ADDRESS. IxV 



To Mr. Hodgkinson we owe the determination of the true form of cast-iron 

 beams, or section of greatest strength ; the law of the elasticity of iron under 

 tensile and compressive forces; and the laws of resistance of columns to 

 compression. I look back to the days of our joint labour with unalloyed 

 pleasure and satisfaction. * 



I regret to say that another of our Vice-Presidents, my friend Mr. Joseph 

 Whitworth, is unable to be present with us through serious, but I hope not 

 dangerous, illness. To Mr. Whitworth mechanical science is indebted for 

 some of the most accurate and delicate pieces of mechanism ever executed ; 

 and the exactitude he has introduced into every mechanical operation will 

 long continue to be the admiration of posterity. His system of screw- 

 threads and gauges is now in general use throughout Europe. We owe to 

 him a machine for measuring with accuracy to the millionth of an inch, 

 employed in the production of standard gauges; and his laborious and 

 interesting experiments on rifled ordnance have resulted in the production 

 of a rifled small-arm and gun which have never been surpassed for range 

 and precision of fire. It is with pain that I have to refer to the cause which 

 deprives me of his presence and support at this meeting. 



A brief allusion must be made to that marvellous discovery which has 

 given to the present generation the power to turn the spark of heaven to the 

 uses of speech — to transmit along the slender wire for a thousand miles a 

 current of electricity that renders intelligible words and thoughts. This 

 wonderful discovery, so familiar to us, and so useful in our communications 

 to every part of the globe, we owe to Wheatstone, Thomson, De la Rive, 

 and others. In land-telegraphy the chief difficulties have been surmounted, 

 but in submarine telegraphy much remains to be accomplished. Failures 

 have been repeated so often as to call for a Commission on the part of the 

 Government to inquire into the causes, and the best means of overcom- 

 ing the difliculties which present themselves. I had the honour to serve on 

 that Commission, and I believe that from the report, and mass of evidence and 

 experimental research accumulated, the public will derive very important 

 information. It is well known that three conditions are essential to success 

 in the construction of ocean telegraphs — perfect insulation, external protec- 

 tion, and appropriate apparatus for laying the cable safely on its ocean bed. 

 That we are far from having succeeded in fulfilling these conditions is 

 evident from the fact that out of twelve thousand miles of submarine cable 

 which have been laid since 1851, only three thousand miles are actually in 

 working order ; so that three-fourths may be considered as a failure and loss 

 to the country. The insulators hitherto employed are subject to deteriora- 

 tion from mechanical violence, from chemical decomposition or decay, and 

 from the absorption of water ; but the last circumstance does not appear to 

 influence seriously the durability of cables. Electrically, india-rubber 

 possesses high advantages, and, next to it, Wray's compound and pure gutta- 

 percha far surpass the commercial gutta-percha hitherto employed ; but it 

 remains to be seen whether the mechanical and commercial ditticulties in 

 the employment of these new materials can be successfully overcome. The 

 external protecting covering is still a subject of anxious consideration. The 

 objections to iron wire are its weight and liability to corrosion. Hemp has 

 been substituted, but at present with no satisfactory result. All these diffi- 

 culties, together with those connected with the coiling and paying out of 

 the cable, will no doubt yield to careful experiment and the employment of 

 proper instruments in its construction and its final deposit on the bed of 

 the ocean. 



Irrespective of inland and international telegraphy, a new system of com- 

 munication has been introduced by Professor Wheatstone, whereby inter- 



1861. e 



