electromagnetism - Question about units of mass, $M = (L^{3})(T^{-2})$?

In section 5 of the "Preliminary: On the measurement of quantities" chapter (page 3) in "A treatise on electricity and magnetism" Maxwell uses, total length, $s=mt^{2}/{2r^{2}}$to show that $m=2sr^{2}/{t^2}$ is in units of Length cubed over Time squared.

This is the first I have encountered this way of looking at mass and am wondering:

1. Is this just per-relativity nonsense?


2. Does mass being "length cubed over time squared" have any meaning?