captivating ; for the singing 

 of the Opera is positively better heard in this way than in 

 tlie Opera House itself; the words are more distinct, and 

 the delicate turns of sound are better rendered, in conse- 

 quence doubtless of the fact that the telephonic trans- 

 mitters, being interposed between the actors and the 

 orchestra, the instrumental music is to some extent sacri- 

 ficed to the singing. It would scarcely be an exaggeration 



Fig. I. — Stereoscopic 



to say that we hear too well, for the words of the prompter 

 are heard with a distinctness which is somewhat distract- 

 ing. In short the success is com] lete, and the Socicte 

 des T^Mphoncs, as well as M. Ader, who has superintended 

 the arrangements, have a large claim on public gratitude. 



The theatrical performances are to be heard not only 

 in the four rooms allotted to the public, but also in a little 

 boudoir off the so-called Salon de I'lmperatrice, which is 

 at some distance from the others. Here there are no 

 external noises to distract, and it is possible to enjoy the 

 charming melodies at one's ease. 



The four public rooms, one of which is represented in 

 Fig. 3, are covered on ail sides with drapery to deaden 

 external sounds, and the telephones are hung in pairs 

 from wooden panels, of which there are twenty in each 

 room. Chandeliers supporting lamps of .Swan, Maxim, 

 and Lane-Fox light each of these rooms, and the entrance 

 to each is through a kind of pen which holds twenty 

 persons in single file. The auditor has only to put the 

 two telephones to his ears to hear the theatrical per- 

 formance. On the table in the centre of the room there 

 is a telephone for the use of the officials. 



The connecting wires pass across the northern portion 

 of the galleries of the Exhibition, and thence through 

 sewer pipes to the Opera House and Theatre Frangais, 

 where they abut on the stage of each of these theatres, 

 and terminate in transmitters, which are in fact micro- 

 phones with multiple contacts. Those which are em- 

 ployed are of the Ader system, and are the same as those 

 which are used for the Telephonic Exchange of Paris, 

 but with one slight modification to meet the exigencies of 

 this special purpose. As is well known, the acting por- 

 tion in these transmitters consists of a sort of gridiron 

 composed of two fixed parallel bars of carbon loosely 

 connected by means of six sijialler cross-bars of the same 

 material, whose ends are supported by resting in holes in 

 the sides of the large bars, and are free to rattle about in 

 them. This frame of carbons is attached in a horizontal 

 position to the under side of a thin board of pine, which 

 is the vibrating plate. [Sometimes the gridiron is doubled, 

 so as to consist of three fixed bars, the middle one being 

 connected to each of the others by five small bars (ten 

 small bars in all). The terminals of the battery are in 

 both cases connected with the two outside bars, and the 

 current divides itself between the five small bars as it 

 passes from each large bar to the next. An ordinary 



SCENE DE LOiIeIRA 



SALLE DES TELEPHONES 



Fig. 2. — Connections- between Opera and hearing-room. 



five-barred gate, without the sloping tie, gives a good 

 idea of the general form. It is one of the many forms 

 which have been given to Cro5sley's microphonic trans- 

 mitter, and is believed to be about on a par with many 

 other forms.] 



On account of the multiplicity and variety of sounds 

 which it is capable of transmitting, it has been fixed on 

 a leaden socl;et standing on four india-rubber feet, to 

 deaden the effect of the vibrations of the floor of the 

 stage. The necessity for such an arrangement is obvious 

 in a theatre where the floor is continually being shaken 

 by dancing. 



At the Opera House there are ten transmitters of this 

 kind disposed on both sides of the prompter's box along 

 the edge of the stage. The arrangements suitable for 

 any theatre vary according to the position and magnitude 

 of its stage ; and M. Ader informs us that he intends to 

 double the number of transmitters at the Opera House, 

 so as to render the sounds still more intense. 



The receivers in the telephonic rooms of the Exhibition 

 are the tclc'p/ionrs a siircxcitation of M. Ader, which we 

 have described more than once in this journal, and the 

 arrangement of the batteries which work these multiple 

 systems possesses no special feature. The batteries are 



