pictures.

Before charts are sent to an engraver to

have plates made for printing it is wise to

have each chart run the gauntlet of a series of

questions, so that the time of the person doing

the checking may be saved and also that the

points more frequently overlooked may be

thoroughly considered in each case. Below are

given a series of questions which may be found

convenient to anyone having charts to prepare.

This list is not by any means complete, and

the questions are given here as general suggestions only. The person checking a chart simply

reads the questions one by one from the book, and then carefully observes the chart to see whether it comes up to the standard. Whenever possible it is well to have the chart

mm^

% .w^ 'mm.

Courtesy of the Grolier Society

Fig- 255. An Optical Illusion

checked by some The columns appear bent The

•^ left-hand pair seem closest

person other than ?t the ends, while the right

hand pair seem closest at the center. The sides of the columns are really straight and parallel

the one who drew it. In every editorial office the

fact is recognized that one proof-reader will find important errors that were overlooked by another reader equally expert. Further, a mind much occupied with an idea may often fail to see important gaps in its statement, verbal or graphic, until perhaps they are noted by someone less familiar with the subject. Two points of view are always better than one.