382 THE COTTAGE GARDENER AND COUNTRY GENTLEMAN, September 14, 1858. 
Their growth was immediately stopped, and the points of the 
shoots are dead. They also permanently injured a promising 
bed of Zinnias, Dahlias, and varieties of scarlet Salvias, 
Cammertonii in particular. Kidney Beans and Parsnips have 
been also materially injured. Onions not touched this time. 
I enclose a sample or two for your inspection. 
“ My object in troubling you with the above remarks, is 
chiefly in the hope that some of your entomological readers 
| will favour us with some particulars as to the species, the 
cause of its appearance, &c. 
“ The field Bean is partially injured by blight round 
this neighbourhood, but it appears to me to be a different 
species from the above, and the attack is not general.”— 
The Doctor’s Boy. 
[The particular species of aphis, alluded to in your letter, 
swarms, in a greater or less degree, every year, but only 
during the long - continued hottest and sultriest weather, 
especially if the atmosphere be in an excited electrical state. 
They then are known under the name of the Smother Fly, 
and in cholera years are supposed, by ignorant persons, to 
be the cause of that malady. The long-continued hot weather 
this summer has allowed them to propagate to an unusual 
extent.] 
ERECTING AN ORNAMENTAL GREENHOUSE. 
“ Will you give me a little advice respecting a greenhouse 
I want to erect. My garden is walled round, and the only 
place where I can conveniently erect my house will be at the top 
of the garden, against or upon a wall facing almost due east. 
This wall is seven feet six inches high. My house I propose 
to be eighteen feet long, and twelve feet wide, from back to 
front. The purpose I want it for will be solely for plants, 
Geraniums, &c. s with means of-heating sufficient to keep out 
frost, but not to force. Now, will you tell me what kind of 
roof I should have ? I fancy a span-roof, with the back span 
springing from the top of the wall: but should the span be 
equal both back and front ? and what height should the front 
be ? I mean the door to be in the front. The back wall I 
thought of covering with trellis arches, for creepers. I think 
of glazing the roof with Hartley’s rough glass : how should I 
ventilate it ? I think of having the front sashes all open, the 
same as in your £5 greenhouse, and yet I must have venti¬ 
lation at the back somewhere, and I cannot lower the back 
wall.”— L. R. Lucas. 
[In such a nice position for a greenhouse, with a flower 
garden in front, the first consideration with us would be 
a showy front, especially as the entrance is to be there. 
We would have the front, then, of much the same height as 
the present back wall, and from four to five feet of that we 
would have of glass, in moveable sashes. With a wall-plate 
at back, and one of equal height in front, one of the simplest 
modes would be to have a span-roof, equal on both sides, 
meeting in the centre, at ten or eleven feet from the floor, not 
in a single, but in a double ridge, with about nine inches 
between them. This space to befitted withventilating-boards, 
and covered outside with a wide ridge cowl, with openings 
all the way beneath, to admit air, and the cowl to keep out 
wet, as mentioned some time ago as in practice at Kimpton 
IIoo. Under such an arrangement, the walk would be in the 
centre. This would be the chief objection, as people in general 
like to walk round a house. Under this arrangement, with 
the exception of the ends and middle, rafters would not be 
required; strong sash-bars would do, fitted so as to receive 
glass, fifteen inches wide, and twelve inches deep. That may 
be of Hartley’s patent. The front should be of crown, or 
sheet, so as to be seen through. Instead of this, a short, sharp 
hip at back, of three feet, might be used to a ridge, and the 
front all in one piece; the hip, or part of it, being made to 
open. Or three feet, or two feet and a half of upright glass 
may be fixed on the top of the wall, between the wall and a 
stout wall-plate. The most of this two feet and a half of 
glass being made to open, by swinging on pivots near the 
centre, or otherwise. The main roof would then be in one 
S [°P®> ? nd fixcd . as befor0, % this means there might be a 
s licit of fifteen inchess all round, or more at front and less at 
back, a walk of two feet nine inches, and a bed or stage of 
lour feet in the centre. This, perhaps, would be the most 
attractive mode, as, if you gave top air at the centre of the 
ridge, you would require to get easily at that part, and, there¬ 
fore, have your walk in the middle, or else have pulleys or 
chains, and either ventilators there, or sashes made to move, 
instead of a fixed roof,—the latter, in our opinion, being a 
great security against breakage, &c., as well as cheaper at first. 
