The Explosion of Hydrogen and Chlorine. 5 



other to a tower filled with lime and charcoal. The whole 

 apparatus was mounted on a stand, and the glass tubes 

 were fused together after filling. The current used was 

 supplied from seven large secondary cells, giving a voltage 

 of about 15. It passed through two adjustable resistances ; 

 one, iron wire; the other, carbon; then through a small low- 

 resistance Kohlrausch ammeter ; then to the electrolyser. 

 About 4 amperes was the greatest current we could use 

 without heating the liquid too much. 



We first experimented with a view to discover a 

 material suitable for the explosion tube. Pieces of pure 

 lead sealed up in dry chlorine are not much acted on, the 

 colour of the gas being visible after some weeks. We, 

 therefore, thought that a lead tube, after a certain time 

 would become coated internally with chloride and so be 

 available at least for the experiments with dry gases. After 

 many hours of saturation with dry chlorine, we found that 

 the gas continued to be absorbed with formation of a white 

 volatile solid decomposed by water, which analysis shewed 

 to be chloride of tin. This issued as a white cloud from the 

 end of the explosion tube. The best electrolytic mixture 

 we could obtain from the end of the explosion tube con- 

 tained not more than 80 % combustible gas (H2 + CI2). 



We, therefore, proceeded to have drawn some strong 

 glass tubing in long lengths. We succeeded in getting two 

 lengths of 30 and 34 feet respectively. These were slung 

 from a long ladder fixed against the wall of a dark corridor. 

 One end of each tube was then bent and fastened to the 

 other, so that the whole tube was about 21 yards long. 

 Various joints were used, plaster of Paris, certain cements, 

 and also fused chloride of silver, but none of these held so 

 well as a piece of strong rubber, slipped over the ends which 

 were previously ground smooth and pressed close together. 

 The rubber, being coated on the inside with paraffin, 

 was acted on very slowly by the chlorine. Fastened 



