20 LETTER concernine 
was an objection. Luckily the inhabitants of London 
have got over that objection, and now think it rather con= 
tributes to render their air falubrious, as they have had no 
general peftilential diforder fince the general ufe of coals, 
when, before it, fuch were frequent. Paris ftill burns wood 
at an enormous expence continually augmenting, the in- 
habitants having ftill that prejudice to overcome. In Ger= 
many you are happy in the ufe of ftoves, which fave fuel 
wonderfully : Your people are very ingenious in the ma~ 
nagement of fire; but they may itll learn fomething in 
that art from the Chinefe*, whofe country being greatly 
populous and fully cultivated, has little room left for the 
growth of wood, and having not much other fuel that is. 
good, have been forced upon many inventions during a 
courfe of ages, for making a little fire go as far as poffible. 
I have thus gone through all the common caufes of the 
fmoking of chimneys that I can at prefent recolle& as hav~ 
ing fallen under my obfervation ; communicating the re= 
medies that I have known fuccefsfully ufed for the differ- 
ent cafes, together with the principles on which both the 
difeafe and the remedy depend, and confeffing my igno= 
rance wherever I have been fenfible of it. You will do 
well, if you publifh, as you propofe, this letter, to add in 
notes, or as you pleafe, fuch obfervations as may have oc= 
eurred to your attentive mind; and if other philofophers. 
will do the fame, this part of fcience, though humble, yet 
of great utility, may in time be perfected. For many years 
paft, I have rarely met with a cafe of a f{moky chimney, 
which has not been folvable on thefe principles, and cured. 
by thefe remedies, where people have been willing to ap-. 
ply them; which is indeed not always the cafe; for many 
have prejudices in favour of the noftrums of pretending 
chimney-dodtors and fumifts, and fome have conceits and 
fancies of their own, which they rather chule to try, than 
to lengthen a funnel, alter the fize of an opening, or ad- 
mit air into a room, however neceflary ; for fome are as 
much 
* See Appendix, NO HL 
