18 THE PARLOR GARDENER. 



the plants must be the better for this. Do not 

 put your plants in a room in which the chimney 

 smokes ; or in a place warmed by a stove or fur- 

 nace ; they will have too little air in this latter 

 case. You will say, that, in the greenhouses and 

 conservatories it is by various systems of warming- 

 pipes that a proper temperature is kept up ; and 

 that the plants do well. This is true ; but along- 

 side of the heat pipes are pipes for ventilation, 

 bringing continually into the greenhouse the air 

 from without, which is warmed by its contact 

 with the heat pipes before it mixes with the in- 

 terior air ; and the freshness of this interior air is 

 thereby maintained. Not so in a chamber warmed 



by a stove. 



Cleaning. 



Plants in a room have really but one enemy 

 the dust necessarily raised by sweeping. Those 

 plants, as the camellias, kalmias, and rhododen- 

 drons, which have leaves both large and thick 

 enough for the process, ought to be wiped at least 

 twice a week with a moistened sponge. As to 

 those whose leaves are too small to admit of this 

 sort of cleaning, as the ericas (heaths) and the 



