April 6, 1889. 
THE GARDENING WORLD. 
one close by in contact with the air only. But the 
physical properties of water explain this seeming 
incongruity. There is what is called the “elastic 
force or tension of aqueous vapour,” that is, water has 
a tendency to pass off into vapour at all known natural 
temperatures, at least, at a rate dependent upon the 
degree of temperature and the degree of humidity of 
the atmosphere, as well as the superincumbent pressure 
of the atmosphere itself upon water or ice. Before 
water can pass into vapour it must absorb a certain 
amount of heat, and in the case of the wet bulb 
thermometer this is extracted from the bulb of the 
instrument, and from the atmosphere immediately 
surrounding it; consequently the lower the temper¬ 
ature of the wet bulb thermometer compared with that 
of the dry one, it indicates the greater rapidity of 
evaporation which is a measure of the dryness of the 
atmosphere at any given temperature. 
Should both the dry and wet bulb thermometer 
indicate the same degree of temperature, it is a sure 
sign that the atmosphere is saturated with moisture, 
and totally incapable of retaining any more in the 
form of vapour ; consequently, if the temperature were 
allowed to fall but one degree, or part of one, there 
would be a deposition of moisture in the form of dew 
upon the thermometers. This is what is spoken of as 
the dew point, a very important fact to remember in 
plant cultivation. The higher the temperature of the 
atmosphere of a house the more moisture it will retain 
in solution, so that it takes much more moisture to 
saturate the atmosphere of a stove than that of a 
greenhouse. It would, therefore, be important to 
ascertain the percentage of moisture in the atmosphere 
of different plant houses under one’s care, relative to 
the maximum necessary to saturate it at any given 
temperature. This can be readily ascertained by means 
of a set of hygrometrical tables adapted to the use of 
the dry and wet bulb thermometer, prepared by James 
Glaisher, F.R.S. No calculations are required of the 
plant grower, as these have already been worked out on 
mathematical or scientific principles, and given in the 
form of tables ranging from 10° to 100 Q Fah. 
Stoves. 
Under this heading may be included all such houses as 
are kept at a high temperature, ranging from 60° at 
night in winter to 75° or 80° in summer ; this would 
include plant stoves proper, warm conservatories, East- 
Indian Orchid houses, tropical ferneries, Pine-Apple, 
Melon, Cucumber and propagating pits. The atmo¬ 
sphere of these houses is more generally saturated with 
moisture than those kept at a lower temperature. For 
human beings the atmosphere is most agreeable and 
conducive to health when it contains from fifty to 
seventy per cent, of that amount of moisture necessary 
to saturate it; but it is often not only agreeable, but 
conducive to the well-being of plant life that the atmos¬ 
phere in which they are grown should contain a much 
greater percentage of moisture. This is particularly 
evident in the case of propagating pits, plant stoves, 
and tropical epiphytical Orchids, when the plants are 
making their growth. A saturated atmosphere is 
conducive to growth or the extension of tissue, by 
reducing the amount of transpiration and evaporation 
from the surface of the leaves and other exposed parts, 
thus allowing the tissues to become gorged with water 
and the cells to be in a state of tension. Without this 
no growth at all could take place. 
Excessive atmospheric humidity, however, must not be 
permitted for an unlimited space of time even in these 
warm houses, otherwise evil results will follow. 
Phalaenopsis, for instance, if constantly grown in an 
atmosphere like that described, will suffer considerable 
injury if afterwards removed to a house with a drier 
atmosphere. The same evil is noticeable in Caladiums 
at plant exhibitions, where the broad, limp, thin leaves 
become half shrivelled up before the day is halt over, 
provided they have been constantly grown in a warm, 
humid atmosphere for some time previous to their being 
exhibited. This is also seen in the case of all other 
stove plants, but particularly so in those having large 
leaves. Nowhere, perhaps, are the evil effects more 
noticeable than in the case of tropical Ferns, especially 
the finer-leaved kinds, such as the Adiantums. By the 
maintenance of a close humid atmosphere and the use 
of shading while making their growth in summer, we 
obtain an ample leafage ; but if this is closely examined 
it will be seen to be thin, membraneous and devoid of 
substance. Adiantums particularly are affected in this 
way, and before the winter is half through instead of 
exhibiting their wonted lively shades of green, they 
become brown, disfigured and quite worthless for 
decorative purposes. Instances might be multiplied, 
but this will serve to show a state of matters that 
should be avoided by all good cultivators. 
