There is a noted aphorism of Cendillac, to the effect that the one sufficient rule for discovering the nature and properties of objects is to name them properly, as if, observes Mr. J. S. Mill, 'the reverse was not the truth, that it is impossible to name them properly except in proportion as we are already acquainted with their nature and properties.' Need it be added that this knowledge is only to be had by patient observation? * Mill Logic vol. l, p.7. To assist this habit, Dr. Watts recommends the thinker to ascertain if a given idea is clear and distinct, obscure and confused, learned or vulgar, perfect or imperfect, adequate or inadequate--true or false. 'View a subject, says he, as through a telescope, so as to command a clear view of it; examine its whole bearings as you look over a globe; consider it in its several properties--anatomise it as with a scalpel. Take cognizance of its various aspects as though inspecting it through a prismatic glass. Whenever we contemplate a single object in nature is obvious it must have duration, size, weight, form, colour, such qualities being essentially present in all adequate conceptions of physical phenomena.' It was objected to the 'Cricket' of Mr. Dickens, that his delineation of Bertha was wanting in truthfulness. The teachers of the blind who knew their nature could detect the departure from the reality of their habits in the sketch of Bertha. The study of the blind was necessary to insure success. We may not be able in any one book to give rules for the study of all subjects, but we may indicate that we ought not to speak of what we do not know, and that if we mean to introduce certain facts into our speech or writing, we should consult the records and experienee of those persons who are known to have written upon the subject, and follow the best directions they give, and we shall generally attain accuracy.