116 On the Marquis de Chabanne’s [Fun. 
of air, damps in bed-rooms, chills on coming into the staircase, or 
on moving from one room to another; and these are the causes of 
half the winter diseases of our climate. An invalid in a house so 
warmed and ventilated need scarcely regret the climate of Lisbon or 
Madeira. 
Tke new apparatus shuts up the chimney altogether, except the 
little tube of the stove where a stove is used. The importance of 
this effect in securing uniformity of temperature may need explana- 
tion to some. In our ordinary chimney there passes up not only 
the air which has fed the fire, and has been heated by it, but a much 
larger quantity which enters it between the bottom of the mantle- 
piece and the fire. It is this last abstraction which produces the 
powerful and dangerous draughts which we always feel tending 
towards the fireplace, and which causes the sudden fall of tempera- 
ture in a room when the door is left open fora minute. There 
passes off too, unfortunately, only the lower stratum of air into 
which the chimney opens, while the heated air above remains un- 
touched. . A common chimney, therefore, in addition to the great 
draught produced by it, must necessarily maintain a heated and im- 
pure atmosphere above the level of the mantlepiece, surrounding the 
_ heads of the company, and being breathed by them; and below, a 
stratum of cold air moving towards the fire, pure indeed, but an- 
swering only the purpose of chilling dangerously our feet and nether 
bodies which are immersed in it. . 
6. The Purity of the Air—Man’s existence depends imme- 
diately upon the agency of the air, of which he consumes in breath- 
ing the vital principle. Deprive him of air but for a minute, and 
he becomes senseless, and dies. Confine him to a small quantity 
without change, and the same effect as certainly follows. Change 
the air in any known way, or his body in its disposition to be affected 
by it, and the most striking results follow. With all this before us, 
it is singular that many of the certain consequences of breathing 
vitiated air should so long have been attributed rather to other causes 
than to the real one. While we see gaol, ship, and hospital, fevers, 
arising as necessary consequences where many persons breathe toge- 
ther in confined places, we have often attributed to want of exercise 
only the consumptions, debility, paleness, and premature death, of 
persons of sedentary habits or employments. Persons who are 
much abroad in the open air, and those who are not, may in all 
cases by their appearance be very easily distinguished from each 
other ; and it is only among the former that we meet with longevity 
and vigorous health. By the plan of ventilation now proposed, it 
is evident that the air in a small study or bed-room can never cease 
to be as pure as under the open sky. 
The proposer of these improvements, the Marquis de Chabannes, 
has received a patent, which ensures him some advantage from their 
adoption. His name will suggest a reflection, which has already 
often been made, that England has not only the honour of making 
the most important discoveries herself, but it is to her also that in- 
ee a 
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