This state of matters is best remedied by less shading 
and more ventilation. The latter will modify not only 
the conditions of heat and moisture, but will bring 
more fresh air in contact with the leaves, and by the 
use of less shading we greatly increase the power of the 
plant to produce more solid material for the building 
up of its internal tissues and the thickening of the 
same, so that instead of broad flabby leaves they will 
be more leathery, and thickened to a degree which will 
enable them to endure for a much longer period of time 
even in dry atmospheres, such as that of a dwelling- 
house when required for decorative purposes. In the 
case of forcing houses the evil effects of bad ventilation 
are of common occurrence, when the cultivator is some¬ 
times least able to help himself owing to the severity of 
the weather, which necessitates keeping the ventilators 
closed. Stems and leaves become drawn, feeble, and 
devoid of stability. Seeing that the whole of the 
carbonaceous material utilised by the plant is directly 
derived from the atmosphere, a good supply of fresh air 
is indispensable to firm and stable growth. Plenty of 
suulightis also an absolute necessity to enable the plant 
to fix the carbon. Heat and moisture alone would be 
productive of growth similar to the work of a building 
contractor, who rapidly builds up a house that is a 
mere skeleton, of no stability. 
The psychrometer in these houses would prove a 
most useful instrument in the hands of observant 
cultivators, because by its use they could regulate the 
humidity of the atmosphere to that amount which is 
most conducive to the welfare of the different plants 
grown. Some, no doubt, to whom the idea is a novel 
one, will be inclined to pooh-pooh it as of no 
practical value or use ; but the same might be said of 
the thermometer itself, which many growers dispense 
with altogether. This, moreover, is not indicative of 
progress in gardening, and is altogether unworthy of 
the present age of advancement. Tli9 practical man 
has an excellent opportunity of adding to the store of 
useful knowledge concerning plant life, by being con¬ 
stantly amongst the plants themselves, whose require¬ 
ments and the means of supplying them should always 
be uppermost in his mind. The scientific man labours 
under a great disadvantage in this respect, in that the 
scene of his labours is generally at a distance from the 
P^ an * :s - ( To be continued.) 
-- 
THE FERNERY. 
Potting Hardy and Half-hardy Ferns. 
In the case of Ferns that are kept in warm houses, 
they must needs be potted before this time, as growth 
commences earlier. In the cool house, however, and 
especially if that is situated behind a north wall or 
where it is shaded from direct sunlight, few if any of 
the Ferns will have yet commenced to grow ; therefore 
the present will be a suitable time for re-potting the 
great bulk of them. A good general compost may 
consist of fibrous loam one part, good peat not bog-soil 
one part, and half a part consisting of broken pot¬ 
sherds and sand. Chopped sphagnum is also an 
excellent material for mixing with Fern compost, and 
may be employed with advantage if obtainable. 
Not only do the smaller British Ferns form choice and 
interesting subjects for pot culture, but many of the 
more ornamental crested kinds, such as the varieties of 
Aspidium angulare, the crested forms of the Lady Fern 
(Asplenium Filix-fcemina), and even those of the 
common male Fern, including Nephrodium Filix-mas 
cristata angustata, with its long, narrow, arching fronds. 
The fronds of the Lady Ferns die down early in autumn, 
but during their prime are almost indispensable in a 
roomy house on account of their feathery gracefulness 
and light green colour. All of these may be grown in 
pots proportionate to the size of the ball of roots. 
Some of them are well adapted for basket culture, such 
as the drooping forms of Aspidium angulare, that are 
strictly evergreen and extremely ornamental in a large 
state. When turning the plants out of the pots the 
crocks and a quantity of the old soil may be removed, if 
it is desirable to use the same size again. With a little 
care this can easily be effected with tho fingers or a 
blunt-pointed piece of wood, without injury to the Ferns 
themselves. Except in the case of rapidly increasing 
kinds, Ferns grown under cool treatment had best be 
kept in pots that are rather small than otherwise. The 
roots can then more easily take possession of the whole 
ball of soil and prevent it from getting sour, which is 
liable to be the case owing to the quantity of water 
required as a rule during the summer months. 
