PREFACE. 



THIS book was commenced with the intention of making it 

 a purely Elementary Treatise. As he proceeded with his 

 work, however, the Author became convinced that, in our 

 language, the want is much more felt of such books as 

 Schellen's, Dub's, Moigno's, Blavier's, and others, than of such 

 as he had proposed to make his. He has therefore endea- 

 voured to make it sufficiently elementary to come within 

 the comprehension of every educated man, and, at the same 

 time, sufficiently technical to be useful to electricians. The 

 work is divided into Two Parts : the First being confined to a 

 short history of the Electric Telegraph, and descriptions of 

 many of the past and existing methods and apparatus ; the 

 Second Part being confined exclusively to the more scientific 

 matter relating especially to Cable "Work. JSTo new theories 

 are started, nor has anything been introduced which expe- 

 rience has not confirmed as having merits to recommend it. 



In conclusion, the Author begs to tender his most hearty 

 thanks to Mr. Yarley, Professor Hughes, Mr. De Sauty, and 

 others, for advice or information they have given him on 



