DUST AND FRESH AIR, 243 



What shall we do with crevices and cracks ? At first, I hoped 

 that narrow chinks might be ignored, on the principle that easy 

 passages of air through an ample screen would virtually stop off 

 currents through narrow spaces. In this I have been disappointed, 

 as, in some cases, a chink, though apparently narrow, has proved 

 too accommodating to the passage of air, and a more ready chan- 

 nel than the interstices of flannel. My rule now would be to close 

 or guard with filtering material every place where the door comes 

 into contact with its frame. 



The plan I have adopted with the doors of several cupboards 

 and closets is this to put strips of cotton velvet wherever the 

 door comes into contact with its framework. On the side where 

 the hinges are, the velvet is glued and sprigged to the edge of the 

 door ; on the other side and the top the velvet is fixed to the re- 

 bate against which the door presses. If the door belong to a 

 closet, and the bottom is not in close contact with the floor, a small 

 piece of flannel or cloth may be fixed along the inner side of the 

 bottom of the door, so as to form a curtain which closes the gap, 

 and filters any air that passes through. 



Such, then, are the principles which may guide us to a victory 

 over dust, and such are some of the details whereby we may work 

 out a method by which the victory is to be won. Do not suppose 

 that I claim to have completely conquered the enemy ; but a be- 

 ginning has been made, a beginning definite enough and assured 

 enough to encourage others, and especially architects, to study 

 the question and to make trials. If they will but work with de- 

 termination to conquer, they may confer upon the community a 

 most welcome amelioration of some of the smaller miseries we 

 have to submit to. 



And now let me venture to tell you what I should do were I 

 to construct an office in the center of a town. I should begin with 

 the fireplace. Let it be constructed on the principles I have been 

 teaching for the last ten years, and which were brought to a focus 

 in my lecture at the Royal Institution in 1866 principles which 

 are at last influencing the construction of fire-grates throughout 

 the kingdom. Shortly stated, they are : 



1. The back and sides of the fireplace to be fire-brick, built 

 solid. 



2. The depth of grate from front to back never to be less than 

 nine inches. 



3. The back to lean over the fire, not to lean away from it. 



4. The front bars to be vertical and thin, not horizontal and 

 thick. 



5. The ash-place under the grid to be made into a closed hot 

 chamber by a movable shield, named an " economizer." 



The effects of this construction are : 



