This summer ventilation is simple enough, and relates rather to comfort than to health.  The great question in building, for New England and similar climates, is, indeed, how to keep our houses warm, and, without great expenditure of fuel, have a constant change of air.  As you suggest, we have learned that wood costs eight or ten dollars a cord instead of the mere labor of cutting and hauling; hence we have shut the mouths of the old-time fireplaces, mouths that it would cost a fortune to feed.  We find the value of building-timber increasing every year; so we make thinner walls, lined outside and inside with paper, and have cold houses, no fresh air, anthracite coal, and disease.  Our grandfathers carried foot-stoves to church, where they sat and shivered, sometimes with the cold, sometimes at the doctrines.  We have warm air and stale.  Let us hope our children will have warmth and freshness for body and soul.  They, in their homes, had big fireplaces, loose doors, rattling windows, cracks in the walls, and as they lay in bed looked at the stars through the chinks in the roof, or felt the snow blow on their cheeks which were ruddy with health and vigor.  We have cylinder stoves, double windows, tight walls plastered and papered, and pale faces.

[Illustration:  GOOD OLD TIMES.]

Yet we build and furnish more wisely than our ancestors.  They ventilated because they couldn’t help it, couldn’t afford to build as we do, and could afford to burn an acre of woodland every year.

It is no light task you have set me preliminary to an honorable discharge.  Next to theology and government finance there is no subject on which the doctors differ and dogmatize as in this matter of warming and ventilating, most of them preferring that the universe should suffocate rather than their pet theories and furnaces be found wanting. (I’m not speaking of the theologians.)

Let me restate a few general principles, simple and obvious, yet so important that we must not risk forgetting them.  Air runs away with heat fast enough if allowed to move.  Confined it is a more effectual barrier than granite walls and plates of steel.  Hence the spaces in the wall should not extend its whole height unless for local ventilation.  Cut them off surely at each floor, and as much oftener as you please; also make the floors tight and warm.  Deafen with mortar if you can afford it, and do not allow the open spaces between the floor-timbers to extend unbroken through the house, or fail to close them between the rafters when the ceiling of the highest story is above the plates.  If you wish to warm the entire house, it will be good economy to lath and plaster along the under side of the rafters quite to the ridgepole.  Finally put on your double windows, and you are ready for winter quarters.