1371.] 
IMPERISHABLE HOTHOUSES. 
211 
to E. Tryon, Esq. ; this had the base of the leaf to the extent of fully one-half 
of a rich glowing crimson, while the other half was of a bright golden yellow. 
Begonia multi flora elegans (f.o.c.), said to be perpetual-flowering, and bearing red 
blossoms, was shown by Messrs. E. G. Henderson and Sons, and will be very 
useful for house decoration. Variegated Zonal Pelargonium , Prospero , from Messrs. 
Carter and Co., had large and finely-coloured leaves, and a good habit, but it 
only received that very questionable compliment—a Second-Class Certificate. 
Juniperus chinensis aurea (f.c.c.), is a very handsome and valuable golden sport 
from the old Chinese Juniper, and as for the past sixteen years it has never 
once reverted to the green form, its character may Toe considered to be 
permanently fixed. It was exhibited by Mr. M. Young, of the Milford Nursery, 
near Godaiming.—E. D. 
IMPERISHABLE HOTHOUSES. 
MPEEISHABLE Hothouses ! Those who have had experience in the rotting 
of timber, the rusting of iron, the decay of putty and paint, which go on 
< ^ > so rapidly in hothouses of ordinary construction, will surely be in raptures 
when they hear of hothouses which are to be imperishable. And yet the 
expression, adopted as the title of a new mode of construction patented by Mr. 
Ayres, is not altogether a fancy, since the houses are built without either wood 
or putty, and are made up by a mere multiplication of similar parts, such as 
may be fitted together with facility by any intelligent workman. Besides this 
quality of durabilitjq it is claimed for them that they possess superior warmth, 
lightness, and portability, and that a reduction of material in construction and of 
the subsequent labour of painting is at the same time secured. 
The framework of the houses is constructed of cast and wrought iron in com¬ 
bination, the side walls of slabs made of terra-cotta or cement. The framework, 
combining the necessary maximum of strength with the minimum of material, gives 
but a trifling amount of shade. Thus the houses form almost a continuous sheet of 
glass, supported by strong light rafters of T-iron, G ft. apart, and with purlins to 
receive the ends of the squares of glass, 30 to 40 in. from each other. In 
this dull climate it is essential that in constructing plant-houses the light 
admitted should be as little intercepted as possible, for though for a few months 
in the height of the growing season we have more light than we may consider 
beneficial, and hence use shading, yet for the remaining portion light is frequently 
painfully deficient, and the plants suffer accordingly. 
Not only is light gained by this system of building, but warmth also. The 
great fault of ordinary iron houses is their cooling properties, arising from the 
fact that metal is a rapid conductor of heat. Now glass is an insulator of heat, 
and taking advantage of this property, the patent hothouses have been made, as 
far as possible, externally a continuous sheet of glass, both to protect the more 
perishable metal, and also to act as an insulator of the internal and external 
