Miscellaneous papers . sec2. As regards the method of experimenting I may mentionthe following. The metal plate used was the silvering of aglass plate, produced by Liebigs process. Its form is shownin Fig. 17 ; the distance AB was about 45 mm., the distanceGD 25 mm. The leads were soldered to small platinumplates, and these were pressed into contact with the silveringby small screws penetrating the glass plate; a layer of gold-leaf was introduced between the silvering and the plates, so asto produce a more uniform contact. The electrical resistancewas at first 5*4 Siemens units in the directio
Miscellaneous papers . sec2. As regards the method of experimenting I may mentionthe following. The metal plate used was the silvering of aglass plate, produced by Liebigs process. Its form is shownin Fig. 17 ; the distance AB was about 45 mm., the distanceGD 25 mm. The leads were soldered to small platinumplates, and these were pressed into contact with the silveringby small screws penetrating the glass plate; a layer of gold-leaf was introduced between the silvering and the plates, so asto produce a more uniform contact. The electrical resistancewas at first 5*4 Siemens units in the direction AB, and 3*5Siemens units in the direction GD. From some unexplainedcauses these resistances diminished in time, and after someweeks were found to be 4*8 and 3*1 Siemens units the ratio of these resistances and from special experi-ments, it followed that the resistances of the contacts at theleads did not amount to any appreciable fraction of the whole KINETIC ENERGY OF ELECTRICITY IN MOTION [II] 139. ^a® Fig. 17. resistance. The system was adjusted to bring the needle tozero by scraping off the silver at various points of the edge;but as a sufficiently accurate adjustment from various causescould not be permanently obtained, shuntsof several hundred Siemens units resistancewere introduced between A and C andbetween C and B, and by their adjustmentthe needle could always be brought to zero,in so far as that seemed desirable. The glass plate was fastened to a brassdisc so as to permit of a rapid rotation;the silvered surface faced the disc, andwas only separated from it by the thin-nest possible air film. The disc itself wasat the end of a horizontal steel spindle,which was set in two bearings in such a way that its twoends were free. The connection to the galvanometer wasmade at the glass plate itself; that to the battery, whichsupplied the current, at the other end of the spindle; theconnections to the points A and B were formed by the spindleitself and by
Size: 1383px × 1808px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectphysics, bookyear1896
