If only one square of
chocolate is needed, draw a line across the two squares at the end, dividing them in halves. With a sharp knife, shave off the
chocolate until you come to the line. By this method there is no waste of time or material. If you want two or more squares, all that is necessary is, of course, to shave off until you come to the dividing line already there. The pound packages of Baker's
chocolate consist of two cakes, each of which has eight squares; so one of these squares is an ounce.
Source:
Miss Parloa's New Cook Book
