76 Intelligence and Miscellaneous Articles. 



distillate, so that toward the end of the operation the retort con- 

 tained sulphide of carbon almost pure. 



To these facts, which tend to cast the greatest doubt on all the 

 results obtained by the laborious process of fractional distillation, I 

 now add the following. 



When a mixture containing the chlorides of ethylamine, diethyl- 

 amine, and triethylamine is distilled with caustic alkali, we should, 

 according to received ideas, expect to find the ethylamine, which is 

 a gas at ordinary temperatures, distil over first. Triethylamine, 

 which is at ordinary temperatures and pressures a liquid, separates 

 as such when a strong solution of its chloride is treated with caustic 

 alkali, and, floating on the surface, as I have before pointed out, we 

 would naturally expect to find it principally in the latter stages of 

 the distillation. The contrary is, however, the case when the less 

 substituted ammonias predominate in quantity. Almost the whole 

 of the triethylamine passes over in the first portions of the distillate, 

 and subsequent ones, though rich in ethylamine and diethylamine, 

 scarcely contain a trace of triethylamine. — Sillinian's American Jour- 

 nal, May 1864, 



NOTE ON THE RESIDUAL CHARGE OF ELECTRICAL CONDENSERS. 

 BY M. J. M. GAUGAIN. 



When after having discharged a Leyden jar it is left to itself 

 and after some time a new metallic connexion is established between 

 its armatures, we all know that a second spark is obtained, less 

 strong than the first. This fact, generally known as the secondary 

 discharge, has been designated by Mr. Faraday the residual charge. 

 I have adopted this latter name, slightly modifying the sense, to 

 designate, not the quantity of electricity which passes in a second 

 discharge, but all that remains after the original discharge, a quan- 

 tity which may give rise to a multitude of successive secondary 

 discharges. 



The existence of the residual charge is generally explained by 

 saying that part of the electricity of the armatures penetrates slowly 

 into the interior of the dielectric when the condenser is charged, 

 and that this portion, slowly absorbed, is restored with equal slow- 

 ness. But this explanation can certainly not apply to the experi- 

 ments of which I am about to speak ; for these experiments have 

 been made in such conditions that the electricity of the armatures 

 could not communicate itself to the dielectric, and yet the residual 

 charge formed in certain cases more than three-quarters of the total 

 charge. 



I worked, as in my former researches, on small fulminating 

 panes, with moveable armatures : in certain cases the armatures were 

 applied directly to the dielectric ; in other cases they were separated 

 by small layers of air of uniform thickness. The general results 

 were the same in either case. 



In a first series of researches I proposed to ascertain according to 

 what law the residual charge varies when the duration of the charge 



