and of obtaining supplies of water and of warm air. 295 
country, wishing to avoid this evil in 4 house which he was building, 
put together, in brick-work, out of doors, without mortar and with his 
own hands, the sides of the opening of a chimney, and _ also of its 
throat, according to Count Rumford’s latest plan; and then directed 
his workman to set up these bricks, with the addition of mortar, in 
his house, in the same form and order in which he had himself pla- 
ced them. This method being adopted for the chimnies of the whole 
building, not one room in his house was found troubled with smoke, 
on either floor ;_ provided that on the first lighting of any of his fires, 
apiece of inflamed paper was put on the top of the lighted fuel, to 
direct the course of the flame up the chimney. 
4. A safe place for ashes should be provided in every large inhab- 
ited building ; and a most rigorous attention should be paid to enforce 
the constant use of it—On the same principle, the yambs of a chim- 
ney should either be of marble, stone, or brick; or rest upon mar- 
ble, stone, or brick ; since if the lower part of these jambs be of 
wood, they may easily be set on fire by brands or embers, falling from 
the fire-place when no one is at hand to observe it. 
5. The method of warming rooms by heat conveyed into them 
through pipes, is, in some form or other, generally known in the 
United States; but proper principles do not appear to be every where 
well established respecting the subject ; as will appear from the fol- 
lowing remarks, which have in fact all been called for by errors on 
this head, which I have myself noticed as having occurred in prac- 
tice.—1. Where metallic tubes are employed on this occasion, they 
ought not to be so much heated, as to yield unhealthy fumes. 2. 
Pottery or brick work with cavities in it, however small, ought not to 
be employed for pipes ; lest offensive particles should lodge in these 
cavities, and contaminate the air as it passes through them. . 3. The 
air admitted into these tubes should be collected from a healthy quar- 
ter; and therefore not from cellars, or other damp or foul places ; 
nor from within a house, and especially if drawn from the level of a 
dirty or dusty floor or carpet ; but be obtained from the atmosphere 
at large by suitable means. 4. Methods for cleansing these air- 
tubes should be provided, lest spider’s webs, or other obstructions or 
impurities should collect there in the summer season, and produce 
inconveniences of different kinds. 
6. Nothing is said here of the newly invented modes of warming 
green-houses and hot-houses, by heat communicated to portions of air 
surrounding a set of metallic reservoirs, and corresponding metallic 
