13G 



M. W. de Nicolaieve on a New Reaction 



the mica to take away the charges from the latter and to 

 facilitate the ionization of the air, but the illness of the author 

 has interrupted this experiment. He has made the following 

 experiment. A disk of mica K (fig. 6) is suspended excen- 

 trically to one side of the line of two-pointed terminals con- 

 nected to a Holtz machine. When the flame F is lighted the 

 disk K is displaced to the right by the current of hot air. 

 But when the electric machine is in action, the disk is 

 displaced at least twice as much. 



On the Electrostatic Field round an Electric Current. 



Apparatus. — In a large glass tube placed vertically are sus- 

 pended two loops, AEC and BFD (fig. 7), parallel to each 

 other, 4 to 5 mm. apart, and consisting of two strips of tinfoil, 



Fis\ 7. 



3 mm. wide, hanging down to a depth of 50 cm. The greater 

 this depth the more marked is the effect. The free ends, 

 A B C 1), are fixed in a card placed on the top of the tube. 



The points A and B of the loops are connected up to the 

 terminals of a battery of 100 volts. The points C and D are 

 either insulated or are connected through a rheostat of glow- 

 lamps. In the first case the loops are charged to the 

 potentials of the battery terminals ; in the second case a 

 constant current flows through the two loops in opposite 

 directions so that the electromagnetic forces tend to make 

 them repel each other. 



First Experiment. — The battery is unconnected, and the 

 loops are at rest. Then the battery is joined up and the 

 locps move toAvards each other. The attraction is produced 

 by the system of electrostatic tubes from the one loop to the 

 other. 



Second Experiment. — The battery circuit is completed by 



