JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
404 
[ November 2, 1882. 
ordinary type is blue, but there is a white-flowered form and one 
with variegated leaves. 
APHELEXIS. 
These require to be grown in a compost of fibry peat and sharp 
sand, with a little leaf soil ; or some prefer light turfy loam with 
sandy peat, and this is preferable if the drainage be good and a 
few pieces of charcoal be mixed with the soil. Great care is 
needed in watering these plants, as the slightest excess of moisture 
or a corresponding deficiency will produce most unsatisfactory 
results. After potting the plants should be kept in a rather higher 
temperature than usual for a short time until root-action has re¬ 
commenced, occasionally syringing them lightly, but giving little 
water until it is seen that some advance is being made. Shading 
will also be then necessary for a time, though afterwards the plants 
must have as light a position as possible. During the summer a 
cold frame will be a suitable place ; but in the winter, if there is 
no house specially devoted to hardwooded plants, the warmest 
position in the greenhouse should be assigned them. They are 
very useful, as the flowers last so long, and they are greatly valued 
for exhibition, as fine globular specimens can be readily obtained 
with ordinary care in the culture and training. The species and 
varieties in general cultivation are not very numerous, but the 
following four are the best known :—A. Barnesi, bright rose ; 
A. humilis grandiflora, purplish rose; A. macrantha purpurea, rich 
purple ; and A. macrantha rosea, of a pale but pleasing pink hue. 
AZALEA INDICA. 
This is a general favourite, and rightly so, for few hardwooded 
plants may compare with it. It is of easy culture, but neverthe¬ 
less not many amateurs succeed with it. The chief reasons are 
that the plants are generally starved and rootbound or potted 
in unsuitable soil, and the foliage is allowed to be overrun with 
thrips. The best compost for Azaleas is peat and sand—good 
fibry peat, with a sprinkling of sand to keep it open. Peat may 
have to be purchased, for any kind of peat will not do, and it is 
rarely that good peat is to be obtained otherwise, more especially 
by urban growers. 
The season for potting is just after flowering, or when new 
shoots start. Of course potting is not needed unless the pot they 
occupy is already full of roots or soured through over-watering. 
In the latter case it may be necessary to remove as much soil as 
possible without injuring the roots too much ; in the first case the 
removal of the crocks and any loose soil will be quite sufficient. 
Too large shifts should not be given, for the new soil may become 
sour before the roots take possession of it, in which case they 
never will succeed in it. From a 6-inch to an 8-inch and from 
an 8-inch to a 10-inch pot are quite sufficient. 
In potting Azaleas it must be carefully observed that the 
ball is not dry, or there will be no possibility of moistening 
it thoroughly afterwards without wetting the new soil far too 
much. It is therefore necessary to examine the plants twenty- 
four hours before potting takes place, and to steep them if dry for 
an hour or two, and then allow the ball to partially dry before 
potting. The new soil must be rammed quite as firm as the old 
ball. Hardwooded plants which have fine hair-like roots and are 
potted in peat are very liable to be injured, and in thousands of 
instances killed, through the neglect of the simple precautions I 
have endeavoured to explain. 
After potting the plants must be placed in the greenhouse again, 
or in a warm structure if such be at command, a night temperature 
of 50° being maintained. At sunset or before, light syringings of 
tepid water will be very beneficial. Indeed, amateurs should 
begin not later than the middle of February to keep up such a 
temperature just for the sake of forwarding the Azaleas as well as 
for enabling spring bulbs—Hyacinths, Tulips, &c.—Primulas, and 
other greenhouse plants, to assume their best character. It is quite 
necessary for the Azaleas, as in greenhouses where frost is excluded 
and no more, they make their growth so late in the season that 
they do not ripen nor the flower buds set, and the consequence is 
a poor display of blooms. Where Vines are being forced these 
plants will do well, but I do not advise placing them in vineries, 
for they are very apt to introduce thrips and other insects. 
By midsummer, after the buds can be felt between the finger 
and thumb, the plants may be placed out of doors with much bene¬ 
fit. The pots should be half plunged in ashes to prevent the sun 
scorching and unduly drying the roots. I recommend ashes 
because worms will not readily crawl through them into the pots. 
If worms enter pots the balls should be inverted into the hand 
and the worms removed. Lime water will dislodge them from 
ordinary plants, but lime water is injurious to hardwooded plants 
generally, and for none more so than Azaleas. Liquid manure 
may be occasionally given to root-bound plants. 
