for their particles by equation (29); and although in many instances it comes out as in electrolysis, in some instances it comes out from 20 per cent to 50 per cent too low, while in a few cases it is as low as one-fourth or one-fifth of the electrolytic value. Their procedure is in general to publish, not the value of
, but, instead, the value of
obtained from
by inserting Perrin’s value of
(