594 TRANSACTIONS OF THE 



only necessary to make them air tight cells. How to do this is 

 the practical question. 



It is common in the Eastern States to cover the frames of 

 wooden buildings with rough boards, and to place clap boards 

 outside of them. Though this affords but an imperfect barrier 

 against piercing winds, it forms a tolerable shield against still cold. 

 A better practice prevailing in this vicinity, is to fill in with 

 bricks and mortar between the parts of the frame; this makes 

 one thickness air-tight, or nearly so, but there is often great 

 carelessness in the finish of the interior plastering. A better plan 

 than the first named is to lath and plaster roughly but tightly 

 upon the back of the clapboards, and in either case care should 

 be taken that no open spaces are left at the floors and ceilings, 

 and a means of circulation afforded to the air confined between 

 the two shells of the wall. Filling in the whole space, several 

 inches in depth, at each floor, not only accomplishes this purpose, 

 but is an obstacle to the rats and mice, who may often, if allowed 

 free scope, break up the best laid plans for isolation and venti- 

 lation. 



In brick walls built with hollow spaces, the advantages of 

 their form are often lost by making cold air flues of the air cells, 

 thus reducing the inner wall to the condition of an exterior one, 

 the air space and outer wall being rendered useless as protectors. 

 As already mentioned, the leaders or bond bricks needed in such 

 work materially interfere with the perfect results which such an 

 arrangement, well carried out, seems to promise. 



Furring, or setting of the lathing at a little distance from the 

 masonwork, serves by far the best purpose of all the plans yet 

 devised, and is based on the most scientific principles. The ob- 

 jections to this method, are the additional expense of the furring 

 and lathing, and danger from fire. These, however, are difficul- 

 ties which may be overcome, and at any rate are not properly to 

 be considered in this connection. 



If what has here been advanced is true, the perfect protection 

 of buildings from the weather, is an easier matter than it is often 

 made to appear. The thickness of the air space is nearly or quite 

 immaterial. The conducting properties of the material composing 

 the cell make no diSerence. Two thickness of pasteboard fitted 

 tightly into an aperture of a wall, so long as they remain in good 

 condition, would be as effectual as solid blocks of stone of the 

 most massive size. This may seem extravagant, but facts will 

 show its truth. 



