296 



NATURE 



[May 6, 1920 



can be brought over to the right by means cf 

 the reading-handle H. It then returns to the left 

 with a slow, silent, and steady motion regulated 

 by the worm gearing W, which drives a small 

 paddle inserted in a viscous liquid. This paddle 

 can be inserted more or less deeply into the liquid 

 by the regulating nut R, and such is the range 



Fig. 2.— The optophone wiih book-rest removed. 



of adjustment possible that a line can be read in 

 anything from five seconds to five minutes, accord- 

 ing to the proficiency of the reader. When the 

 line is read, the next line is brought into focus by 

 the change-bar C, which works a friction grip 

 inside the bar on which the "tracer" is pivoted, 

 and can be adjusted for any desired line space 



Fig. 3. — The optophone complete with book-rest. 



by means of the screw attached to the change-bar. 

 A lever attached to the "tracer" enables the 

 operator to reverse this motion or to release the 

 whole " tracer " from the friction gear, so that it 

 may be quickly brought to the top of a page. 

 NO. 2636, VOL. 105] 



The festoon lamp is inserted at L, where it is 

 held by a spring clip, and whence it can easily be 

 removed for renewal even by a blind operator. 

 The balancer is inserted at B, and can be adjusted 

 for silence by means of the small handle shown. 



Pig"' 3 shows the apparatus from the top page 

 end and with telephone and flex connections 

 attached, as well as the book-rest R holding a 

 book. The adapters of these flex connections are 

 all of different sizes, and fit into different-sized 

 holes in such a manner that they cannot be 

 wrongly inserted — an important consideration with 

 blind operators. 



The various connections with their switches are 

 for the motor, the lamp, and the two selenium 

 circuits respectively. When the adapters are 

 removed, a cover can be placed over the whole 

 instrument, which clips on to the aluminium base, 

 and the optophone can thereupon be carried about 

 like a typewriter. 



Fig. 4 shows the manner in which the instru- 

 ment is manipulated by a blind person. 



Fig. 4. — Line-changing with the optophone. 



Special mention ought to be made of a con- 

 trivance for adjusting for various sizes of type. 

 The middle lens of the three shown in Fig. i is 

 mounted in a nut which can be screwed up and 

 down within the "tracer" by means of two gaps 

 cut in the upper cylindrical portion at T (Fig. 2). 

 The nut is provided with six nicks across the rim, 

 which enable a blind operator to count the number 

 of turns of the nut, and thus to adjust for any 

 definite size of type. This ingenious contrivance 

 is, I believe, due to Dr. Stroud. 



In practice it is found that, with the new 

 apparatus, the various adjustments for size of 

 type, length of line, and line interval are quite 

 easily made by blind persons, and that the instru- 

 ment, with all its delicate adjustments, can remain 

 in use for a long time without anything getting 

 out of order. It is therefore safe to say that the 

 problem of opening the world's literature to the 

 blind is now definitely solved. 



