98 Remarks on JVuod and Metal Hot-House Roofs. 
prices, and some very pretty drawings of hot-houses recently built with 
patent sashes. 1 had to make 66 new sashes at that time, but I told 
the patentee that I could not think of giving £1 18s. 6d. at Birmingham, 
for that which I could have made for £1 3s, 6d. at home; even if the 
per centage fee was doubled ; and as to their everlasting durability, I 
conceived it was quite impossible that wood mortices and metal tenons 
could last twenty years — which was the case, those sashes which 1 went 
to see had to be changed in less time than those named by Mr. M'' Mur- 
trie, who may well advise gentlemen to pause and reflect before they 
erect such things in a Frvit-forcinc] garden. 
As to the more recent invention of hot-houses with rafters and sashes 
all of metal, whether copper, cast-iron, or cast-steel, the well known 
powers of all kinds of metal as conductors of heat and cold, and their 
susceptibihty of both, as regards their expandmg and contracting pow- 
ers, are so great, that if they do not cram the walls down by expansion, 
nor receive fractures by contraction, they certainly are improper mate- 
rials for exciting vegetation, particularly early in the season. 
The following practical case will bear upon the point in question: — 
I have seen a cast-iron pine-stove, with the metal so much contracted in 
the winter months, that the interstices were obliged to be stuffed with 
moss and wool, and even then the hoar-frost has appeared in some pla- 
ces in the inside of the roof, and the gardener assured me, that in hot 
weather the expansion was so great, that it was very difficult to move 
the sashes for ventilation, and the conducting powers of the metal ren- 
dered a continual watching necessary, to regulate the temperature. 
It is now frequent for retired tradesmen to have gardens, and to build 
small Hot-houses. I know an instance of one who wished to have a few 
grapes and keep a few plants for amusement ; he took bad advice and 
built one of those gay, expensive, kickshaw things, with an idea to 
eclipse a more frugal neighbour, who had a wood hot-house, but he 
soon found out that it was a mistake ; the money was gone, and the pro- 
duce never came, under the management of the gentleman and his raaii- 
of-all-works. I could give names, &c., but that would be adding insult 
to disappointment, — a caution to other gentlemen is here intended. In 
cases of this kind, the hot-house of some intelligent nurseryman often 
presents a tolerably good pattern ; there is generally economy and use- 
fulness combined. Sometimes cases occur where such erections can be 
attached to the library or drawing-room — a good plan and paper on this 
is given in the " Gardener's Magazine,'' vol. VI. page 664. 
When it is intended to build a hot-house, there generally is some 
particular specified purpose in view, such as grapes, peaches, pine- 
apples, or botanical plants, more or less hardy, &c. ; those consider-^ 
ations ought to rule not only the form and dimensions of the house, but 
the p'.tch of the roof, which is a n:ost essential point as rec:ards early or 
