Page:Outlines of Physical Chemistry - 1899.djvu/211

 APPARATUS AND METHODS

��e, and therefore this can be calculated in terms of e (the electromotive force of the standard element).

In practice, the resistance of a b must be fairly large. It generally consists of a board fitted with 21 metallic pins which may be connected above with a circuit and which are

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��or of 100 ohms, as indicated in fig. 43. The two pins marked are connected by a thick copper wire.

This total resistance of 1,000 ohms, as well as the element e, as shown in fig. 44. r is so modified that a Between the pins and there is no difference of potential,

��1 In order to do this a branch circuit containing an electrometer and a standard 1 volt cell is inserted between a and b, and the

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