Effluvia from Chemical or from Voltaic Reactions. 27 



to be attracted to the jets by the positively electrified efflu- 

 vium *. 



14. Various other forms of experiment all indicated that the 

 effluvium was highly electrified but did not readily part with 

 its charge to bodies immersed in it. Of these the following is 

 typical. A large beaker was suspended by silk threads mouth 

 downwards, so that it could be filled by gaseous displacement 

 with the effluvium from zinc dissolving in a beaker of hydro- 

 chloric acid. An insulating stand, on Mascart's principle, 

 was made by cementing with paraffin a glass rod upright on 

 a flat-bottomed flask and drying the glass surfaces by strong 

 sulphuric acid placed on the paraffin. On the top of the rod 

 could be placed either a brass ball 4 centim. in diameter, 

 an inverted glass flask about 6 centim. in diameter with 

 moistened surface, or a smooth-skinned apple a little smaller 

 than the flask. Each of these could be immersed in the freshly 

 generated gas for a given time in order to receive any charge 

 communicated by contact with the electrified matter, or else 

 caused to take a charge inductively by a momentary earth 

 connexion while so immersed. They were each then carried 

 to the electrometer, and when put in contact with it gave the 

 following deflexions : — 



Apple immersed in the effluvium for 2 minutes. + 230. 



H „ +180. 



,, and momentarily put to earth. About— 550. 



Wet flask immersed for 1^ minutes. + off scale. 



Brass ball „ 1± „ + 160. 



Brass ball immersed and momentarily put to earth. — 400. 



— 45 



In the last experiment five minutes were allowed to elapse 

 after filling the large beaker, when the greater part of the 

 fog had disappeared. In the others the amount of charge 

 was doubtless influenced by the greater or less volume of 

 electrified matter that happened to be present. 



15. In order to test the electrification of the hydrogen itself 

 immediately after its generation and with the fog removed, 

 drying by calcium chloride or other substances was suggested. 



A small flask was fitted with a chloride-of-calcium tube 1*3 

 centim. wude by about 10 centim. long, filled with the chloride 

 in the usual granulated form and kept in place by a cotton- 

 wool plug at each end. Zinc and hydrochloric acid were 

 placed in the flask, and a water-dropping funnel connected 



* The electrification of the proof-plane used by Mr. Enright, as 

 described on p. 65 of his paper, was perhaps due to the same cause — 

 imperfect insulation allowing leakage. 



