505. Part I and each Section of Part II shall be divided into groups by kinds of register only, the number of groups in each part or section being identical with that of the kinds of register included therein. A separate series of numbers shall be given to the registers in each group. Enough space shall be allotted to each group to last for a number of years. Part II may be split up into several volumes if convenient, provided that the sections in any given volume shall be complete in themselves.
