756 ANNUAL SEPORT SMITHSONIAN INSTITUTION, 1908. 



predicted that there would be retardation of signals in cables owing 

 to the coating of gutta-percha acting like the glass of a Leyden jar. 

 Forming the required differential equation and applying Fourier's 

 integi'ation of it, Thomson drew the conclusion that the time required 

 for the current at the distant end to reach a stated fraction of its 

 steady value would be proportional both to the resistance and to the 

 capacity; and as both of these are proportional to the length of the 

 cable, the retardation would be proportional to the square of the 

 length. This is the famous law of squares about which so much 

 dispute arose. This was followed by a further research " On peri- 

 staltic induction of electric currents," communicated to the British 

 Association in 1855, and afterwards in more complete mathematical 

 form to the Royal Society. 



Submarine telegraphy w^as " in the air." John and Jacob Brett 

 had pioneered the project for a Dover-Calais cable, and in 1851 

 Crampton successfully united England and France. In 1853 Holy- 

 head and Howth were connected by Mr. (later Sir) Charles Bright. 

 And these were follow^ed by the Dover-Ostend and longer cables. 

 Atlantic telegraphy became the dream of the telegraph engineer. 

 Cyrus W. Field, in 1856, negotiated a cable across the Gulf of St. 

 Lawrence, thus connecting Newfoundland to the American continent. 

 The Atlantic Telegraph Company was formed, with capital mostly 

 subscribed in England, to promote the great enterprise to join Ire- 

 land to Newfoundland. Field, Brett, Bright, Statham, and Wild- 

 man Whitehouse were the chief promoters. Bright was engineer, 

 Whitehouse (a retired medical man) electrician. In a pamphlet 

 issued by the company, in July, 1857, narrating the preliminary pro- 

 ceedings, the names of John Pender, of Manchester, and Professor 

 Thomson, of " 2, The College, Glasgow," are included in the list of 

 directors; and the statement is made that "the scientific world is 

 particularly indebted to Prof. W. Thomson, of Glasgow, for the 

 attention he had given to the theoretical investigation of the condi- 

 tions under which electrical currents move in long insulated wires, 

 and Mr. ^Vhitehouse has had the advantage of this gentleman's 

 presence at his experiments, and counsel, upon several occasions, as 

 well as the gratification resulting from his countenance and coopera- 

 tion as one of the directors of the company." This is one side of the 

 matter. The other side is that Mr. Whitehouse had, at the British 

 Association meeting in 1856, read a paper challenging the law of 

 squares, and declaring that if it was true Atlantic telegraphy was 

 hopeless. He professed to refute it by experiments, the true sig- 

 nificance of which was disposed of by Thomson in two letters in The 

 Athenaeum. He pointed out that success la}^ primarily in adequate 

 section of conductor, and hinted at a remedy (deduced from 



