50 
THE COTTAGE GARDENER. 
OcTonER 28. 
through the broken panes beneath, and affords strong 
evidence of the check to tlie escape of heat which a 
second glass affords. Let it not bo supposed, however, 
that there ought to be any opening in tbe inner glass 
for the purpose of admitting warm, air from the bed 
between the two glazings. So far is this from being 
desirable, that the panes of glass, both in the lower and 
upper glazing, should be puttied oven between the laps, 
in order that they may be rendered as nearly as possible 
air-tight. 
The philosophy of double-glazing shows that its power 
to protect from frost depends upon that tightness, for it 
is only air confined, or kept quiet, that is a bad con¬ 
ductor of heat, and air in motion carries off heat very 
rapidly. The most intense cold in calm weather was 
not a cause of suffering to Captain Parry’s men when 
properly clothed at the North Pole, but the same 
degree of cold, when the wind was high, was not 
endurable, although the thermometer showed there was 
no lower degree of temperature—the air in motion carried 
olf the heat faster, '.fhe same principle is in operation 
when a wet finger is held up to detect which way a 
current of air is passing, by its rendering one side of the 
finger colder than the other. 
It is on the known fact that air is a non-conductor of 
heat, that double windows are employed in Russia to 
exclude the cold, and in the West Indies to exclude the 
heat. This is no anomaly, for to exclude cold is only 
another mode of expressing what is intended when wo 
speak of keeping in the heat. In Russia they have to 
keep the room’s heat from escaping into the air, and in 
the West Indies they have to keep the air’s heat from 
getting into the rooms. 
In double-glazing our garden frames, we have the 
same object in view as they have in Russia; and if the 
frames had double boards, or tbe pits double walls, as 
some ice-bouses have, the cold could be excluded, so as 
to protect many more plants than at present we are 
able to carry through the winter without the aid of 
artificial heat. 
Another advantage attendant upon double-glazing, 
besides those mentioned by our corrcspoirdent, is the 
j prevention of “ drip ” within the frame, pit, or house, 
j 'this is occasioned by the warm air, which contains 
j moisture in proportion to its warmth, coming in contact 
with the cold glass, and there letting drop all the 
moisture it is not capable of holding at the lower tem¬ 
perature to which it was cooled by the glass. When 
the difference between the temperature of the glass and 
that of the air is gr-cat, the moisture is deposited, or let 
drop, in such quantity on the glass, that the moisture 
trickles down and forms “ the drip.” Now, double- 
glazing would jn-cvent there ever being so great a 
difference between the temperature of the inner glass 
and tire temperature of the air in the house, as to cause 
such a sufficient dejrosition of moisture as to form 
“ the drip.” 
COVENT GARDEN. 
Some of our readers will be disposed to doubt the 
correctness of oirr observation, and the authority of these 
“city articles” of ours, when they see in Covent Garden 
fruits purporting to be varieties which we said two or 
three weeks ago were, over for the season. But this is 
no uncommon occurrence; such modes of imposition 
having been practised ever since we have known the 
market, and, for ought wo know, one which boasts of 
as great antiquity as that which we exposed last week 
in reference to the .Elder berries. It may be laid down 
as a general rule, that whatever kind of fruit you ask 
for, you can have it. Jargonelles at Christmas, or even 
at Easter; Brown Bourros all the year round; Ribston 
Pippins; and “fine Burgamys,” are among the 
leading articles with these very accommodating traders. 
Our readers must, therefore, be on their guard how 
they receive the assurances, and 2 ffftce too much confi¬ 
dence in these indis'iduals. It would be wrong, how¬ 
ever, to say that there is no confidence to be 2 >laccd in 
nny of the fruiterers, for we know that there are some of 
them who are of the highest respectability and integrity, 
and who woidd scorn to be concerned in such jrractices. 
Ekuit. —There is still a continued abundant supjily 
of Ai’ei.Es, and at a somewhat advanced juice; some 
sorts having made as much as 7s. (id. per bushel. The 
general belief is, that Apples are a very short crop, and 
will, before the season is much farther advanced, be 
less ifientiful than they now are. The sorts which have 
been most jjlentiful during the week arc — llihston 
Pippins, P/Ienhehn Oramje, a fine aj) 2 )le, but, gencrallj' 
speaking, not so large this season as we have observed 
it. The Nonesuch, Winter Strairherry, and Ileauty 
of Kent, are among the leading sorts, as well as a few 
parcels of Enperor Alexander. In our rejiort of the 
week before last, our printer’s devil, who, like all other 
devils, is always up to some mischief, made us say there 
were Golden and Winter I’earmain’s in that week’s 
supply, whereas, in “ the cojiy,” we only mentioned the 
Golden Winter Pearmaiu. 'The Winter Pcarmains, 
so far from being in the marlmt, are hardly gathered 
yet. This Golden Winter Pcnrniain is by some called 
“ King of the Pippins”—a title given to it by a London 
nurseryman, who, either for the purpose of deceiving 
his customers, or with the view of retaining the sale in 
his own hands, apjffied to it this high-sounding name. 
Of Pears there has been an abundance, particularly of 
Marie Louise, which has now become so common as to 
bo met with on almost every frnit-stall in the streets. 
The Bishop's Thnmh is also very jfientiful, and we ob¬ 
served one or two parcels of the very old-fashioned 
Messire Jeane, which is one of those obsolete French 
pears that have been disiJaccd by the now Flemish 
varieties. In the centre arcade wore some of tho linest 
Vuchesse d' Angoulernesv/e have ever seen ; moroliko large 
pear-shaped gourds than pears ; they were received from 
Guernsey. Tho GatiUac, which is a stewing pear, has 
also appeared during the week, but, fine as they looked, 
there are some others which wo would very much ju'efcr 
to it for that purpose. The great objection to the Catillac 
