It is a mistake also to imagine that keeping the best bound volumes in a glass doored book-case is a preservative. The damp air will certainly penetrate, and as the absence of ventilation will assist the formation of mould, the books will be worse off than if they had been placed in open shelves. If security be desirable, by all means abolish the glass and place ornamental brass wire-work in its stead. Like the writers of old Cookery Books who stamped special receipts with the testimony of personal experience, I can say "probatum est." CHAPTER III. GAS AND HEAT. WHAT a valuable servant is Gas, and how dreadfully we should cry out were it to be banished from our homes; and yet no one who loves his books should allow a single jet in his library, unless, indeed he can afford a "sun light," which is the form in which it is used in some public libraries, where the whole of the fumes are carried at once into the open air. Unfortunately, I can speak from experience of the dire effect of gas in a confined space. Some years ago when placing the shelves round the small room, which, by a euphemism, is called my library, I took the precaution of making two self-acting ventilators which communicated directly with the outer air just under the ceiling. For economy of space as well as of temper (for lamps of all kinds are sore trials), I had a gasalier of three lights over the table. The effect was to cause great heat in the upper regions, and in the course of a year or two the leather valance which hung from the window, as well as the fringe which dropped half-an-inch from each shelf to keep out the dust, was just like tinder, and in some parts actually fell to the ground by its own weight; while the backs of the books upon the top shelves were perished, and crumbled away when touched, being reduced to the consistency of Scotch snuff. This was, of course, due to the sulphur in the gas fumes. I remember having a book some years ago from the top shelf in the library of the London Institution, where gas is used, and the whole of the back fell off in my hands, although the volume in other respects seemed quite uninjured. Thousands more were in a similar plight.