Exptrinunts with a new EkQrical or Galvanic apparatus. 183 



clock ftanding in the room. The product of gas, during the whole two hours and a half, 

 was two-thirtieths of a cubic rnch. It was then mixed with an equal quantity of common 

 air, and exploded by the application of a lighted waxed thread. 



It might feem almoft unneceflary to have reverfed the order of the pile in building up, as 

 reverfing the tube muft have anfwered exactly the fame purpofe. We chofe, however, to 

 do this, and found that when the zinc was at the bottom, its effe£ls were reverfed, that is to 

 fay, the gas ftill came from the wire communicating with the filver, &c. 



We had been led by our reafoning on the firft appearance of hydrogen to cxpeft a dc« 

 compofition of the water ; but it was with no little furprize that we found the hydrogen 

 extricated at the contaft with one wire, while the oxigen fixed itfelf in combination with 

 the other wire at the diftance of almoft two inches. This new fa£t ftill remains to be ex- 

 plained, and feems to point at fome general law of the agency of eleftricity in chemical 

 operations. As the diftance between the wires formed a ftriking feature in this refult, it 

 became defirable to afcertain whecher it would take place to greater diftances. When a 

 tube three quarters of an inch in diameter, and thirty-fix inches long, was made ufe of, 

 the effefl failed, though the very fame wires, inferted into a ftiorter tube, operated very 

 brifkly. The folicitation of other objcds of enquiry prevented trial being made of all the 

 various intermediate diftances ; but from the general tenor of experiments, it appears to 

 be eftabiiflied, that this decompofition is more efFedual the lefs the diftance between the 

 wires, but that it ceafes altogether when the wires come into contaft. 



May 6. — Mr. CarJifle repeated the experiment with copper wires and tin£lure of litmus. 

 The oxidating wire, namely, from the zinc fide, was the loweft in the tube; it changed 

 the tinfture red in about ten minutes as high as the upper extremity of the wire. The 

 other portion remained blue. Hence it feems either an acid was formed, or that a portion 

 of the oxigen combined with the litmus, fo as produce the efFefl of an acid. 



It may be here offered as a general remark, that the eledlric pile with card, or with 

 woollen cloth, continues in order for about two days, or fcarcely three ; that from a feries of 

 glafles fet up by Mr. Carlifle, as well as from the pile itfelf, it appears that the fame 

 procefs of decompofition of water is carried on between each pair of plates, the zinc being 

 oxided on the wet face, and hydrogen given out ; that the common fait is decompofed, 

 and exhibits an efHorefcence of foda round the edges of the pile, extruded, moft probably, 

 by the hydrogen : and that on account of the corrofion of the faces of the zinc, it is 

 neceffary to renew them previous to each conftrudtion of the pile. This may be done by 

 fcraping or grinding. I found it moft convenient to lay the piece in a hole in a board, and 

 give it a ftroke with a float file, or file of which the teeth are not crofled. It might, 

 perhaps, be lefs troublefoihe to clean them with diluted muriatic acid ; but this I have 

 not tried. 



As the ample field of phyfiological refearch to which Mr. Carlifle's attention is direfted, 



and the multiplicity of my own avocations, rendered it lefs convenient for us to purfue 



3 our 



