208 SUGGESTIONS FOR THE MANAGEMENT OF PLANTS AND PLANT-HOUSES 
can be admitted at any and every part of tlie house, hut in severe weather it 
necessary to exercise great caution. Of all the plans which have come under o 
observation for winter ventilation, that of admitting cold air by means of drai 
passing from the outside of the back wall under the house to the heating apparati 
and escaping upwards among the hot-water pipes, is the best ; and if some wi 
gauze or perforated zinc be placed along every alternate light at the top of the hous 
the ventilation can be regulated with very great nicety, and without any fear of doii 
injury, so long as the heating apparatus is kept warm. The cold-air drains under tl 
house should be of considerable size, not less than nine inches square, so that, in tl 
case of ripening forced fruits, a large volume of fresh air can be constantly rushir 
in ; and as the quantity of air admitted will be governed by the escape at the top < 
the house, no fear need be entertained of cold currents, so long as the back vent 
lators are properly regulated. Of houses thus arranged we have never closed m 
cold-air drains at any time during the last three years, and by strangers the atmi 
sphere has always been admired for its fresh and wholesome feel. In these house 
the lower pipe of the heating apparatus is laid in a tank, so that the air receives 
necessary supply of moisture before it passes among the plants ; and when we requii 
a very moist atmosphere, it also passes through a coarse, moist, woollen net, whic 
makes it all that can be desired for plant cultivation. Of course, this system c|| 
ventilation enjoins a waste of heat and an increased consumption of fuel ; but that w 
do not care for, so long as we are sure we are benefiting our plants by the additional 
expense. 
Some modification of this plan we should recommend to every one who i 
desirous of excelling as a plant cultivator, and we would particularly impress upoi 
amateurs the importance of guarding against currents in their plant-houses, especial! 
during the winter season. Taking the precautions previously pointed out, anc 
guarding against over-excitement as to temperature, with due attention to watering 
and allowing each plant plenty of room, and thorough cleanliness both in the plants 
pots, stages, and houses, success is certain ; but neglect any one of these points, anc 
you will most assuredly and deservedly pay the penalty of your indiscretion beforci 
another summer dawns upon us. Next month we shall have something to say on 
the classification of plants in greenhouses, &c. 
