EXPERIMENTS GALVANIC 51 



tance, or any substance containing moisture, the cxperi- vessels connec- 

 ment will succeed. In my first attempt by this method, ^^^ ^Y animal 

 I separated the two portions of water by means of a bit of 

 very thin bladder, which was tied tight upon the end 

 of a glass tube, the tube M^as filled with pure water, which 

 the bladder did not suffer to escape. Another portion of - 

 water was put into a wine glass, tl\e tube was then im- 

 mersed into the water of the wineglass, with the bladder 

 downwards. The two portions being now separated by 

 the bladder, the positive wire was brought into the tube, 

 and the negative one into the wineglass. If with a mo- 

 derate sized apparatus the process be continued for even 

 half an hour, a pereeptabie quantity of muriatic acid will 

 be found in the water of the tube, and a portion of tix«d 

 alcali (I believe ^oda) in the wine glass. I repeated this 

 experiment more than thirty times with the same piece of 

 bladder, and had always the same result. Though I was j£ ^j^^ ^^j^ ^^ 

 at the time perfectly satisfied as to the production of an afforded by the 



acid and an alcali, I still thought, consistent with your *"*°^a^ ^"h- 



, . , , f , , , , stance, whence 



query mthe margm, that the bladder might have contri- comes the alca- 



buted to the production of the acid. But from whence h 



came the fixed alcali? a very ingenious chemist who has Fromtheglass? 



made the same experiment, says it comes from the glass 



vessel ; the thought appears very plausible, but I believe 



it is not a fact. 



Consistently with my promise to you, I have made the Experiment re- 

 experiment without the aid of either animal or vegetable peatcd without 

 substance to separate the two portions of water, and in- ^^ter^^*"** 

 stead of a wine glass, I made use of a platina cup. 



In order completely to exclude glass, I got a tube made with a tube of 

 of tobacco-pipe clay, being closed at the bottom, and ca- baked clay and 

 pable of holding water. The tube w^as burned in the ^a"^ ofplati- 

 same furnace with a quantity of tobacco-pipes and was 

 extremely hard. In the first place I suifered the pores of 

 the tube to be saturated with distilled water ; I then filled 

 it with the same and fixed it in a platina cup, also contain- 

 ing pure distilled water. The platina cup was placed 

 upon the copper end of the trough, a platina wire reach- 

 ing to the bottom of the tube was then connected with 

 the zinc end. In a little time bubbles were copiously 

 given out from the bottom of the cup, and also from the 

 H 2 wire 



