Now Ready, 1 Volume 12mo, 250 pages, price 2s. cloth lettered, 



THE ELECTEIC TELEGRAPH 



POPULARISED. 



Yj^TH ONE HUNDRED ILLUSTRATIONS. 

 By DIONYSIUS LAEDNEE, D.C.L., 



From the " Museum of Science and Art." 



"The reader will find the most complete and intelligible description of Telegraphic 

 Apparatus in Dr. Lardner's admirable chapters on the subject." North British Review. 



PEEFACE. 



IN the composition of this volume my purpose has been to render intelligible to 

 all who can read, irrespective of any previous scientific acquirements, the various 

 forms of telegraph in actual operation in different parts of the world, and the manner 

 in which their marvellous effects are produced. Since the instrument in one form or 

 another involves all the great laws governing electrical and magnetical phenomena, 

 the discovery of which will render for ever memorable the researches of the eminent 

 scientific men of the last half century, it was necessary to include in the exposition 

 of each piece of apparatus such an account of the physical principle upon which its 

 use depends, as should render its application and effects understood. Descriptions 

 of such apparatus, however clearly expressed, would have been obscure without 

 graphic illustrations to correspond with them. These have accordingly been supplied, 

 as will be seen, with no sparing hand. 



No two countries agree in adopting the same form of telegraphic instrument, and 

 even in the same country different forms of telegraph are vised by different companies 

 and for different purposes. Since these various instruments are always different in 

 the details of their construction and often totally distinct in their principle and mode 

 of o})eration, it was necessary to explain each in succession, and to do so correctly 

 it was necessary to seek and obtain authentic documents, descriptions, and drawings 

 from those who were placed in the direction and superintendence of the telegraphs 

 in various parts of the continent of Europe and in the United States. 



The reader of this little volume will find in its pages abundant evidence that no 

 pains or cost have been spared in these researches. 



The history of the invention of the Electric Telegraph is a subject upon which 

 I have not judged it expedient to enter. The details of such a narrative, necessarily 

 numerous and complicated, involving several questions of disputed priority and con- 

 tested claims, besides filling a much larger volume than the present, would present 

 few attractions for the large masses to whom our work is addressed. 



The Electric Telegraph is not the invention of an individual. As it now exists, 

 it is the joint production of many eminent scientific men and distinguished artists of 

 various countries, whose labours and experimental researches on the subject have 

 been spread over the last twenty years. Not being prepared to engage in a complete 

 account of the progressive results of these labours, I have in the following work 

 generally abstained from the mention of inventors, from a desire to avoid the risk of 

 appearing to put forward some in undue preference to others who might be supposed 

 to have better claims to notice. There can, however, be no risk of committing an 

 injustice by stating that in England Professor Wheatstone, iu the United States 

 Professor Morse, in Bavaria M. Steinheil, in Prussia Dr. Siemens, and in France 

 MM. Breguet and Froment, have severally stood in the leading ranks of invention. 

 Besides these eminent persons may be mentioned, Mr. Bain, the inventor of the 

 electro-chemical telegraph ; Mr. Henley and the Messrs. Bright, who have improved 

 the magnetic telegraph ; Messrs. Brett, to whose genius and enterprise the world is 

 indebted for submarine telegraphs; Messrs. Newall and Co., who have been signalised 

 by the construction of submarine cables ; Mr. Walker, of the South Eastern Telegraph 

 Company ; and Mr. House, of the United States, the inventor of a printing telegraph 

 in extensive operation. 



LONDON : WALTON & MABEELY, 

 UPPER GOWER STREET, AND IVY LANE, PATERNOSTER ROW. 



