Many people buy things merely because they are cheap. No actual necessity dictated the purchase of the commodity, but “only 3s. 9d.” was irresistible! “If it is not useful now, it may be by-and-bye, besides Mrs. B—— has one,” is a sufficient argument to set off against that of economy, which would have us, as far as possible, gratify the demands of choice, but not create wants by the existence of supply. Now there is a somewhat similar tendency in mental economy. Subjects “made easy” are the snare of our nineteenth century enlightenment. Table-talk is a sign of our times! These are the days of wide spread but thin spread education. We must all know a little of everything. We must be able to converse rationally upon any subject, land tenure or ladies' gloves! and it consequently becomes a matter of some importance to have subjects “made easy.” We wish to get into the bowels of a science as we do into the bowels of a country, by train! Well, just as three and nine, and the fact that Mrs. B—— has one, tempted the purchase of the useless article, so the “made easy” and the small talk of a neighbour at dinner tempt to the acquisition of some very useless knowledge. And as it is true that purchases which are dictated by vanity and not by need do harm in trade, so do acquisitions of useless table-talk facts do harm in science. If a science is to have fair play, it is well for it if it does not become popular. Goethe somewhere says that when a man does a great thing the world seems to enter into a conspiracy to prevent him doing it again. It dines him and cheers him till he dies. He has only time to bow! So a science that is thought to have done some great thing becomes popular, and it is likely enough to die while the cheering lasts. A popular science, one that is “made easy,” is not likely to have much vitality in it. The intension of a science is in the inverse ratio to the extension.