242 New Outlines of Chemical Philosophy, 



elements of the same kind repel, and contrary elements attract 

 each other. 



In a former paper I described some improvements that I had 

 made in electrometers, and in the modes of insulation. As these 

 improved instruments are highly necessary in conducting the 

 following experiments, 1 shall give an account of them here, to 

 save the reader the trouble of turning to my former paper. 



The electrometer which I make use of consists of an eight- 

 ounce phial with a stopple of sealing-wax fitted into its mouth; 

 through this stopple a piece of thin music wire passes, and ex- 

 tends down the axis of the glass about '2\ or 3 inches ; the top 

 of the wire standing 3 or 4 inches above the top of the phial. 

 The lower end of the wire is turned into a small ring, from 

 which two slips of Dutch metal are suspended; these are about 

 3-4ths of an inch in length and 1-lOth in breadth. The wire 

 is fixed into the stopple ; but the stopple itself is not made fast 

 into the mouth of the phial, but left so as to take out occa- 

 sionally. 



My insulating stands are made thus : — A piece of thermometer 

 tube five inches long is fixed to the bottom of a wine-glass (the 

 top being broken ot¥) with black sealing-wax, and a piece of a 

 stick of the same kind of wax, about an inch and an half in 

 length, is fixed upon the top of the tube. The top of the wax 

 being made soft, is formed into a projjer curve for glass tubes to 

 rest upon. This form is very convenient for making experi- 

 ments with electric columns ; but a circular piece of glass, hav- 

 ing its upper surface gilt with gold-leaf, fixed upon the top of 

 the waXj is more convenient for many other experiments'*'. 



Description of a Silver-leaf Electrometer. 



The object of this instrument is to investigate some properties 

 of M. De Luc's electric column. The electric machine collects 

 two elements by friction ; the Galvanic apparatus produces the 

 same two elements by a chemical process ; but the electric co- 

 lumn, by some unknown process, produces these elements with- 

 out either friction or chemical action. 



In fig. 1. ab represents part of a thermometer tube fixed into 

 the base of the instrument at a. be a cylinder of black sealing- 

 wax, rather thicker than the tube; and cd a strip of thin crown 

 glass, about an inch and a quarter in length and a quarter of an. 

 inch in breadth. To the lower end of this glass, a slip of silver- 

 leaff dp is fixed with gum-water; rq is another slip of silver- 



* See Phil. Mag. vol. xlvi. p. 210, for a further account of these insu- 

 lating stands. 



f Tlierf; is an article manufactured in imitation of silver-leaf, which 

 answers much belter for this purpose than that which i» genuine. 



kaf 



