RETROSPECT OF THE LATE WINTER. 
83 
by a vaporous atmosphere, even while in the external air the thermometer showed 
25° of frost, no mischief was occasioned. 
Having seen that one of the most cold and sombre winters upon record 
has been passed in security, we begin to think of shade as well as of light. A 
south sun is doubtless of great utility to plants under certain circumstances ; it 
stimulates vegetation, attracts the ascending fluids, promotes laboration and 
secretion ; but on the other hand the direct ray frequently burns, etiolates the 
petals of flowers, and scalds fruit. We require therefore a certain semitransparent 
medium, which shall produce a twofold effect ; first, that of a softened diffusion of 
the direct ray ; and second, that of protection from the cold of frosty nights. 
Close, but clear cloth, whether of linen or cotton, strained tight upon accurately 
made deal frames would answer the purpose well. These should be made to slide 
over the common glazed sashes, and be guarded from the force of wind by strips of 
wood fastened to the midribs of the rafters, also by a pin or two to fix the frame 
at top and bottom. Two advantages would attend the use of the screens, which 
cannot be obtained by a covering of mats on rollers : — security of position, avoiding 
those troublesome and injurious nailings and fixings, which so perplex the gardener 
in windy weather ; and above all, the increased temperature of the house, occa- 
sioned by the intervention of a stratum of air between the glass and the fabric of 
the screen, which would tend much to prevent that radiation which rapidly cools a 
house. Trouble and expense attend all the labours of man ; but when we reflect 
upon the great decrease of cost in glass, the super-excellence and strength of the 
new sheet glass, and the security from breakage conferred by sliding screens, 
persons who can afford good erections should not hesitate at a trifle to obtain 
immense advantages. 
We next require a good varnish for the fabric, one which will rather aid its 
transparency without rendering it liable to crack. If some preparation of Indian 
rubber could be employed, it might effect every object ; if not, common soft oil 
(not linseed) would preserve the fabric for a year ; and calico will soon be so cheap, 
that a renewal will be a mere trifle. The addition of a small quantity of white 
bleached wax to the droppings of olive oil, laid on while warm with a soft flat 
brush, would give texture to the coverino-. 
Having seen the destruction of numbers of beautifully made screens, which 
when new gave every promise to supersede glass, we must come back to glazed 
sashes, and fortunately the price is reduced just at the time when the quality is of 
first-rate excellence. A year or tw T o since we had only the quarrees of wretched 
crown glass, which snapped by dozens under the influence of a night's frost ; now, 
with large pieces six inches by nine, it is a rare circumstance to see a broken pane, 
and so true are the edges that a sash may be glazed without a single lap. The 
accuracy of the fittings, and the solidity of the glass, will secure at least 3° of 
temperature in excess ; and when, in addition, we cover with a calico-prepared 
screen, so fitted as not to be disturbed by any force of wind, a forcing-house may 
