On a Simple Resonamce Experiment. 623 



Conclusion. 



The investigation in this paper has been largely restricted 

 to a consideration of the various modes in which compound 

 molecules o£ the two elements hydrogen and carbon may be 

 formed. It will be evident to those who have followed the 

 processes that, when some of the other kinds of atoms are 

 introduced, the line of investigation will be greatly extended, 

 and seems likely to have important practical consequences. 

 Some of these questions have already been considered, but it 

 must be borne in mind that before exact results can be 

 obtained by this method the charts for the fields of force for 

 each pair of atoms entering the compound molecule must be 

 worked out. To add the single element oxygen, for example, 

 requires three more charts, one for oxygen on oxygen, a 

 second for oxygen on hydrogen, and a third for oxygen on 

 carbon, and these charts are not yet available. 



LXII. A Simple Resonance Experiment. By 0. Steels, 

 Professor of Applied Electricity in the University of Ghent 

 (Belgium), Chief- Engineer and Director in the Belgian 

 Telegraphic Department *. 



1. CQNCE resonance phenomena play an important part 

 O in several physical questions, it is of some interest, 

 especially for lecture purposes, to devise a simple experiment 

 to illustrate this phenomenon, and to bring it within the grasp 

 of common knowledge and observation. 



Text-books have described devices making use of pendulums. 

 In the Jahrbuch der drahtlose Telegraphie, 1912, we find the 

 theory of a mechanical arrangement, the equations for which 

 are similar to those arising in the case of the electrical 

 resonance of two coupled electrical circuits excited by a 

 third one. 



In the simple case of two electrical circuits loosely coupled, 

 we know that it is easy to plot a resonance curve makino- 

 use, for instance, of some wavemeter; but the experiment, 

 though not difficult, is not very striking. 



For this reason it is advisable to arrange an electro- 

 mechanical combination, making use of apparatus to be 

 found in any laboratory, and which is consequently easy to 

 put together. 



2. Let us take a little magnet N — for instance, one of 

 those little models which are used for tracing the force-lines 



* Communicated by Prof. A. W. Porter, F.R.S. 



