PRESIDENTIAL ADDRESS, S.T.E. 1874. 229 



is Professor Piazzi Smyth's observations on the 

 Peak of Teneriffe. There, during several months 

 of perfectly fair weather, the surface of the 

 mountain was, if the electric test applied was 

 correct, positively electrified ; but Professor Piazzi 

 Smyth has, I believe, pointed out that the observ- 

 ations must not be relied upon. The instrument, 

 as he himself found, was not satisfactory. The 

 science of observing the atmospheric electricity 

 was then so much in its infancy that, though he 

 went prepared with the best instrument, and the 

 only existing rules for using it, there was a fatal 

 doubt as to whether the electricity was positive 

 or negative after all. But the fact that there has 

 been such a doubt is important. 



Now I suppose there will be a telegraph to 

 Teneriffe before long, and then I hope and trust 

 some of the operators will find time to climb the 

 Peak. I am sure that, even without an electric 

 object, they will go up the Peak. Now they must 

 go up the Peak with an electrometer in fine 

 weather, and ascertain whether the surface of the 

 earth is there positively or negatively electrified. 



