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of unnecessary dimensions to find an essential one, besides malang lmn liable to err. 
The draughtsman can more easily find such a dimension himself, and when once 
written on the drawing it is there for all tlie workmen requiring it. 
III. Make as few notes as possible on a drawing ; put dimensions or symbols 
instead. 
Such notes are easily missed and are seldom read. They belong more to speci- 
fications than to drawings, and where instruction lias to be given on drawings i\> 
can generally be given in a more readable form by symbols that catch the eye tlian 
by writing. 
By ‘• symbols n in this caao ia meant the usual marks adopted by different firms 
to indicate drilled holes, tapped holes, countersunk holes, holes left open, parts 
machined, steel, brass, etc. Such symbols are seen at a glance whilst a note re- 
quires moro or less study, is more verbose and is more easily missed by the workman. 
IV. Put all details and information required to make each article on^ne and 
tlie same drawing. 
To give one detail of an article on one drawing, another on another, and so on> 
requires the workman making that article to monopolize those drawings and pre- 
vents other workmen from using them for other parts of the work. The article 
itself is made under greater difficulties, as it confuses the workman if lie is required 
to pick out the details from several drawings and from among other details. 
V. Put all dimensions for each article as near together as convenient. 
Ifc wastes a workman's time to require him to hunt for the dimensions of tbe 
piece lie is making in the different parts of the same drawing. Thus if a web plate 
of a girder, say, be shown on tlie drawing the size may be given 8’ 6" x 普 " x 7’ 3" 
say， instead of showing the width in one place, thickness in another, and length in 
another. 
VI. Make thick lines and thick plain block figures. These are more easily 
seen and read by the workman in the shops. The blue prints from such tracings 
are more uniform and distinct. Such line 3 and figures are not so soon obliterated 
or soiled by the dirt of the shops. The figures should be plain ； the object being to 
make them easily readable, more useful than ornamental. Ornamental figures and 
lettering should be reserved for designs, estimates, etc. 
VII. Give inspector’s dimensions. 
These are generally main dimensions. In examining the work, and in the work 
when in place, the intermediate dimensions are not of much importance. For ex- 
ample, the dimensions used by an inspector examining the columns for a building 
are, say, distance from underside of bearing plate to bearing surface for shoe 
rafter or principal ； distance from underside of bearing plate to centre lino of hoi 掷 
for connecting floor beams to columns. The former dimension, being a main dimen- 
sion, would generally be given as required, but the latter is often to be obtained only 
by additions and subtractions, trying to the patience of inspectors or examiners i 11 
inclement weather. 
VIII. Instead of the term “ right hand，’’ use “ as shown, n and instead of “ 砂 
liautV’ use “opposite hancV’ 
