A. 8. Thayer—Polarization of the Plates of Condensers, 209 
strength. In the case of condensers made with solid dielectrics 
the same diminishing current is observed, and the following 
experiments would seem to show that it might be due to an 
electrolysis or decomposition of the material separating the 
plates of tin-foile The experiments consisted in placing con- 
densers of various kinds in a circuit, through which a current 
was made to pass by two Bunsen’s cells, and noting their 
changes. The plates of the condensers were of tin-foil and had 
an area of about fifteen square inches. The experiments were 
as follows: — 
(1.) The dielectric used was a sheet of dry glazed paper. The 
condenser could not be charged so as to give a perceptible dis- 
charge. 
(2.) When a sheet of glazed paper, moistened with shellac, 
was substituted for the dry paper, the discharge was sufficient 
to send the light off the scale of the galvanometer, and con- 
tinued for some minutes. g 
(3.) Dry goldbeaters’ skin was used as a dielectric, and no 
deflection could be obtained. : 
(4.) The goldbeaters’ skin, when moistened with shellac, gave 
a slowly diminishing deflection. 
| (5.) The dielectric was made by flowing the surfaces of the 
plates with a solution of wax and gasoline, and a slowly di- 
minishing deflection was obtained. 
(6.) The condenser used in (4) was tried again after the shel- 
lac had dried and again gave a diminished deflection less than 
the first deflection. : ; 
(7.) The condenser used in (5), when tried again after a day 
or two, did not again give a deflection. 
(8.) Unglazed paper dry and oiled gave no deflection. 
(9.) Glazed paper oiled gave a very slight deflection, and the 
galvanometer needle immediately returned to zero. _ 
(10.) Glazed paper wet with water and covered with shellac 
gave the greatest deflection of all the dielectrics) The light 
Was sent completely off the scale and was only brought back 
by shunting the galvanometer. The discharge also continued a 
time 
tries was tested. The goldbeaters’ which had been covered 
send the light entirely off the scale. 
hat these alee directly go to show are, first, that 
condensers with moist dielectrics received a greater charge than 
Am, Jour. Sc1.—Turep Series, Vou. VIII, No. 45.—SePr., 1874. 
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