The Aspleniums and other rock-loving Ferns should 
have the addition of some porous pieces of sandstone, 
either red or white, mixed with the compost used for 
the general batch. Some growers might advise pieces 
of granite, but sandstone is more retentive of moisture, 
and therefore more encouraging to the roots. The 
common Maidenhair (Adiantum Capillus-Veneris) 
delights in some pieces of porous material worked in 
amongst the roots, and so does Asplenium germanicum, 
A. septentrionale, A. Ceterach, Woodsia ilvensis, 
W. hyperborea, and others. The Killarney Fern 
(Trichomanes radicans) and the other British filmy 
Ferns—namely, the two species of Hymenophyllum, 
may even be planted on a slab of some porous stone ; 
but to give satisfaction they should also be grown 
under a bell-glass to keep the fronds properly moist, 
without having to saturate the atmosphere to the 
disadvantage of other kinds, as well as to the dise 
comfort of people inspecting the Ferns. All thes- 
small species, with the exception of the filmy Ferns, 
should have their crowns distinctly above the sur¬ 
rounding soil (but not so as to expose the roots) to 
prevent them from being water-logged or otherwise 
injured by excessive damp during winter. 
Where space can be afforded a number of half-hardy 
exotic as well as British Ferns may be grown to 
perfection in the same house, and under the same 
treatment. Amongst the neater kinds we have Os- 
munda regalis palustris, Asplenium Ceterach aureum, 
Nephrodium erythrosora, Aspidium munitum, A. 
falcatum, A. f. Fortunei, Pelljei rotundifolia, and 
numerous other very pretty kinds. The last is very 
suitable for basketwork. 
->X<- 
OTES FROM SCOTLAND, 
Dogs v. Flowers. — In the Aberdeen Sheriff’s 
Court, on Thursday, the ‘28 th ult., before Sheriff 
Dove Wilson, William Bisset, gardener, Pitmuxton 
House, Aberdeenshire, sued William Slora, gardener, 
Bloomfield, for £12 in name of loss and damage sus¬ 
tained by him in consequence of the defender having 
destroyed two of his dogs by poisoning them. Some 
few weeks ago (to let readers understand the case 
aright) Slora was punished in the Aberdeen Criminal 
Court for poisoning the dogs. On Thursday he lodged 
a counter-claim for damages done by Bisset’s dogs, his 
bill being as follows :— 
120 Pansies (named), at 3s. per dozen 
120 ,, ,, ,, >, ••• 
50 ,, (unnamed), at 2s. ,, 
36 ,, ,, >, ,, • •• 
96 dozen Calceolarias, at Is. 6d. per 
dozen . . 
35 Stocks (All the Tear Round), at 6tf. 
each... ... ... ... ... 
1 bed of white Lilies ... 
53 square feet of glass, at Is. per square 
foot ... 
£1 
1 
0 
0 
10 
10 
8 
6 
4 0 
17 
5 
2 13 0 
£14 13 10 
Restricted to £12. 
The evidence led for Bisset’s action was on the same 
lines as that given at the trial of Slora for poisoning 
tho dogs, and was to the effect that because Bisset’s 
dogs had broken some of the glass of Slora’s green¬ 
houses, Slora threatened to poison the dogs. He had 
shown some of the witnesses a packet which he said 
contained strychnine, remarking that he would give the 
dogs a dose of something that would keep them at 
home. On the day after Slora made that threat, 
Bisset’s dogs were taken ill, one of them dying that 
day, and the other some days afterwards. Several 
pieces of meat containing strychnine were found on 
Slora’s ground. The ground, it was explained to the 
court, was not enclosed, so that any dog could wander 
on to it. For Slora’s defence, several witnesses were 
examined to prove that Bisset’s dogs had done a great 
amount of damage by breaking glass and destroying 
plants, and that Slora used poison for vermiD. The 
evidence as to the value of the dogs was very con¬ 
flicting, one witness declaring he would not take them 
as a present. Sheriff Wilson, in giving judgment, held 
it proved that Slora had poisoned the dogs, and 
remarked that people who poisoned dogs had to pay 
fancy prices for them, having to reckon with the injury 
to feelings which their actions caused. £3 would be a 
fair sum for each dog. As to the counter-claim by 
Slora, it was surely rather extravagant, for ninety-six 
dozen of Calceolarias represented a tremendous amount 
of scraping by two dogs. It was not likely, however, 
his lordship added, that Slora would be so wicked as to 
poison the dogs without some excuse, and he allowed 
him, in name of damages for plants destroyed, £1 j he, 
however, must pay the expenses. If he had any com¬ 
plaint against the dogs, he should have sued the owner 
for damages instead of poisoning them.—Co;-. 
