166 Foreign and Miscellaneous Intelligence. 



II. CHEMICAL SCIENCE. 



1. GALVANIC CURRENTS DURING THE DECOMPOSITION OF 

 WATER. 



The following description is from the personal observation of Pro- 

 fessor Silliman. * In the decomposition of water by the galvanic 

 power, two tubes being filled with water, and inverted in a vessel 

 filled with that fluid, their orifices being about one inch apart and 

 the connexion established through the fluid by slips of platina, I 

 had recently the satisfaction of observing distinctly the currents of 

 gas as they took their departure to their respective poles. It has 

 been a problem, whether the water is decomposed under one tube, 

 or the other tube, or at some intermediate point; but, in the expe- 

 riment referred to, ocular demonstration was exhibited, that the 

 decomposition took place simultaneously, under both tubes, and not 

 at any intermediate point. This appeared from the fact, that under 

 each tube a current of gas rose vertically from the platina slip, and 

 collected in the top of the tube, while another current shot off 

 laterally and took up its march towards the opposite pole beneath 

 the contiguous tube : as this process was going on at the same 

 time under both tubes, it follows that there were opposite currents 

 of gas, but they occasioned less mutual disturbance than might 

 have been supposed ; because the levity of the hydrogen and the 

 gravity of the oxygen determined them to pass each other at dif- 

 ferent levels, and although many bubbles were buoyed up in the 

 passage, and made their escape, and were lost by passing through 

 the water intermediate between the two tubes, a large part of the 

 gases was collected in the respective tubes. The process was con- 

 tinued for several hours with a large battery, and the currents were 

 palpable to all the bystanders. With a magriifying-glass the ap- 

 pearance was beautiful, and nothing can exhibit more decisively the 

 all-dominant power of the galvanic influence in causing even gaseous 

 elements to separate at different points, and to pass horizontally, 

 in opposition, through at least two inches of water, until they 

 arrived at the poles by which they were respectively attracted : but, 

 on examining the gases in the two tubes, so far from finding the 

 oxygen gas in the one and the hydrogen in the other, there was 

 found in both a highly explosive mixture, which gave a very sharp 

 report when a flame was applied ; and in fact the result was pre- 

 cisely the same as when the two tubes, standing in different vessels 

 and furnished with metallic caps and depending platina wires, to 

 connect them with the slips of the same metal below, are joined by 

 a good conductor touching the caps. 



Did the strong mechanical conflict of the two opposite currents 

 cause the gases to be intermingled and thus to be in part carried 

 into the stream? or did a portion of each gas fail to be expelled from 

 the tube by the attractions and repulsions, and thus rise by mere 



