374 Hydrogen Gas. 
6. Leyden Jar. When water has been spate frozen 
in a Leyden bottle, the outside coating of which is not 
insulated, the bottle receives a weak electric charge ; the 
outside becomes negative and the inside positive. If the 
water be quickly thawed, the electric action is reversed, 
the inside becomes negative and the outside positive. 
Grothus. 
7. Chemical effects of Magnetism. According to profes- 
sors Hanstein and Maselsmann this effect may be shewn 
as follows. Bend a glass tube into a syphon, and place in 
the angle a portion of pea not sufficient to close the 
connection between the two legs ; then introduce a soiu- 
tion of nitrate of silver until it rises in both branches. 
Then place the branches of the syphon in the magnetic 
meridian and the Arbor Diane will form much more ra- 
pidly and in more eres crystals, than if the branches be 
placed in the di of east and west. e crystalliza- 
in the sianiniose perfect in the northern branch. 
If we the iyptoe is in a plane perpendicular to “the 
meridian, an artificial magnet be Winighe near it, the silver 
will be deposited more abundantly, and in this case the 
south branch is more active than the north. © 
Marray has made an experiment analogous to this by 
putting an iron rod into very dilute nitrate of silver. If 
the rod be not magnetized the silver is not reduced, but as 
soon as a magnet is brought to touch it, the reduction takes 
place. A magnet covered with varnish will equally effect 
the reduction, but in this case he finds, in opposition to 
Hoes and Masselsmann that the strongest action is at 
rth pole. Ludecke has observed that when a cles 
ven filled with a concentrated saline ree (e- 8 
aes 
er 
sot, which, by the more che diies c ye in that 
San _ When nice gas, “‘Tébine 
ute sulphuric acid,) is passed meats pure plcoboht 
m iron filings and Bi 
