241 
THE COTTAGE GARDENER AND COUNTRY 
black. This wire screen, standing as it does in the continued 
inclination of the roof, of course presents a metallic surface 
of black wire, and, say in summer time from 10 a.m. till 
3 p.m., receives the rays of the sun; the wire is then 
heated say from 80° to 100°, and consequently heats the air 
which passes through the interstices of wire, and I always 
find the thermometer placed under the shade of the Melon 
leaves standing at 80° or 85°; if a very hot day at 90°. The 
upper ends of the glass frame which forms the north side 
are raised by wedges according to the weather, from an inch 
I t) two inches high,' as soon as the sun is on the glass, and 
| mt closed till evening. This increases the indraught of air 
I through the wire screen, and I consider on every sunny day 
tin Melons are exposed from 11 a.m. till past 3 p.m. to as 
| hot an atmosphere as is experienced in the southern parts 
j of Italy, with almost as much ventilation as if growing quite 
in tie open air. 
I lave grown Persian Melons this way for some years 
I past, md obtained my bottom heat by tan and dry leaves, 
I lining the north or upper end of the bed with mowings of 
my grass, weeds, &c. of the summer. But the bottom-heat 
| was often too great in the early part of the season, and 
j declined too low in the latter part of the summer. Last 
spring, therefore, I adopted a certain mode of giving bottom- 
heat, which I contrived forty-one years ago, when I made 
my Grape-house, which is that of a steam-vault under the 
soil in which the plants are intended to grow. The steam- 
vault is formed by a brick arch ; the sketch supposes an end 
section before the end is closed up by the brickwork of the 
frame, a, a, brick nine-inch wall; b, b , the base of the 
elliptic arch to hold steam ; c, the steam-pipe which conveys 
the steam from the boiler, d, holding live gallons, to blow 
against the surface of the flat brick floor, and thus spread 
the steam all over the vault instead of rising to the top of 
the vault in the first instance; e, the feed cistern, with ball- 
cock on a level with the boiler to supply it with water; /, 
a small reservoir which holds eight gallons, to supply the 
feed cistern. 
I find boiling the water for about two hours at intervals 
of twenty-four hours, gives a certain heat to the soil above 
the arch, and that the temperature of this soil always 
corresponds with the quantity of water evaporated, as is 
shown by the sinking of the water in the upper cistern. 
According to Watt, steam at the temperature of 212° 
occupies 1500 times as much space as wdien it existed in its 
liquid state. I found that boiling the water for about two 
hours in twenty-four gave me, in ordinary weather in 
summer, a ground heat of from 78° to 82° or 83°, and that 
seven gallons of water were evaporated, as was shown 
by the loss of water from the upper cistern. Since 
1500x7 = 10,500, this number of gallons of steam must pass 
into the vault, and become condensed on the under surface 
of the arch and the upper surface of the brick floor, where 
it sinks into the ground and tends to keep up the heat. 
The Melon plants grew rapidly at about 82° of bottom- 
heat; but in the warm weather in June, finding it rising too 
high, T omitted boiling the water from Saturday evening till 
Monday evening ; this gave me a variable heat between 78° 
and 82°, the non-supply of heat for twenty-four hours on 
the Sunday giving the internal heat of the vault time to 
become reduced. My apparatus was rather too late in 
setting to work, and this, added to the unfavourable weather 
after the month of June, prevented my Melons ripening 
properly. I had, however, one or two of the Cabul Melons 
after being kept in a warm room for eight or ten days after 
they were gathered, which were melting and good ; and had 
the season been such as the summer of 1844, I have no 
doubt but they would have proved excellent .—(Horticultural 
Society's Journal.') 
GENTLEMAN’S COMPANION, January 0, 1857. 
GLASS FOR GARDEN STRUCTURES. 
As much discussion has of late arisen on the merits 
and demerits of the different kinds of glass used in 
garden structures, I have for once departed from the 
usual routine of kitchen-garden work to make a few 
remarks on this important subject, on which so much 
difference of opinion exists; and, in doing so, I will go 
back to a period when garden “ hothouses,” so called, 
were not so plentiful as now. At the same time, I will 
confine my observations to what has occurred under my 
own eye, except in the few cases which I will explain; 
and as the different descriptions of glass now in use 
afford good opportunities for comparing their respective 
merits, as well as calling back to memory those which 
preceded them, I will, for the sake of perspicuity, begin 
with the last-named first. 
One of the oldest glass-roofed houses that I remember 
ever seeing was a Vinery on the lean-to principle, 
differing but little in general features from those in 
use now, except that the frames of the sashes would 
be thought clumsy and unwieldy. They were made 
of oak, I believe, and had been in working order : 
about 115 years, dating from 1710, and, to all ap¬ 
pearances, seemed likely to last fifty years longer, as ( 
far as decay of most of the timber was concerned, ! 
although, at the time I saw it, there were but very 
slight vestiges of paint upon it. The glass, however, i 
was not such a durable material, and it is likely every ! 
part of it had been several times renewed, and iu 1826 i 
showed a heterogeneous mixture of the kinds common ! 
at that time, crown and under-duty glass being pre¬ 
eminent. I believe there are many older plant-houses, 
but the above is the oldest one with a glass roof that I 
have seen, and was then doing duty, and possibly is yet 
doing so. This, however, has little reference to the 
glass; but about that time, or when the late talented 
Mr. Loudon started The Gardeners' Magazine (the 
parent of all our gardening periodicals), a new move in 
the art of hothouse building took place, and curvilinear I 
iron-rooled hothouses were the order of the day, the ; 
glazing in some of them being done in squares not : 
much larger than a card. The quality of the glass was 
not much looked into, the flattest crown glass being, ! 
however, preferred; and the deep green kind with an 
uneven surface, which was said to be below the standard j 
of paying excise duty, was only used for repairing j 
frames, or by those whose means left them no choice. I 
But at that time the immense number of overlaps i 
in a house, and, consequently, openings for the ingress j 
of air, neutralised any little defect there might be in the j 
quality of the glass, while iu those older wooden houses I 
where larger squares were used the openings in the 1 
overlaps, from the unevenness of the glass, afforded, 
in like manner, an easy channel for the admission or j 
expulsion of air. This, with the heavy woodwork, dirt j 
in the overlaps, and other modes of shading, rendered 
the quality of the glass used a matter of less importance 
than now, when every crevice except the so-called legiti¬ 
mate “air-giving openings” is carefully closed up in the 
glass structure. 
But few changes took place in regard to glass from 
1820 until 1835, and the rage for curvilinear lean-to 
houses without rafters died away. Soon after the latter 
period it was found that the annual expense for 
painting was a serious affair, and other complaints were 
urged against them. But I may here remark, that 
though I by no means recommend iron houses of 
that class, I have found them to answer very well. 
However, about twenty years ago, or it may be more, 
sheet glass was introduced, and its applicability to be 
used in long squares soon brought it into general 
favour, and since 1840 it has been much employed. 
The great boon of removing the vexatious excise 
