SCIENTIFIC CONGRESS OF CARLSRUHE. 367 



upon the circumstance here, it is because we find in it an answer to 

 one of the many prejudices which the German savant entertains in 

 regard to the French. The latter is currently reproached with pub- 

 lishing in his own name facts discovered and described beyond the 

 Ehine, when the truth is, that the French savant is scarcely ever able 

 to read German, and, if he could, would be quite incapable of keeping 

 pace with the thousand assertions, more or less substantiated, which 

 swarm in Teutonic journals, besides the danger of encountering some 

 other savant better informed with regard to a priority of title. What 

 makes the instance on which we are remarking more singular is, that 

 the experiment of the jet d'eau was consigned to the press, not fifty 

 years ago and in some forgotten compilatiou, but last year, and in the 

 Annalen der Physik of M. Poggendorff. It was there that, in seeking 

 for something else, we found it, the morning referred to, but described 

 in still greater detail by M. A. Fuchs, professor in the Lyceum of 

 Presbourg. 



The priority of M. Fuchs is doubtless not yet known to our neigh- 

 bors beyond the Rhine; but when they have learned it, this will not 

 remove the prejudice we have adverted to, nor any other, any more than 

 the French will abandon their opposite propensity to admire all which 

 comes from Germany, and to concede a vast erudition and profound 

 knowledge to every one who calls himself a German professor. 



Before leaving the subject of this interesting experiment, we must 

 add that, according to M. Fuchs, the sensibility of the thread of water 

 is such, that when the head of the observer is brought very close to the 

 jet, the latter is deflected if the operator does no more than pass a hand 

 through his hair. 



We return to our session, having still to listen to lectures of "a 

 high order. Among them, M. Plucker, the eminent professor of the 

 University of Bonn, set forth with great distinctness his remarkable 

 researches respecting the electric spectrum produced by currents of 

 induction, whether in a vacuum or in different mediums, embracing — 



First. A simple gaseous body. 

 Second. A mixture of several gases. 

 Third. A compound gas. 



&■ 



M. Plucker is convinced that a perfect vacuum is incapable of con- 

 ducting electricity. 



The simple gases which he examined were hydrogen and azote ; in 

 exposing a mixture of these two gases to the current generated by an 

 apparatus of Ruhmkorff, a peculiar spectrum is obtained which may 

 be also realized by superposing purely and simply a spectrum produced 

 by hydrogen on another spectrum produced by azote. In effect, the 

 same spectrum results, when a current of induction is made to pass 

 into an atmosphere of ammoniacal gas. Thence we may infer that 

 the ammonia,cal gas is decomposed by the current of induction. M. 

 Plucker arrives at analogous conclusions on the subject of carbonic 

 acid, of which the spectrum is identical with that produced by a mix- 

 ture of oxygen and of the oxyd of carbon, as well as with the image 

 obtained by superposing the spectrums of these two gases. 



In addition, the same savant gave an account of the remarkable 



