_Flues._--It will not be out of place to give a short treatise upon flues, as the flues in a residence govern the efficiency of the stoves and the comfort of the whole household. There is a common error in blaming the flue for all faults. It can be asserted that half the smoky chimneys are in no way the fault of the flue at all, and when a smoky chimney does exist, nearly every one flies to the chimney top with some device to govern the wind, and this in very many cases is a total failure. Flues are now generally constructed of two sizes, 9 in. and 14 in. A 7 in. flue would be sufficient for most warming stoves, but it has to be borne in mind that the accumulation of soot quickly diminishes the size internally, so that they are now never built less than 9 in. internal diameter. In building a residence, the following plan is often adopted when cheapness is not the primary object, that is, to build the usual square brick chimney, and within this to carry up a 9 in. flue of glazed earthenware pipe (drain pipe), and the space outside this pipe filled with concrete: this pipe flue is so easily cleaned and is much less quickly fouled, and improves the draught. The very general cause of smoky chimneys is that the chimney top is below the level of some adjacent building, tree, or other object that obstructs the free passage of the wind. In this instance the trouble is only experienced when the wind is in certain quarters, and sometimes this can be cured by a wind-guard or cowl (no particular make can be recommended, as their efficiency differs under different circumstances); but the only reliable remedy is to raise the chimney either by pipe or brickwork to the required height. The manner in which the annoyance is brought about is, that when the wind passes over the chimney top its progress is arrested by the higher object, and it may be said to rebound (the action is rarely quite alike in any two instances), causing either a portion of the gust to pass a short way down the chimney or to momentarily stop the up draught; this will be noticed by the gusts of smoke that come from the stove into the room.