The walls of the night nurseries should be hung with a soft, general toned paper, varnished, so as to be sponged every week, or distempered all over, so as to be re-done at small cost at frequent intervals, for it is essential in the ordinary low-pitched upper rooms of town houses, generally devoted to nurseries, to wash out as often as possible, the peculiar stuffy bedroom atmosphere, which must be absorbed in the walls and ceilings of all low rooms. The tone of colouring or pattern on the walls should above all not be spotty or glaring, with strongly defined forms presenting nightmare effects to drive away sleep, or disturb our little ones in the hours of feverish unrest or sickness. But in the rooms they live in there is no reason why the “writing on the walls” should not be the earliest teaching of all that is beautiful in nature, art, or science, and by good illustrations of fairy lore and natural forms incline the thoughts of our children to all that is graceful and beautiful in nature or imaginative faculties. =Bells and Calls.=--No house can now be considered complete without it is fitted with call-tubes or bells, especially the latter. Call-tubes are more general in places of business, but they might often replace bells in a house with advantage to all concerned. The wires for bells are carried in tubes and boxes concealed by the finishing of the walls and skirting. These tubes are often of tinned iron or zinc, but they ought to be either of brass or strong galvanised iron. Zinc cannot be depended on: in some places it will moulder away; if not soldered, it opens, and the wires work into the joinings of the tube, which stops their movement. The old-fashioned system of bells is being largely supplanted by electric bells. _Electric Bells._--An ordinary electric bell is merely a vibrating contact breaker carrying a small hammer on its spring, which hammer strikes a bell placed within its reach as long as the vibration of the spring continues. The necessary apparatus comprises a battery to supply the force, wires to conduct it, circuit-closers to apply it, and bells to give it expression. [Illustration: 60. Battery.]