76 Intelligence and Miscellaneous Articles. 



discharge iteelf into a vessel containing water, the orifice being 

 caused to dip beneath the surface of the latter. In this case the 

 mass of liquid was continuous, but the notes were nevertheless pro- 

 duced ; thus showing that the vibrations which produce them must 

 take place in the glass cylinder itself; — and corroborating the con- 

 clusions arrived at by Savart from his earliest experiments on this 

 subject. The pitch of the note depends upon the height of the 

 liquid column which produces it ; and by attaching a tube of an 

 inch in diameter, furnished with a perforated bottom, to a cylindrical 

 vessel about IS inches wide, and filling the whole with water, a note 

 of long duration and of sensibly constant pitch was obtained. 



The lecturer concluded with an experimental illustration of the 

 total reflexion of light at the common surface of two media of dif- 

 ferent refractive indices. The tube communicating with the 

 reservoir before referred to was fitted into the top of a small box, into 

 one of the sides of which was fitted a glass tube ^ of an inch wide 

 and 5 inches long. The side of the box opposite to that through 

 which the glass tube was introduced was of glass. Behind the box 

 was placed a camera, by means of which the electric light could be 

 condensed and caused to pass, first through the glass back of the 

 box, and then through the tube in front, so as to form a white disc 

 upon a screen held in the direct path of the light. When, however, 

 the cock was turned so as to permit water to spout from the tube, 

 the light on reaching the limiting surface of air and water was 

 totally reflected, and seemed to be washed downward by the de- 

 scending liquid, the latter being thereby caused to present a beautiful 

 illuminated appearance. 



X. Intelligence and Miscellaneous Articles. 



ON THE PRINCIPLES WHICH GOVERN THE DISENGAGEMENT OF 

 ELECTRICITY IN CHEMICAL ACTIONS. BY M. BECQUEREL, 



ALL the questions relating to the evolution of electricity are ex- 

 ceedingly interesting in the physico-chemical sciences and their 

 application to the arts and manufactures, seeing that they are of the 

 same order as those which aflfect the production of heat during 

 combustion . 



The amount of electricity associated with the molecules of bodies 

 is so great as to startle the imagination, as I showed in 1846. Un- 

 fortunately only an excessively small portion of this electricity can 

 be collected, in consequence of the recomposition which takes place 

 on the contact of tlie bodies. The eff^orts of physicists must be 

 directed to the discovery of the means of preventing this recomposi- 

 tion, if they wish to furnish society with a motive power which may 

 contend successfully with steam, producing much more varied eflfects, 

 as it acts not only as a mechanical force, but also physically in the 

 production of heat and light, and chemically in the. decomposition 

 of bodies and in efi^ecting the combination of their elements. 



Such was the end which I proposed to myself in 1823, when I pro- 

 duced my researches on the disengagement of electricity in chemical 

 reactiooB, researches which enabled me to establish the principles 



