It may be well to inquire what are some of the causes which lead to an increase in the price, and to distinguish between those which are permanent and those which are ephemeral. The growth of book-collecting in the United States has had a most potent influence, and large purchases made for many years in England have drained off a large number of books, low priced as well as high priced, which will never return to this country. Another cause is the increase of public libraries in Great Britain, and when books are bought for these libraries they are permanently removed from the open market, as they are not when sold to an individual, because his library will most probably eventually come to the hammer. These two causes would be sufficient in themselves to permanently increase the price of scarce books, but there are still others to be mentioned. There has been of late years a greatly increased interest felt in the history of books--in printing, in binding--and increased knowledge has shown the great claims of a large number of books to a higher appreciation than hitherto. Then again, the class of the wealthy who can afford to collect choice libraries has largely increased; and lastly, the belief that the collecting of books is by no means a bad investment has not been without effect. This last point opens up a very interesting question in ethics, Should a collector look upon his collections as an investment? The late Mr. J. Hill Burton argues very strongly against this view in his “Book-Hunter.” He writes-- “The mercenary spirit must not be admitted to a share in the enjoyments of the book-hunter.... If [he] allows money-making, even for those he is to leave behind, to be combined with his pursuit, it loses its fresh relish, its exhilarating influence, and becomes the source of wretched cares and paltry anxieties. When money is the object, let a man speculate or become a miser.”... This is quite true, but we must remember that, after all, increased price is only an outward manifestation of increased public estimation, and it is always satisfactory to know that our opinion has been accepted by the public. The real point seems to be that the collector should use his judgment in respect to price, and not trouble himself whether the market value of individual books goes up or down, for he may be sure that if he buys wisely, the ups and the downs will balance each other. If a fair-sized library is purchased with judgment and knowledge, it cannot fail to become a profitable investment, because good books increase in value by reason of their companionship. All worthless books should therefore be ruthlessly weeded out. For instance, a library of 1000 choice books would probably sell for less with 500 books of little value added to them than if these were ruthlessly eliminated. Mr. Andrew Lang writes in his pretty little book, “The Library”--