2 PHOTO-TELEGRAPHY 



proper order, while the dots and dashes forming a 

 letter, according to the Morse code, possess simi- 

 larly an intelligent meaning when grouped together 

 in correct order ; by building up a complete picture 

 with dots or small areas of varying depth, size, 

 or density we can produce a picture in a strictly 

 comparable manner. One ingenious attempt at the 

 solution of photo -telegraphy as ingenious as it is 

 impracticable has been to divide up a picture into 

 thousands of small parts, representing each by a 

 certain letter of the alphabet, according to its den- 

 sity ; thus a light part might be called C or D, a 

 dark part Y or Z, and so on. The letters are tele- 

 graphed to an operator, who forms a fresh picture 

 by building it up with small " parts/' whose 

 densities are in accordance with the respective 

 letters. Such a system is indeed possible, but would 

 require a very great amount of time. It is the 

 minutes and seconds which have to be saved in 

 telegraphing a picture especially in these days of 

 rapid railway transit, where photographic plates can 

 be sent to the newspaper office in a few hours, 

 so that only very late events are telegraphed. 



This book is not intended to be historical, and I 

 shall therefore refer only to such early processes as 

 have a direct bearing upon the work that is being 

 done to-day. Of early attempts at the transmission 

 of pictures, the Bakewell system deserves particular 

 notice, since upon it is based one of the three 



