Now that the Infinitesimal Calculus is becoming part of regular school courses in Mathematics, the question of how the subject should be introduced takes on correspondingly increased importance. And the question is really of fundamental importance; for it is only when the average person, as distinguished from those of special aptitude for a subject, has to be considered, that we are driven back upon the necessity for a sound common-sense basis of theory. Recent articles in the Gazette are evidence of the growing interest in this question—discussion of the perennial issue of e being only a part of this wider inquiry.

Mr. G. Goodwill, in opening this discussion, said that in dealing with the subject of units in mechanics, it seemed to him to be a help, in the first place, to recognize that, in general, when expressing the value of any quantity, the unit employed belonged to one of two kinds, determined by the business in hand. It would be either (a) a unit represented simply by a well-recognised amount of the quantity itself, or (b) a unit which, in the simplest possible way, took account of the relations of the quantity with others with which they might at the same time be concerned.