mere CofitaB of cofiiuElhig Suhjlaficcs. 295 



forty or fifty couples of metals, which gives fliocks more than 

 moderate to both the arms of one perfon, is capable of giving 

 fenfible fliocks alfo to feveral perfons, holding each other by 

 the hands (fafficiently moid) fo as to form an uninterrupted 

 chain. 



I fliall now return to the mechanical conftruftion of my 

 apparatus, which is fufceptible of feveral variations, and de- 

 fcribe not all thofe which I have invented or made, either on 

 a fmall or a large fcale, but onlv a few, which are either cu- 

 rious or ufeful, which exhibit fome real advantage, as being 

 eafier or iooner conftru6led, and which are certain in their 

 effects, or can be longer preferved in good order. 



I fhall begin by one which, uniting; nearly all thefe advan- 

 tages, differs moft in its figure from the columnar apparatus 

 above defcribed, but which is attended with the inconveni- 

 ence of being much more voluminous. This new appara- 

 tus, which I fhall call a couronnc de tajj'cs (a chain of cups), 

 is reprefented Plate Vf II. fig. i. 



I difpofe, therefore, a row of feveral bafons or cups of any 

 matter whatever, except metal, fuch as wood, fliell, earth, 

 or rather glafs (fmall tumblers or drinking glaiies are the 

 mort convenient), half filled with pure water, or rather fait 

 water or ley : they are made all to communicate by forming 

 them into a fort of chain, by means of fo many metallic arcs, 

 one arm of which, Sa, or only the extremity S, immerfed 

 in one of the tumblers, is of copper or brafs, or rather of 

 copper plated with filver; and the other, Za, immerfed into 

 the next tumbler, is of tin, or rather of zinc. I fliall here 

 ohferve, that ley and other alkaline liquors are preferable 

 when one of the metals to be immerfed is tin : fait water is 

 preferable when it is zinc. The two metals of which each 

 arc is compofed, are foldered together in any part above that 

 which is immerfed in the liquor, and which mtift touch it 

 with a furface fufficiently large : it is neceflary therefore that 

 this part lliould be a plate of an inch fquare, or very little 

 lefs ; the reft of the arc may be as much narrower as you 

 choofe, and even a fimple metallic wire. It may alfoconfifl 

 of a third metal different from the two immerfed into the 

 tumblers, *ucc the adUoii on the- electric fluid which refults 



from 



