222 Dr. J. Monckman. Occluded Gases and [May 31, 



Fig. 2. 



up to about the middle, iu acidulated water, and made the negative 

 pole of a battery, and hydrogen liberated upon it for a few minutes. 

 After being dried it was tested with a small flame at distances of 

 1 cm. along its whole length. The result was a current from the 

 free wire towards that part on which hydrogen had been produced, 

 greatest at the junction of the free wire and the saturated 

 wire. 



H. Free "wire. 



The deflections were 0. 0. 0. 7. 10. ia~7. 4. 1. 0. 



Another experiment gave. . 0. 0. 5. 5. 5. 8. 8. 5. 5. 0. 0. 0. 



When wires of palladium were used more powerful effects of the 

 same kind were produced. Thus when two wires were used as the 

 electrodes in decomposing acidulated water, dried and gently heated 

 in contact, a current towards the hydrogen was observed. If heated 

 by a Bunsen flame complications arose from the hydrogen in the wire 

 taking fire. The flame produced could easily be seen 4 or 5 mm. away 

 from the Bunsen flame. 



Carbon rods were next tried. Gas-carbon was first tried, but I was 

 unable to get two rods sufficiently similar in composition to be of use, 

 their own thermo-electric currents being large enough to cover all 

 changes produced by gases. I had, however, no difficulty in getting 

 rods made for arc lamps to answer my purpose. They were heated to 

 a red heat to expel gases, and the ends were filed flat. 



It was found that when one of these rods was heated and placed 

 against the other (see fig. 3), the current was always from cold to hot 

 below 200° C. 



They were then used as the electrodes in decomposing dilute 

 sulphuric acid, dried carefully until no current was produced on placing 