With the exception of the round flower-bed, which should be 
removed, the flower garden will want little alteration, with 
the exception of lessening the round and length of the figure 
a little on the south side. A small circle might then be 
placed in room of the one removed, or, what would be better, 
a basket of flowers, a vase, or a dial or statue,—anything that 
would be an ornament, and leave a larger space than now 
between the side beds, as seen from the door of the greenhouse.] 
HOW TO RETAIN PROPER TEMPERATURE IN 
A CONSERVATORY. 
“ I am experimenting on heating a small conservatory, but 
am at a loss to test the power of my boiler, as it requires much 
less heat to raise the thermometer 20° when the external air 
is at 60° than when it is at 20°. Can you tell me to what 
degree I should be able to raise my temperature at night 
when the thermometer stands out of doors at 60°, to enable 
me to command a beat of 40° all the winter, when the ther¬ 
mometer externally may be 15° or 20° ?”—A. 
[In answer to your question, we should say from 90° to 
100°; but, if you are thoroughly anxious to know if you are 
safe, tell us the size of your house, the surface of glass, the 
surface of boiler, and the quantity and surface of piping ; and 
that may save you wasting fuel, at present for no purpose but 
damaging what plants may be in the conservatory.] 
INDIFFERENT GRAPES ON VIGOROUS VINES. 
“ Five years since, I put up a span-roofed greenhouse, 
about nineteen feet long by fifteen feet wide, and twelve feet 
high to the centre beam, every part of which consists of glass, 
except the back and side walls, which face the north and west. 
It is heated by hot-water pipes, on the most approved principle, 
and has been pronounced by all gardeners who have seen it 
a model house. It enjoys the earliest morning sun, and the 
afternoon sun in July leaves it about half-past four. The 
ventilation is effected by sashes, which face the east and south, 
open top and bottom, and by ventilators in the south roof, 
which open and shut by pulleys. At the time of erecting the 
house, I put in twelve Vines of the Hamburgh and Muscadine 
sorts, in an outside border to the east, each of which is trained 
to a single cane, and fastened to rods about fifteen inches 
apart, and ten inches from the glass. The border for the 
Vines was dug about three feet deep, and, after depositing 
faggots at the bottom, was filled witli a strong loam, mix p.fl 
with prepared manure from a fellmonger’s-yard, and every¬ 
thing was done under what was considered first-rate advice. 
For the first two years, the Vines made marvellous growth. 
They were then brought into the house, and the border has 
been raised year by year, by manure, until it is now four feet 
deep, and reaches the holes at which the Vines are introduced, 
so that no part of the canes are left exposed between the out¬ 
side and inside of the house. Under all these apparently 
favourable circumstances, I naturally expected good Grapes; 
but, although the crop lias been good (twelve or fourteen 
bunches on each cane), the Grapes have for three successive 
years had the mildew. It has appeared as surely as the leaves, 
and only by a free use of black sulphur have I saved any 
Grapes at all, and the greater part of the bunches, instead of 
being compact and healthy, are weak and straggling F ”— 
Excelsior. 
[That the Vines grow so strongly, shows that you have at 
least plenty of manure in your border. That that strength 
should be associated with a free production of fruit shows 
that your wood is moderately ripened, and that the adding of 
manure on the surface has prevented the roots getting 
altogether beyond the reach of the oxygenating influence of the 
air. The straggling and thin appearance of the bunches, from 
such seemingly good wood, may be partly owing to the wood 
