81. Class ascertained by description.

81.     Class ascertained by description.

A limitation to a class of persons answering a given description, of which class any member may possibly have to be ascertained or be ascertainable for the first time at a period exceeding the perpetuity period, is wholly void, even as to those members of the class who are ascertainable within that period1, as the quantum of interest of those members is not ascertainable2.

Where the class is defined as a part of a larger number of persons (as where the class is those of the children of a named person who attain