May 15. 
COUNTRY GENTLEMAN’S COMPANION. 
115 
THE SWALLOW PIGEON. 
In The Cottage Gardener’s description of the New¬ 
castle Poultry Show, I see it stated that the pair of Swallow 
Pigeons there shown were the first that have been ex¬ 
hibited at any of our shows, which statement I beg to say 
is incorrect, as a pair were shown at Farningham in 1855; 
five pairs at the Surrey Zoological Show of December, 1853 ; 
and two pairs at the Great Metropolitan Show of 1854. 
The name “ Swallow ” is derived from the German 
“ Scbwalben.” They are so called from their marking re¬ 
sembling that of the Tern, or Small Elver Gull, which the 
Germans call a Sea Swallow.—>B. P. Brent, Bessell's Green , 
near Sevenoaks. 
NOTES AND QUERIES. 
I made an enquiry, some time ago, through your pages, 
if any of your readers knew any remedy for frosted Potatoes. 
I was reading an amusing book, written by Dr. Doran, a 
day or two ago, in which he remarks, that if Potatoes have 
been frosted, and they are kept in a dark place covered up, 
that they will recover from the frosting; lose the sweet 
flavour, and regain their mealy condition. Can any of your 
readers corroborate this ? Mine were in a well-lighted stable. 
Wooden ratlings and palings are greatly used by suburban 
gardeners, but soon rot at the bottom by resting on or in 
the ground. This may be avoided by leaving a space of one 
or two feet, and placing a row of slates on edge; they look 
neat, and, when painted the same colour as the palings, are 
hardly distinguishable. They, moreover, do not afford so 
snug a nest for slugs, mice, &c., and will resist rabbits. 
Has not Mr. Beaton made an error in the date of his 
foretold six weeks drought ? We have now been without rain 
at least a month, up to the second of May. Is all May to be 
as dry? 
Has any one heard the Cuckoo yet, and on what day ? For 
several years the first has always been on or near the 14th 
of April, as yet I have not heard one, 2nd of May. 
If the sun shines through the fruit trees at noon on 
Christmas day, it foretells a good fruit season; so says an 
old blue-apron, whose bloom-crowded trees I was admiring 
to-day.—W. X. W. 
THE WEST LONDON GARDENERS’ ASSOCIA¬ 
TION FOR MUTUAL INSTRUCTION. 
Mr. Cates’s paper on The Atmosphere of Hothouses 
was read. 
He considers that the atmosphere of hothouses demands 
the greatest attention, for upon the hvgrometric state of the 
air may be said to depend the health of plants, and also, to 
a certain extent, the perfection of the fruits raised in 
such structures. 
The causes that constantly operate in rendering the 
artificial climate of hothouses unnaturally dry, are con¬ 
densation of moisture on the glass, and damp, heated air 
constantly escaping through the laps of the glass, and by 
the doots and crevices of the building; this loss being 
constantly supplied by external air finding its way into the 
houses. 
It was also stated, that the quantity of water a cube of air 
will hold in invisible solution depends upon its temperature, 
and in proportion to the increase of temperature is the 
amount of moisture; and that every cube of air that enters 
the house at the temperature of 44°, and escapes at G0°, 
carries off with it twice the amount of moisture that it brought 
into the house at 44 u . Under such a system, long continued, 
the air would soon become too dry to support a healthy 
vegetation, and the soil, or any decomposing or fermenting 
matters, &c., that may be in the house, will be drained of a 
great proportion of their moisture, and so, to a certain extent, 
will the plants situated in such structures; therefore, arti¬ 
ficial means to counteract such excessive evaporation should 
be resorted to. It will also be found, that air entering at 
44°, and escaping at 80°, will carry off three times as much 
moisture as it brought in, and escaping at 100°, four times 
the quantity will be substracted, and so on, in proportion as 
the temperature is raised; this, if only continued for a few 
hours in the course of the day, would be found to be most 
destructive to plants of tender habit. 
Therefore, it requires no ordinary share of attention in 
ventilating forcing-houses in the early part of the season, 
and every precaution should be taken to prevent the air 
from entering in strong currents, so as to lower the pre¬ 
existing temperature gradually, and at the same time, as far 
as practicable, to avoid too great an escape of heated air. 
To prevent the internal atmosphere becoming too dry 
through the admission of external cold air, it will be 
necessary to prevent the plants suffering from an undue 
evaporation, frequently to syringe the walls and floor of 
the house, which on closing the lights will raise a kindly, 
moist, growing vapour. 
Experiments have proved that each square foot of glass 
contained in the roof of a hothouse will cool down li 
cube of heated air as many degrees per minute as the tem¬ 
perature of the internal exceeds that of the external air. 
So suppose the external air to be 40°, and that of the house 
60°, then, for every square foot of glass contained in the 
building, If cube of heated air will be cooled down 20° 
per minute, consequently, the moisture this air held in 
solution, in virtue of its 20° of heat, will be condensed by and 
deposited on the glass, and will escape by the laps of glass 
out of the house, or fall in drips, and it will also be found, 
that the greater the difference existing between the external 
and internal temperatures, the greater will be the amount of 
condensation. 
At high temperatures the expenditure of moisture is 
enormous, far greater than at low temperatures, and 
consequently more likely to prove injurious to the tender 
foliage of forced plants, or fruits, at an early season. 
As an illustration of the principle, he stated, that if we 
take the roof of a Pine-stove that contains 750 superficial 
feet of glass, and calculate that every square foot of glass 
will cool If- cube of heated air 30° per minute, with the 
internal temperature at 05°, then we shall find that 037 cube 
of air will be cooled 30° per minute; air saturated at the 
temperature of 05° contains about 6 50 grains of water per 
foot cube, and at the temperature of 30° it is saturated by 
2.25 grains, which gives 4.34 grains of water per cube lost 
in condensation on the glass per minute; consequently, if 
the atmosphere in such a house could be kept constantly 
saturated, there would he substracted about \ of a pint of 
water per minute, or about 12 quarts per hour, or at the rate 
| of 72 gallons in 24 hours; this enormous and unnecessary 
| expenditure of moisture must be obvious. 
The readiest mean^ to adopt to counteract such effects 
! would be to occasionally syringe the walls and paths, and 
1 the hot-water pipes or flues, and all available surfaces, and 
as the greatest amount of condensation or loss of water 
occurs at the highest temperatures, he considered the most 
effectual means to raise a constant supply of moisture woirld 
be to place evaporating- pans immediately in connection 
with the hot-water pipes or flues, as, by that means, the 
greatest amount of evaporation would occur simultaneously 
with the greatest amount of artificial heat, and also when 
the drain upon the artificial atmosphere was the greatest. 
He also considered that it was not prudent to admit one 
portion of air to enter the house merely to rob the other 
portion of its moisture; and yet this interchange is, to a 
certain extent, constantly occurring in badly glazed and 
badly constructed houses; hence the advantages of well 
glazed and air-tight houses to retain a humid atmosphere at 
the least possible amount of artificial heat. 
In conclusion, he alluded to the repose that plants require 
dining the night, as it is then, during their temporary 
cessation, caused by the absence of light, and a low tempera¬ 
ture, that they are enabled to recover their elasticity and 
vigour, and to replace the loss of water and other gaseous 
matter necessary to their health, and which were given off 
by evaporation the preceding day. He would, therefore, say 
that the colder the external air in the night time, the lower 
the artificial temperature in the house should range, com¬ 
patible with the safety of the plants or fruit-trees, the 
temperature to be gradually advanced to mid-day, and then 
to decline as gradually to the evening. This, he contended, 
