482 Scientific Industries. 



the firm. Ebonite is hardened rubber, and " the method of its 

 manufacture was discovered," says Colonel Silver, " in a curious 

 manner. Hollow indiarubber balls are made out of sheet rubber, 

 cut in two sections, and inflated by oxalic acid in a bath of melted 

 sulphur. During the process one of the balls fell unnoticed to 

 the bottom of the bath. When found at the end of the week it 

 had hardened into ebonite." Ebonite is invaluable in the manu- 

 facture of electrical instruments, because of its electrical non- 

 conductivity, and it is much used also because of its resistance to 

 chemical action. Its accidental discovery therefore was of great 

 value to the firm commercially. 



In 1864 the business was converted into a limited liability com- 

 pany, Silver's Indiarubber Works and Telegraph Company, Ltd. 



The manufacture of submarine cables was commenced by the 

 firm, and in 1868-9 a cable was laid between Havana and Key 

 West, U.S.A., under the direction of Sir Charles Bright, who had 

 been associated with the laying of the first unsuccessful Atlantic 

 cable in 1858. The ss. " Dacia " was acquired at this time, and 

 converted into a cable ship. Since this cable was laid, over 40,000 

 miles of submarine cable have been laid by the company, and other 

 cable ships have been acquired. 



The works now occupy over seventeen acres, and some 3,000 

 employees are engaged by the firm in their various departmeuts. 

 To cope with an extensive continental business, works have been 

 constructed at Persan, Seine-et-Oise, France. 



The weekly consumption of coal at the Silvertown factories 

 exceeds 1,000 tons a week, which shows the importance of an 

 ample supply of cheap coal. In addition to all kinds of rubber and 

 gutta-percha goods, whose name is legion, and the use of 

 which is rapidly extending, the firm manufacture everything 

 connected with electricity. 



HENLEY & Co., NORTH WOOLWICH. 



The growth of North Woolwich is identified with these electrical 

 works. Mr. W. T. Henley, the founder of the firm, worked in the 

 docks for five years learning the use of tools in the making of elec- 

 trical instruments, then, about 1833, he came under the notice of 

 Wheatstone, of telegraph instrument fame, who forthwith engaged 

 him. Mr. Henley must have been a shrewd business man as well 

 as an inventor, two qualities which do not always go together, and 

 while with Wheatstone he invented a magnetic telegraph and 

 promoted a company to purchase the patent. 



