The escape of the vitiated air requires less consideration. If the ceiling of the room be flat, with another room above it, the upper part of each window, in the shape of a narrow slip, might be made to act as a sort of safety-valve; but if the windows are on one side only, corresponding openings should be made on the opposite side, so that there would almost always be, more or less, a leeward opening. A vaulted ceiling, without any other room over it, seems to be the most desirable form, as the vitiated air would rise and collect towards its centre, where there could be no counter-current to impede its egress. It is the union of those two objects, the admission of fresh air and the riddance of the vitiated air, skilfully and economically effected, which forms the circle of the science of ventilation. I have restricted myself to the means of _ventilation_, which is requisite at all seasons of the year, but am quite aware that _warmth_, or a temperature above that of the external air, is sometimes indispensable to health and comfort, and therefore to the free exercise of the faculties. I believe, however, that the means proposed for the admission of fresh air might also be made available for the admission of heated air, and that either description of air might be admitted independently of the other, or both descriptions simultaneously. A vast increase of reading-rooms, lecture-rooms, and school-rooms, may be safely predicted, and as the due ventilation of such rooms is a project of undeniable importance, I hope this note, eccentric in form, but earnest as to its purpose, may invite the remarks of others more conversant with architecture and physics--either in correction, or confirmation, or extension, of its general principles and details. BOLTON CORNEY. The Terrace, Barnes, 28th April, 1854. * * * * * THE HOUSE OF RUSSELL, OR DU ROZEL. At a time when the readers of "N. & Q.," and the world at large, have been hearing of the gift of a bell to a village church in Normandy, so pleasantly and readily made by the princely house of Russell, far exceeding the modest solicitation of the cure for assistance by way of a subscription, in remembrance of the Du Rozels having left their native patrimony in France to share the fortunes of the Conqueror in Old England, the following particulars may not be uninteresting.