, 
S. Webber on Ventilation. 187 
ous defect, for if a chimney is used only with one or more of these 
Stoves, there is not sufficient warmth imparted to it in very cold 
weather, to prevent the pyroligneous acid generated in the com- 
bustion of the fuel, and passing in vapor by the edges of the 
damper, from being condensed against the inside of the chimney, 
Where it penetrates the mortar with which the bricks are laid, 
and acting upon the lime destroys the tenacity of the cement 
and passes through it into the rooms. An instance of this kind 
fell under the writer’s observation. The chimney in this case 
two flues, one from the ground floor, and one from the cham- 
ber above. Both were provided with air-tight stoves, which 
were managed with rigor according to the directions of the inven- 
tor. in the course of the first winter the pyroligneous acid began 
to show itself in the chamber, oozing through the plastering, on 
the sides of the chimney. where it was laid upon the bricks, and 
running in streams down to the floor. The same thing took 
place even more copiously in the loft above the chamber, and the 
fluid that ran down there, spread in. puddles over the ceiling of 
the chamber which intercepted it, and before spring made its way 
through the plaster of this ceiling in large patches, dripping copi- 
ously in various places, defacing and spoiling the carpets and 
furniture below, and rendering it necessary to set a number of 
Vessels on the floor to catch the dropping fluid, and prevent it 
from effecting the same destruction in the parlor below, which 
indeed, with all precautions that were taken, did not entirely 
escape. The chamber was rendered uninhabitable, and all that 
part of the house was troubled with “a most ancient and fish-like 
smell.” The use of the stoves as air-tights had to be entirely 
given up; and it was found necessary to rebuild the chimney 
ligneous vapor. 
d effectual. 
-pi a means of warming dwelling-houses 
has Se te ot ieee Samet so little favor, that it is hardly 
Worth while to say any thing about them. They are costly and 
troublesome, and have in themselves no means of changing the 
air. In establishments where steam is generated in large quan- 
other purposes, it may be profitable to employ waste or 
