THE NATURAL CONDITIONS OF PLANTS. 55 
full southern exposure. They generally flower 
four or five months in every year, the only 
attention which they require, being to prune 
them after each flowering. 
It would be waste of time to detail any more 
of these minor experiments, and I shall, there- 
fore, now describe the largest experimental house 
which I fitted up in Wellclose Square. The 
object which I had in view was to obtain as many 
varied modifications of the natural conditions of 
plants as it was possible to procure in the small 
space to which I was confined. 
The length was twenty- four feet, width twelve, 
and. extreme height eleven feet. Over the door 
was this line : — 
64 Exiguus spatio, variis sed fertilis herbis,” 
which may be thus translated — 
44 You scarce upon the borders enter, 
Before you ’re in the very centre ; 
Yet, in this narrow compass, we 
Observe a vast variety.” 
By building up rock -work to within a foot of 
the glass, and by varying the surface in every 
possible way, very different degrees of heat, light, 
and moisture, were obtained to suit the varying 
wants of the plants. The house was heated in 
winter by means of hot-water pipes which pre- 
served the lower portion during that season at 
