The horizontal-bar method permits of placing figures so as to keep the decimal points in line, thus making it possible to add the whole column of figures relating to the various components.

The sector method is probably so widely known through presentation in exhibits, illustrations for popular magazines, etc., that it is more generally understood than any other niethod now in use. The more easy reading of the wedge or sector chart is, however, largely due to habit. If the horizontal-bar method of Fig. 1 were used as frequently as the sector method, it would be found in every way more desirable

COMPONENT PARTS

UOSTTHROUOH RADIATION, LEAKAGE OF STEAM ETC

LOST THROUGH UNCON5UMEO FUEL IN ASH

i.G5TJN THE FORM QF UNCONSUMEI? FUEL IN THE CfNDEfIS AND SPARKS

LOST (N OASES DISCHARGED FROM STACK

LOST IN VAPORIZING MOISTURE IN COAL

lOO 3

L. 50

than the sector method and would, in a very short time, become so well known that it would be read much more quickly and accurately than the method involving sectors.

In Fig. 4 a double scale is used by which the same data can be interpreted from two different standpoints. On the left the scale is given in millions of tons, and on the right in millions of dollars. The reader can interpret the chart from whichever standpoint he prefers. Though this chart is arranged vertically instead of horizontally, it really makes little difference which way the bars are placed. As a general thing, the horizontal arrangement lends itself more readily to the use of type so that the reader may read type statements without having to turn the book.