352 EECENT PROGRESS IN PHYSICS. 



Solution of the problems recently proposed on branclied galvaniiL 

 currents, for the discharge current of the electrical battery, — (Poo- 

 Ann., LXVIII, 136.) 



On the ratio of tension in the discharge current of the electrica 

 battery.— (Pog. Ann., LXIX, 11.) 



On the comparison of the electrical formula with the galvanic— 

 (Pog. Ann., LXIX, 421.) 



The experiments mentioned in these memoirs are very badly del 

 scribed ; the discussions inflated, confused, and full of difficult formulas! 

 which do not lead to simple, clear, and well founded results. 



Since the design of this report is to present to the reader the prO' 

 gress of physics, and not to weary him with criticisms on fruitlesr 

 labors, I need say no more of Knochenhauer's memoir on the latera; 

 current and kindred subjects. The criticism on the abovementioned 

 paper suffices to justify me in this respect. 



§ 69. Charging current of the electrical battery. — In Fig. 68 let o 

 and b denote two electrical batteries, both of which are insulated ( 

 The exterior coatings of both batteries being in metallic connexion,] 

 suppose a to be charged and b to remain uncharged. 



Fig. 68. Now, if any suitable discharger, 



^____^„«-^ fitted to the knob of the jar b, ap-i 



^feo^— — f% preaches the knob of the charged 



^' Y jar, a spark passes, the jar a be- 



^^p '^^ comes partially discharged, a part 



!« I ill °^ *^® ^®' ^'^ positive electricity; 



fr^|S^ |_^ ^ which was accumulated on the in- 



I ;:^ |: ; J ner coating of a, passes with a 



<^„M.,. i..,EJfS! j^,„i ^.„„lt::S Tr;ai> spark to the inner coating of b, 



j II while a corresponding quantity of 



' negative electricity passes without 



a s[)ark, by the cunducting connexion of the outer coatings, from a 

 tob. 



In this manner a is partly discharged and b charged ; the charge 

 of b is not gradual, as in ordinary charging of jars, but very rapid. 

 Dove terms the current which, passing from the outer coating of a 

 to that of b, charges the latter battery, the charging current, (Ladungs-' 

 Strom,) and he has compared the action of this current with the action 

 of the discharge current already amply investigated. He found the^ 

 following results, (Pog. Ann,, LXIV, 81 :) 



1. Induction. In the outer connecting wire a cylindrical induction 

 spiral was introduced, surrounded by an exterior secondary spiral. 

 The effects were the same as in the discharge stroke. 



2. Sparks. The outer connecting wire having been interrupted, a 

 brilliant white spark, with a loud report, appeared at the place of 

 external interruption the instant tlie spark at the inner conducting 

 wire passed. A moist thread being introduced into the inner con- 

 ducting wire, the spark assumes a redish yellow color and has a feeble 

 report ; the same change is also indicated in the place of interruption 

 of the outer connecting wire, in which there is no moist thread. 



Dove found further that the "charging current" produced in the : 

 same manner as the discharge current. i'i 



