424 Experivienls in Voltaic Eleclfkity. 



interrupted; but when Ijiokcji by Lane's electrometer, gas was 

 given out Ijy both wires, accompanied with a torrent of sniiill 

 sparks, and a cloud of oxide rising between the positive wire and 

 the globide. This current of electricity, when not intercepted, 

 had power to tinge litmus paper red and turmeric paper brown 

 at the respective positive and negative wires — a few turns of the 

 winch made this visible. The above-mentioned effects took 

 place when the globule was subjected to the Voltaic action un- 

 der double distilled rain-water, but in a mucli less degree, as the 

 pure water was witii dif/iculli/ decomposable with a hundred 

 four-inch plates highly charged. This appeared to arise from 

 its being so imperfect a conductor in consequence of being freed 

 from acid : indeed, a successive minute stream of sparks attended 

 with an electrical snajjping, took ])lace from one wire to the 

 other, and not much gas was discerni!)le from cither ; but the 

 moment a drop of acid was let fall into the water, the sn;ipping 

 ceased, and gas was most co])iousiv disengaged fioni both wires. 

 No motion could bo given to the mercnrv, until the water was 

 slightly acidified. If the sulphuric, nitric, or solution of citric 

 acid are added to the distilled water in anv quantity, the gas is 

 abundantly increased; but the mercuiv is not easilv fixed nor set 

 in motion as with common water, and the surface v/hen in con- 

 tact with tlie negative wire is covered with bubbles of hydrogen 

 rising from every part of the globule. Under water impregnated 

 with carbonic acid gas or acetic acid much the same effects take 

 place as under common water, except t'lat w.ove gas is liberated; 

 but with the acetic acid less gas is liberated than with the car- 

 bonic acid, and the globiile is not so easily fixable. When the 

 pure water was acidified u'ith either the muriatic or oxalic acids, 

 a most singular effect took place on connecting the globule with 

 the positive wire — it lost all fiuidity in a moment, and could be 

 drawn out in very long fibres as small as the finest hair — with 

 the muriatic acid the mercury in contact with the positive be^ 

 came partially coated with a very beautiful deep-blue coat, oc^ 

 casionally mixed with a fine orange-coloured oxide ; when 

 touched by the negative the coloured scales fell off in a moment, 

 and the metal appeared perfectly brilliant — the o,\aiic acid pro- 

 duced no colour. This is a beautiful experiment. Under so- 

 lution of boracic acid in alcohol, tlie mercury was not so friable 

 nor capable of being set in motion as under water. A singular 

 smell was emitted when the trough was highly charged. With 

 all these acids gas was liberated by both wires, whether in con- 

 tact Vvitli the glob'de of mercury or not. When the piatina 

 wires are plunged in linuid ammonia, and held even an inch 

 asunder, the most violent motion is communicated to the glor 



bule. 



