SCO Experiments made by the Galvanic Seciety of Paris 



Reference to the Engraving of Mr. Peter Herbert's 

 Book-case Bolt, Plate VII. Fig. 3, 4. 



KL, Fig. 3, represents the two stiles of the doors of a 

 folding book-case. 



M, the key-hole of a lock with two bolts, which are more 

 clearly shown .at Fig. 4, where the back of the lock N 

 shows the two bolts of the lock pressing back a sliding- 

 piece ; on the front part of this sliding-piece in Fig. 3, 

 two small friction rollers are placed at P, in the act of press- 

 ing against two levers, crossing on one common fulcrum 

 R, to each end of which, shorter levers SS above and below 

 are connected by joints. These short levers act upon two 

 long bolts, whose extremities are shown at TT, having each 

 a helical spring at V V. In the state as engraved, the doors 

 are locked and bolted. 



On drawing back the bolts of the lock by means of the 

 key, the helical springs, VV, press against the plates UU, 

 through which the long bolts pass,; they force back the long 

 bolts and sliding-piece O, and allow both the doors to open. 



XLI. Notices of Experiments made by the Galvanic Society 

 of' Paris. By M. Riffault, one of the Members % 



JVi. Marechaux of We'sel, correspondent of the Galvanic 

 society, announces that he has ascertained that water, 

 whether pure or mixed with an acid, or saturated with any 

 salt, is not a necessary ingredient in the production of the 

 effects of the Galvanic fluid. lie adds that for some time 

 past he has constructed columns of zinc and brass, with the 

 interposition of disks of pasteboard not moistened, which 

 were of great se/vice to him. The Galvanic society being in- 

 terested in a fact of this nature, they determined to repeat 

 the experiments of M. Marechaux, as described in his let- 

 ter : disks of zinc which had been employed before were 



* From the Anrtales de Chimie, tcm. Ivi. page Gl. 



completely 



