134 HOT-HOUSE. [January. 
two, or three inches, according to the weather, and let it 
always be done from eleven to one o'clock ; but by no means 
in such a manner as to cause a draft in the interior of 
the house, which would be very prejudicial. Therefore, be 
always cautious during cold weather in administering that 
necessary element to vegetation, which is so conducive to 
health. 
OF FIRING AND FUEL. 
The hot-house ought never to be left entirely to inexpe- 
rienced persons, because they are not aware what might be 
the result of inattention even for an hour. Attention 
to the following observations will obviate every difficulty : 
About this season of the year, frost generally sets in very 
severe in the Middle States. Suppose the day may have all 
the clemency of spring, the night may be directly the re- 
verse. Every precaution is necessary to guard against 
extremes. The shutters are put on every night at sun- 
down, and, in severe weather, as soon as the sun goes off 
the glass. If the shutters are omitted till late in severe 
frost, it will so reduce the heat of the house that you can- 
not overcome it by fire until near midnight ; and when 
done, the fire or fires have been made more powerful than 
they ought to be, proving ungenial to the plants that are 
near the flues. The air, as above directed, having been 
taken off the house at one o'clock, as soon as the mercury 
begins to fall in the thermometer, kindle the fire, and, sup- 
posing it is anthracite coal, in twenty minutes, with a good 
drawing furnace, the heat will operate in the house. If a 
coal fire, kindled about four o'clock, it will require an addi- 
tion about six, and then may be made up again about nine 
or ten, which will suffice until morning. The quantity 
must be regulated by the weather. If the fuel is wood, it 
must be attended to three or four times during the evening; 
and, when the mornings are intensely cold, a fire may be 
requisite. When there are bad-drawing furnaces, the fires 
must be made much earlier, perhaps by two or three o'clock, 
which will be easily observed by the time the fire takes 
effect upon the air of the house. The temperature ought 
never to be under fifty degrees of Fahrenheit. 