Thrips are the great pest of this plant. Syringing with soft- 
soap water will prevent its appearing, and hard syringings with 
water at a temperature of 140° and with a little softsoap in it 
will effectually wash them off if they appear. Tobacco water will 
also eradicate them. The thrips must be kept down, or healthy 
plants cannot be had. 
Bush form is the simplest and most natural form for them, and 
for one unaccustomed to the intricacies of training is the best that 
an amateur can adopt; but pyramids are the favourite shape into 
which they are trained. The way to form a pyramid is to insert 
a stout stake the desired height in the centre of the pot; two cross 
stakes are fastened across the mouth of the pot to this central 
stake and to a stout cord tied under the rim of the pot; then a 
ring of copper or galvanised wire is fastened to these cross stakes 
of the desired width, and small wires taken from the rim of the 
wire and fastened to the top of the centre stake. To these wires 
the growth is trained. 
The names of half a dozen kinds are appended, to which the 
cultivator may add after a little experience has been gained. The 
varieties are almost innumerable, but the following are good :— 
Duchesse Adelaide de Nassau, A. Borsig, Iveryana, Flag of Truce, 
Punctulata, and Heine des Pays Bas.—J. H. 
THE FORMATION OF DEW. 
I have read Mr. Taylor’s book on “Vines at Longleat” with 
great pleasure and profit. It carries to one’s mind the word 
“thorough” in a very remarkable way. No labour too great to 
achieve the end in view ; a genuine scientific spirit; patient keen 
observation ; seeking out of cause and applying remedy, lightened 
up not a little by touches of real humour. 
Before it passes to further editions there is one point which it 
might possibly be worth Mr. Taylor’s while, to use an awkward 
phrase, to reconsider—namely, what follows on page 60 the words 
“ The dew is caused in the following way.” Our friend is per¬ 
fectly right in his observations on page 61 that it is the “rapid 
evaporation which causes the complete chill,” by what is known as 
the immense quantity of “ latent ” heat taken up during evapora¬ 
tion ; but the cause of the original deposition of the dew is not, 
I think, precisely what he says. 
The whole theory of dew was first pointed out by a Dr. Wells 
in a most interesting pamphlet, published, I think, thirty or forty 
years ago, which I wish I had to send to Mr. Taylor, but I will try 
and explain very briefly what I can of it; and it may be shortly 
stated by the broad fact that hot air can hold more moisture, 
invisible, than cold air, and that as the cooling process goes on the 
air becomes saturated— i.e., can hold no more invisible moisture, 
but must deposit it or make it apparent in the form of fog, &c. If 
there is anything colder than the air itself, then dew is deposited 
on that substance. This is easily tried. Bring a tumbler of cold 
water, iced if possible, into a warm room ; the tumbler chills the 
air round it below the point called the “ dew point,” at which it is 
saturated, and the moisture is condensed on the glass. 
Now it seems to be a provision of Nature that plants have large 
powers of absorbing heat, and apparently a somewhat equivalent 
power of radiating—getting rid of it—also ; doubtless the last to 
attract dew to refresh and invigorate them, as Mr. Taylor points 
out, and which power seems to be, as he says, in proportion to the 
vigour of the plant. 
Well, to return to Mr. Taylor’s house, which, as he says, is getting 
cooled during the night—that is, the air is approaching more or 
less to the point of “ saturation.” It is not the rise of temperature 
caused by the sun coming out which causes the dew to deposit on 
the Vines, slates, &c,, because any rise of temperature must infal¬ 
libly cause an increase in the moisture-carrying capacity of the 
air before it can cause much moisture to be evaporated from the 
ground in the house, or anything in the house ; but it is the 
radiating power of the plants and other substances which have, so 
to speak, chilled themselves, and thus previously caused the air to 
deposit dew on them, just as on the artificially chilled tumbler. 
I think that just before sunrise a distinct and sudden drop in the 
temperature often takes place, and probably the dew may be 
largely deposited at this time, which may have led Mr. Taylor to 
speak of it as being caused by the sunrise. 
The point is so small it may not be worth while troubling Mr. 
Taylor at all about it, but theoretically the cause of dew-deposit is 
an interesting one to gardeners, and he would, I am sure, be in¬ 
terested in watching a dry and wet bulb thermometer, by which 
the dew point can be at any moment calculated, and the amount of 
moisture in the air approximately seen at all times.—W. Y. 
Notes on Pears Wanted. —Have any of your correspondents 
any personal knowledge of the following Pears ? Early and mid- 
