xliv GENERAL SUMMARY OF SCIENTIFIC AND 



Schrauf and Dana have investigated the curious electrical 

 properties exhibited by some crystallized minerals when they 

 are gently heated. Edlund's theory of the physical nature of 

 electricity is supported by Emsmann and others, according 

 to whom electricity, galvanism, and magnetism are but mani- 

 festations of the workings of that same aether that suffices to 

 explain the phenomena of light and heat. Mr. Thayer has 

 studied the action of condensers made with solid dielectrics. 

 The chemical influences of the galvanic current have been 

 studied by Brodie and the Messrs. Thenaud, who have ob- 

 served interesting cases of synthesis. Bolzmann, with refer- 

 ence to dielectric absorption, shows that the molecules of elec- 

 trized bodies are themselves polarized, thus confirming in a 

 striking manner the opinions of Faraday. Similarly, Streintz 

 shows that a current of electricity passing through a wire 

 expands it lengthwise more than is due to its heat, as though 

 the molecules were polarized ; and Gore adopts a similar 

 view with reference to magnetism, which is, he thinks, an at- 

 tribute of every substance whose molecules admit of a certain 

 special arrangement. On the other hand, Cazin has shown 

 that if opposing galvanic currents surround a bar so that an 

 attempt is made to give opposite magnetisms to the same 

 portion thereof, there is only an evolution of heat. The com- 

 mittee of the British Association recommend, on the score 

 of simplicity, the general adoption of the centimeter, the 

 gramme, and the second, as the three fundamental units in 

 electricity and magnetism. 



Of the applications of electricity, the most valuable in a 

 practical way is the perfection being attained in the Stearns 

 duplex system of telegraphy. A quadruple system has even 

 been shown to be possible. The remarkable performances 

 of Mr. Little's automatic system, which is now in daily 

 operation between New York and Washington and other 

 cities, gives us a glimpse of the wonderful future of electric 

 telegraphy. 



CHEMISTRY. 



The progress in General Chemistry has been very marked, 

 the opinion that inorganic molecules have a much more com- 

 plex constitution than organic having constantly gained 

 ground. Of course this greater complexity must be of the 



