xxiv President's Address 



If we glance back over the past year's history of scientific 

 research and progress, we find but little of more than ordi- 

 nary interest to arrest our attention. There are, however, 

 one or two instances which may worthily claim our atten- 

 tion for a few moments. 



In my last address I referred to that interesting little 

 instrument the Radiometer, and to Mr. Crooke's discoveries 

 of the action of Light and heat on bodies in vacuo ; and one 

 of the instruments was exhibited and described by Mr. 

 Foord, Avho also made some remarks on the experiments he 

 had made with it, and the principles involved in its peculiar 

 action. The behaviour of light bodies freely suspended in 

 vacao, under the influence of heat and light, seemed at first 

 inexplicable according to known laws, and the question 

 arose whether Mr. Crooke's experiments did not point to 

 the existence of a new force. Our best physicists, however, 

 suggested that the whole phenomena might be satisfactorily 

 explained as pertaining to the action of radiant heat in a 

 partial vacuum. Mr. Crooke has now, by the continuance 

 of his investigation, conclusively proved this to be the case, 

 and also finds that if instead of an ordinary vacuum the 

 most perfect one attainable is secured, the action of the 

 Radiometer is largely weakened, and indeed ceases alto^ 

 gether. 



Few sciences have made such strides in a utilitarian 

 direction as that of Electricity _, more especially in reference 

 to Telegraphy. We had scarcely been able to realise the 

 fact that two different messages could be sent simultaneously 

 on a single wire in opposite directions, as in the duplex 

 system of telegraphy, than we hear of a quadruplex and 

 multiple system being in actual operation, the latter em- 

 bracing the power of sending two or more messages each 

 way simultaneously on a single line, provided a synchronous 

 movement or identical revolution of similar portions of the 



