ACDB  =lp, where l denotes the length c D of the See also:

• ROD (O.E. rodd, probably related to Norw. rudda, stick, rodda, stake)
• ROD, EDOUARD (1857-1910)

rod and p the distance AB through which it has been moved . This distance, as measured by the See also:

• ROLLING

rolling of the See also:

• WHEEL (0. Eng. hweol, hweohl, &c., cognate with Icel. hjol, Dan. hiul, the Indo-European root is seen in Sanskrit chakra, Gr. r in Aos, circle, whence " cycle ")
• WHEEL, BREAKING ON THE

wheel, which acts as a curvometer, will be called the " See also:

• ROLL (O. Fr. rolle, roulle, mod. role, Lat. rotulus, dim. of rota, wheel)
• ROLL, ALFRED PHILIPPE (1846– )

roll " of the wheel and be denoted by w . In this See also:

• CASE
• CASE, JOHN (d. 1600)

case p =w, and the See also:

• AREA

area P is given by P =wt . Let the circumfer- A ence of the wheel be divided into say a See also:

• HUNDRED

hundred equal parts u; then w registers the number of u's rolled over, and w therefore gives the number of areas lu contained in the rectangle . By suitably selecting the See also:

• RADIUS

radius of the wheel and the length 1, this area lu may be any convenient unit, say a square See also:

• INCH (O. Eng. ynce from Lat. uncia, a twelfthpart; cf. " ounce," and see As)

inch or square centimetre . By changing 1 the unit will be changed . Again, suppose the rod to turn (fig . 7) about the end .