i 
250 PHENOMENA OF WINTER. 
that a workman of uncultivated mind cannot be far in advance of the mere' 
mechanism of his art ; but the genuine amateur, whose intellect soars far higher, 
and searches into causes, has attained already ample reason to discover that there] 
are, in every ray of light, agencies which are susceptible of numerous modifications.} 
Even the small projections upon a pane of common crown glass have long been 
known to exert a lenticular action resembling that of a burning-glass ; and more 
recent discoveries have shown that colouring materials, incorporated with glass, 
produce definite and sensible effects upon foliage and flowers. 
With these simple facts before us, pending inquiries of far higher moment, we 
have cause sufficient to pay the utmost attention to the effects of various kinds of 
glass when employed in diflbrent aspects. « | 
During the course of the present year, and a month or more of its predecessor; 
(1844), the condition of natural light has been most peculiar. The gardener was 
perplexed by the long and continuous gloom which commenced at the latter end^ 
of the autumn of that year. December was little better than a blank ; clouds 
entirely obscured the sun, and thus permitted little else than the weakest diffusion' 
of light ; and hence the radiation of heat from surfaces artificially heated, either- 
by fire or hot water, produced extension of parts, but no healthy organic action .| 
With this gloom there existed frost and wind of most penetrating character. f 
January became warmer, and more sunny. Contrary to its usual and proper 
character, it proved the only mild month of the winter, and four of its weeksj 
were isolated among [fifteen others of unwonted severity. This mild interlude, 
did much injury to a few of the most beautiful subjects of our winter gardens, 
because it induced some activity in the fluids, which subsequently became at once 
arrested by the extreme frost of February : thus Laurustinus, Sweet Bay, and 
above all, the Arbutus, were cut up, and in many places entirely destroyed. ! 
February was comparatively dry as to rain. Some snows fell, but the ground 
lacked that store of moisture which is seasonable, and then generally expected.j 
On the contrary, the first fortnight was bright and frosty, the intensity falling onj 
the 12th, when at sunrise, the night thermometer marked 27 degrees (i. e. 5 of 
Fahr.,) and in some gardens the mercury fell to zero. The average of the whole 
month was below freezing, and when March came in there was no prospect of a 
change. Thus it may safely be registered, that from the end of November to the 
10th of April, with the exception of the four mild weeks of January, the forcing' 
gardener had to struggle against absolute frost ; while, in the open air, the surface 
of water was never free from ice, and icicles hung suspended from the fronts of all 
the sashes. ' 
It is highly probable that a season of so much asperity will not speedily recur;; 
but it is always desirable to be provided with resources against such a calamity. 
One of these we fortunately possess in the strong and thick “ sheet glass ” of| 
modern introduction ; a medium that not only defends by its substance, but in a 
great degree prevents the escape of warm air from beneath, by the truth of its 
