SIGNALLING THROUGH SPACE. 289 



elaborated cell-sap of their more industrious relations, they have 

 more energy to throw into the work of reproduction, more crops 

 of spores are found. They seem to have nothing parasitic on 

 them — no enemies, unless our old friends the Bacteria pay them 

 an occasional visit. Thos. S. Beardsmore. 



Signalling tbraugb Space witbout Miree. 



AT the Royal Institution on Friday, June 4th, Mr. Preece 

 delivered a lecture, of which the following is an abstract * : 

 " Mr. Preece, who is Chief Engineer of the Post Office 'I ele- 

 graph Department, has been an active investigator in this direction, 

 and the accounts of his own experiments, as well as those of 

 Marconi, proved full of interest. Science, he said, has given us 

 in telegraphy what may be called a new power and a new sense, 

 the discovery of which is among the greatest of the Victorian era. 

 He proceeded to give a summary of what is known respecting the 

 ether and the nature of wave-motion. The theory that light and 

 radiant electrical energy were identical in kind had been built up 

 by Clerk-Maxwell, and been confirmed by the test of experiment 

 by Hertz. Through the kindness of Professor Silvanus Thompson, 

 who had lent a model for the occasion, such as recently exhibited 

 at the Royal Society's conversazione, the lecturer was enabled to 

 graphically illustrate wave transmission, but the waves dealt with 

 in the new telegraphy, instead of vibrating with a frequency of 

 once or twice per second, were vibrating with a speed of millions or 

 hundreds of millions of oscillations per second. All radiations, it 

 was explained, are of one kind, and differ only in frequency, so 

 that, generally speaking, what can be done with light rays can also 

 be done with electrical rays, or radiant energy of any kind whatso- 

 ever. By means of diagrams the different directions assumed by 

 lines of force emanating from an electrically-charged body were 

 shown. From a charged brass sphere the lines radiate away straight 

 in all directions ; if, on the other hand, the section of a wire con- 



*From the Pharmaceutical Journal^ June 12th, 1897. 



