It is very curious that architects should set themselves to work to violate first principles, and so involve us in these troubles. In the first place, to ensure that a chimney shall not smoke, the flue must be made large enough to carry the smoke. This is a principle very generally neglected. Next it is necessary that the chimney should not have a flat top, for then the wind beats against the broad surface, and, of course, prevents the smoke from rising, and much of it is deflected down the flue.
What our forefathers did was to reduce the top to a thin edge that could not arrest and drive the smoke down, but would, on the contrary, assist it in rising. Or else they covered over the orifice with a roof, open at the sides, that prevented the wind from descending, and enabled the smoke to get away whichever way the wind blew.
In order to illustrate what I mean, I have simply taken my pencil and gone outside my house, and have drawn an old and a new chimney-top.
The chimney-piece or overmantel is the reredos of the family altar, and should
