After all the assistance given to such equations between different
times or different places by Sir George Shuckborough's tables, and
other similar investigations, it is still a very difficult problem,
complex, and, after all, merely tentative in the results, to assign
the true value in such cases; not only for the obvious reason, that
the powers of money have varied in different directions with regard
to different objects, and in different degrees where the direction
has on the whole continued the same, but because the very objects
to be taken into computation are so indeterminate, and vary so
much, not only as regards century and century, kingdom and kingdom,
but also, even in the same century and the same kingdom, as regards
rank and rank. That which is a mere necessary to one, is a
luxurious superfluity to another. And, in order to ascertain these
differences, it is an indispensable qualification to have studied
the habits and customs of the several classes concerned, together
with the variations of those habits and customs.