Twenty-second. See that the drawings scale, and, if they do not, make a note saying that the dimensions written on the drawings are to be followed in preference to the scale where there is any discrepancy between the two.

Twenty-third. In short, check over all details, dimensions, sections, and notes given on the drawings, so as to make sure that everything is in strict accordance with the specifications and with the data furnished for the structure.

SHOP DRAWINGS.

First. Make sure that the sections and details conform in every particular with those given on the general detail drawings and stress-diagrams, excepting in minor points, where slight changes may be made to facilitate the work in the shops, provided, of course, that such alterations do not in any way impair the strength, durability, or appearance.

Second. Check over all field connections to see that there are no rivets which are so located that they cannot be satisfactorily driven in the field.

Third. See that all members have proper clearances at panel points, and that all rivet-heads, wherever necessary to provide such clearances, are countersunk or flattened.

Fourth. Check over all lengths of members and rivet-spacing for field connections to make sure that the holes will match in the field.

Fifth. Check over all bills of material to see that the proper number of pieces have been ordered, and that they are of proper sections and lengths.

Sixth. Always have the shop-drawings sent to the office in duplicate, and check up the two sets, retaining one set in the office and returning the other set with corrections or approval marked thereon. Where drawings are returned to shops with corrections marked on them, revised prints must be sent for approval before the work is put into the shops.

It is often necessary to make changes on a tracing, and in doing so great care should be exercised, otherwise a drawing which has cost considerable time and money may be ruined.