PREFATORY NOTE
The following Papers, though in their collected state they have a certain continuity of general subject, were written at different times and for different purposes. One is a modified reprint of an article which appeared in the Westminster Review as long ago as 1856. Seven of the others were contributed, at intervals within the last twelve years, to Macmillan’s Magazine, The Scotsman, or The Scots Observer, and are reprinted now with courteous permission. The remaining five are from manuscript of various dates since 1867, and are now published for the first time. An occasional small recurrence of fact or of phrase in the series may be excused in consideration that the Papers, thus written separately, may still be read separately.
Edinburgh: March 1892.