80 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



tatory power of the tartrates is threefold that of tartaric acid, 

 thus following the laws of simple relations. 1 E, VII., 97. 



INFLUENCE OF A DIAMAGNETIC BODY ON THE ELECTRIC 



CURRENT. 



Professor Stephan has been engaged in investigating the 

 phenomena exhibited when an electric current is opened or 

 closed in the presence of a diamagnetic body, and has arrived 

 at the following conclusions : First, the presence of a diamag- 

 netic body at the moment of closing the circuit accelerates 

 the ascending movement of the current, and the chemical ac- 

 tion developed simultaneously within the pile is less than 

 when the closing takes place in the absence of a diamagnetic 

 body. Second, the heat developed at the moment of opening 

 the current by the secondary current is less when the inter- 

 ruption takes place in the presence of a diamagnetic body. 

 Third, when the current sets in motion a diamagnetic body, 

 the action simultaneously supplied by the chemical force in- 

 side of the pile will be to the live force furnished by this body 

 as two to one. This surplus of chemical action is manifested 

 as soon as we open the current in the secondary circuit, rein- 

 forced by the absence of a diamagnetic body. The contrary 

 takes place every time that a body of this nature is moved 

 in a direction opposite to that of the electro-dynamic forces. 

 Fourth, the energy of the needle increases or diminishes ac- 

 cording as it is removed or approximated to a diamagnetic 

 body. If this body is set in motion by a needle it furnishes 

 a sum of live force equivalent to the action of the live forces 

 acting in the needle. 3 B,Jidy 18, 1872, 482. 



TRANSMISSION OF SOUND IN WATER. 



During the siege of Paris a series of experiments was made 

 within the city with a view to determine the possibility of 

 establishing a system of telegraphic communication, through 

 the waters of the Seine, between the city and the country in 

 the rear of the besieging lines. The result, however, was not 

 at all satisfactory, although some interesting conclusions were 

 placed on record. Among them were the following: 1. The 

 range of sound in running water, even in the direction of the 

 stream, is much less than in still water, as in a lake. 2. When 

 the volume and depth of sound are greatly augmented, there 



