As stated in the preceding paper, the method of expressing, at sight, shillings, pence, and farthings as a decimal of a pound to 3 places has long been known. It is sometimes referred to as the actuaries' rule. According to De Morgan, it occurs for the first time in Kersey's edition of Wingate's Arithmetic, 1673 (p. 191). It is also to be found in Cocker's Decimal Arithmetic, 1685 (although in a form which is not quite accurate). In some of the earlier books the method of conversion at sight from the decimal form is given, but not vice versâ. It is now found in most modern text-books in one form or another.