RECENT PROGRESS IN PHYSICti. 411 



a'bout 3 ounces of water. A thermometer was immersed in the water 

 of each of the vessels, and the copper wires were so connected that they 

 formed part of the closing circuit of a constant zinc-platinum battery 

 of 8 cells, each of 8 square inches acting surface. 



When the battery was closed the wire in the oxygen became incan- 

 descent, while that in the hydrogen was not visibly ignited. The 

 temperature of the water, which was 60° F. in both vessels at the 

 beginning of the experiment, rose within 5 minutes to 70" in that 

 around the hydrogen tube, and to 81° in that around the one contain- 

 ing the oxygen. 



When both the tubes were filled with the same kind of gas the 

 temperature in both vessels rose to the same degree. 



This experiment decidedly proves that the appearance of less heat 

 in the wire immersed in hydrogen, with perfectly identical strength 

 of current, cannot be caused by a more rapid absorption of heat by 

 the hydrogen, because then, on the contrary, the water surrounding 

 the hydrogen tube ought to be heated sooner. All this indicates that, 

 in fact, a less production of heat takes place in the wire when sur- 

 rounded by hydrogen. 



G-rove has proved that this phenomenon is not caused by a small 

 amount of conduction of electricity by the hydrogen ; he has also de- 

 monstrated that it cannot be brought into any connexion with the 

 other physical properties of the gases, their density, specific heat, &c. 



As to the explanation of this peculiar fact, Grove endeavored in 

 vain to find a tolerable one, and in the course of his somewhat dilated 

 and obscure discussion arrives himself quite inconceivably at the con- 

 jecture that the diiference of the gases might have a similar effect to 

 a difference in the condition of the surfaces. This would essentially 

 coincide with Poggendorf's above mentioned opinion, which was pro- 

 pounded, however, before the experiment with the two glass tubes of 

 fig. 50, which in the most distinct manner refutes such a view, was 

 known to him. But Grove gives his consent to it immediately after 

 he has himself made and described the experiment, which proves that 

 this basis of explanation is inadmissible, and that the phenomenon 

 cannot be deduced from diff'erences in conduction and radiation of heat. 



In my opinion the phenomenon is still entirely isolated and unex- 

 plained. I do not think it profitable in such cases to cover up our 

 want of knowledge with dilated disquisition, in which the physical 

 scape-goat of our days, molecular action, has to play the principal part. 



§ 61. Effect of ignited platinum ivires on different gases. — It is a 

 known fact that some of the compound gases suff'er decomposition in 

 red hot tubes. Grove has produced similar effects upon these gases 

 by the action of ignited platinum wires. — (Phil. Trans., 1817, ]it. 1 ; 

 Pogg. Ann. LXXI, 194.) The following is the apparatus he used for 

 this purpose : 



Into the upper end of an eudiometer tube, fig. 51, a curved plati- 

 num wire was fused, from whose extremities copper wires conducted to 

 the two mercury cups which connected them with the poles of the 

 battery. The gas to be examined was confined over water, and, to 

 prevent the glass from becoming too much heated, the whole eudiome- 



