1804. 
Polifhed tea urns may be kept boiling 
with a much lefs expence of fpirit of wine 
than fuch’as are varnifhed ; and the cleaner 
and brighter the difhes, and covers for 
difhes, which are ufed for bringing vic- 
tuals to table, and for keeping it hot, 
the more eff:Ctually will they anfwer that 
purpofe. 
Saucepans, and other kitchen utenfils, 
which are very clean and bright on the 
outfide, may be kept hot with a fmaller 
fire, than dich as are black and dirty ; 
but the bottom of a faucepan or boiler 
fhould be blackened, in-order that its con- 
tents may be made to boil quickly, and 
with a finall expence of fuel. 
When kitchen utenfils are ufed over a 
fire of fea-coal, or of wood, there will be 
no neceflity for blackening their bottoms, 
for they will foon be made black by the 
fmoke ; but, when they are ufed over a 
clear fire of charcoal, they fhould be black- 
ened with the {moke of a lamp, or coal- 
fire. 
It has been thought that brewers’ flats 
would anfwer the purpole of cooling li- 
quors better, if made of metal, than of 
wood: but a metallic furface is ill calcu- 
lated for expediting the emiffion of calo- 
rific rays. The thicknefs of the timber of 
which thefe tubs are commonly made, is 
favourable to a fpeedy cooling of. the 
wort; for when they are empty and 
cold, a great-part of the heat of the liquor 
is abforbed by the wood. 
Where metallic tudes filled with fteam 
are ufed for warming rooms, the external 
furface of them fhculd be painted, or co- 
vered with fome fubftance which facilitates 
the emiffion cf calorific rays. A cover- 
ing of thin paper will aniwer the purpofe 
very well, it it be black, and clofely at- 
tached to the furface of the metal with 
lue. 
4 Tubes defigned for conveying hot fleam 
from one place to another, fh:uld be co- 
vered up with 2 warm covering, or fhould 
be kept clean and bright. It might be 
worth while to gild them, cr to cover them 
with gilt paper, or tin foil, or fome other 
metallic fubftance which does not eafily 
_tarnifh with the air, The cylinders and 
principal fteam-tubes of fteam-engines 
might be covered, firftt with fome warm 
clozthing and then with fheet-brafs, kept 
clean and bright. The expence of this 
weaka would be repaid by a faving of 
uel, 
If garden walls, painted black, ac- 
quire heat faftcr, when expofed to the 
fun’s direst rays, they will likewife cool 
faer during the night, and gardeners 
Proceedings of Learned Societies. 
423 
mutt beft determine whether thefe changes 
of temperature are, or are not, favourabie 
to fruit trees. 
Black clothes are known to be warm 
in the fun; but they are far from being 
fo in the fhade, efpecially in cold wea- 
ther. No coloured clothing is fo cold as 
black, when the temperature of the air is 
below that of the furface of the fkin, and 
when the body is not expofed to the'ac- 
tion of calorific rays from other fub- 
ftances. 
The warmth of clothing depends 
much on the polz/b of the furtace of the 
fubftance of which it is made; hence, in 
chocSng winter garments, thofe dyes are 
to be avoided which tend moft to de- 
itroy that polifh: and as a white furface 
reflects more light than an equal furface, 
equally polifhed, of any other colour, 
there is reafon to think that white car- 
ments are warmer than any other, in cold 
weather. They are univerfally confi- 
dered as the cooleft that can be worn ina 
very hot weather, and efpecially when a 
perfon is expofed to the direét rays of the 
fun; and if they are weil calculated ta 
reflect calorific rays in fummer, they 
mult be equally well calculated to reflect 
thofe frigarific rays by which we are 
cooled and annoyed in winter. 
Garments of fur are warmer, in cold 
weather, when worn with the hair out. 
wards, than when it is turned inwards. 
Ts not this a proof that we are kept warm 
by our clothing, not fo much by confin- 
ing our heat, as by keeping off thole fri- 
gorific rays whichtend to cool us? The 
fine fur of beatts, being a highly polifhed 
fubftance, is calcuiated to reflect thole rays 
which fail on it; and if the body be 
kept warm, by the rays which pro- ' 
ceed from it being reflected back upon 
it, a fur garment would be warmeft 
when worn with the hair inwards; but 
if it be by reflecting and turning away 
the fiigorific rays from external and 
colder bodies, that we are kept warm by 
our clothes, we might expe& that a 
peliffe would be warmeft when wom 
with the hair outwards, as the Count 
fays, in fat, it is. 
The fur of feveral delicate animals be- 
comes white in winter, in cold countries 3 
and that of bears whici inhabit the polar 
regions is white in all (eafons. Thefe 
lait are expofed alternately, in the open 
air, to the molt intenfe cold, and to the 
continual action of the fun’s rays during 
feveral months. If it fhould be true that 
heat and cold are excited in the manner 
above defcribed, and that white is the co- 
lour 
