17. Drawers and filing cases shall be numbered consecutively. Drawers
shall contain 100 sheets each, and filing cases 200 sheets each, and to
be fully indexed. Drawings shall be numbered by a number indicating both
drawer number and serial number in the drawer--thus, 7,604 is the fourth
sheet in drawer 76, etc.
18. Drawing numbers shall be checked off the index as required, and the
index posted up in uniform handwriting by the clerk.
19. Standard size drawings shall be kept in drawers and quarter and
eighth sheets in filing cases. All drawings shall be indexed by an index
sheet kept in each drawer or case.