\$S ACTION OF FHOSPHORTTS. 



out of the verlica! line by any a(lra6live power. This confirt:? 

 of a fine (ilk thread, ftretched in the fame plane as the filver 

 leaf. By means of the fcrew this thread may be moved both 

 horizontally and vertically, (o as to follow the movements of the 

 filver leaf. 

 Modcof ufing Every thing being thus arranged, make a communication 

 ih= mrtiunjeiit, \yy ^leans of conducting wires betwe'en a fmgle couple of me- 

 tallic diflts, or one conftitucnt part of a pile, placed on a plate 

 of glafs, and the inftrament, fo that one of the metals (hall 

 communicate with the top of the inftrument, and the other 

 v*ith the bottom. Then by means of a glafs handle fitted to it 

 move the plate flowly from one degree to another, and you 

 vrill find the leaf touch the ball with ordinary electricity, when 

 it is 60° or 80^ of the micrometer fcrew from the vertical plane, 

 in which the leaf filver refled before its communication with 

 the metallic diflvs. This diftance increafes for every pair of 

 dilks added; and as the ball remains fixed at the point to which 

 the fcrew has carried it, the motion of the inftrument may be 

 obferved with great accuracy. 

 Irs cTtrcroe fen- This inftrument is fo fenfible, (hat, if a flender glafs lube 

 5bihiy» l^g rubbed but twice, and brought near the apparatus, though 



feveral inches from its fummit, it pafTes through the wh'>!e 

 extent of its fcale. It is for this reafon the inventor calls it 

 a micro-ekBrometeri becaiife we can meafure only very weak 

 degrees of electricity with it. 



XXIV. 



ABion 6f Phofphorits on the Soluliom of Metals. By Mr. 



SCIINAUBERT *. 



PhofpTiorus ob- k-^AGEf had already obferved, that phofphorus precipitates 

 icrved to preci- j|^g fulphates of copper and of manganefe. After him 

 pitatc metals, by , ' , . , ^ ... . .. , , • , i • i 



Sag?, ITem.inri, IHemann J obtained a crvftallization ot hlver m the humid 



and Mis. Ful- y^,^y \yy n^eans of phophorus. Still more recently Mrs. Ful- 

 hiime. ^ • 



' * Van Mons's Jourfiol de Chim'iey Vol. Vf. p. 95. Abridged 

 from Goettling's Chemifches Tafchenbuch. 



■f Analyfe chbnique et Concordance des trois Regnes. 



+ Creir« Chemifcbe Annalen, 17S9, Tom. II. p. 323. 



^ hame 



