A is a deal stand 12 by 3 inches; B is a hard-wood block firmly attached to A; C is a spring; D is an index-pillar; E is a scale-holder; F is a small bent pin to hold the spring steady while changing the scale-pan. The spring C should be very fine steel wire, bent over so as to form a loop near the index for E to hook into. The index is a slip of card set out with a fine pen. The scale-pan is of thin letter-paper, circular, and folded like a filter-paper, as indicated by the dotted line. With this minute fractions of a grain can be recognized.

Simple Balance