TEMPERATURE 17 
absolutely necessary, and work it at low pressure, than to 
have barely sufficient power and work it hard during severe 
weather, as the heat diffused in the latter case is harmful, 
Before deciding on the means of heating to be employed, 
it would be well to pay a visit to some of the collections 
noted for the excellent condition of their plants, and inspect 
the appliances and their arrangement. Most Orchid growers, 
whether in private establishments or nurseries, are willing to 
assist amateurs in these matters. When the apparatus has 
been got into working order, tests should be made to 
ensure an equal distribution of the heat from the piping. 
If a draught of hot air to any part of the house from be- 
neath the staging is observed, it is a good plan to build 
up openly-laid screens or brick walls 44 inches thick, the 
layers of brick being placed so that there is half the length 
of the brick opening between each brick and the next to it. 
Where there is a sufficient command of heat, these openly- 
laid brick walls, without mortar, built up below the side 
staging and running parallel with the edge of it, if they are 
syringed frequently, assist materially in preserving a healthy 
moisture in the house. 
TEMPERATURE 
One of the most important matters in Orchid cultivation 
is to see that a lower temperature is maintained at night 
than in the day. Nothing is more injurious to the plants 
than to be kept in a high temperature at night, nor is 
anything more contrary to natural conditions. All who have 
travelled in the countries from whence Orchids have been 
imported testify to the great difference between the tempera- 
B 
