fluid conductors when transmitting the electric current. 1 8 1 
tion of sodium 1 : 1,200,000, there was still a considerable 
radiation from the positive pole, but not extending over the 
whole surface. On reducing the proportion of sodium by a 
third addition of an equal quantity of the pure metal to 
1 : 1,600,000, a feeble radiation was still sensible in the same 
direction. 
so. Ammonium. A considerable quantity of the amalgam of 
this singular substance introduced into mercury under a solu- 
tion of soda did not communicate to it any power of rotation. 
This remarkable result, which goes to separate ammonium 
by a definite character from the other metallic bases of the 
alkalies, was again obtained on repeating the experiment. It 
is possible, indeed, that a complete insolubility of the amalgam 
in pure mercury may be the cause of this want of action, 
but the supposition must be allowed to be a very forced one. 
Si. Barium. This metallic body amalgamates with the 
utmost readiness with a power of eight pairs of plates when 
the muriate is acted on ; a small globule of mercury at the 
negative wire throwing out beautiful arborescences, and fixing 
into a highly crystalline, pretty permanent, solid amalgam. 
A very minute quantity of this introduced into mercury un- 
der solution of soda, gives it the positive property. Its efficacy, 
in reversing the direction of the currents, is strikingly sensi- 
ble when introduced into a quantity of mercury kept in a 
state of negative rotation under oxalic acid. The amalgam 
of mercury and barium added in small quantities to pure 
mercury, imparts to it the same property as we noticed in 
the case of sodium, of forming a Voltaic combination with a 
wire brought in contact with it under a saline solution, and 
the action so produced is much more lasting. 
