October 10, 1891. 
THE GARDENING WORLD 
85 
bottles; it being much wiser to use it twice in a 
weaker state. Clear soft water, of about 70°, is an 
excellent thing to syringe all Roses with upon bright 
mornings when in full growth, and if this is used 
frequently and judiciously very few insects will 
trouble the plants. 
Cold draughts and dryness at the roots when in 
full growth are the chief causes of mildew, and 
must be avoided. But whenever you notice this 
insiduous blight appearing use a little soft soap and 
sulphur (black is the best as being less unsightly). 
The best way is to mix the sulphur up into a paste 
before adding it to the soft soap water ; and if you 
keep the whole solution well stirred during use there 
will be a nice and gentle dusting of sulphur all over 
the foliage of your plants. This will check if it does 
not eradicate the fungus.— Experience. 
EFFECT OF THE ELEC¬ 
TRIC LIGHT ON PLANTS. 
The results of some experiments on the influence of 
the electric arc lamp on plants in hothouses is given 
by the authorities of the Cornell University Agricul¬ 
tural Experiment Station in Bulletin No. 30. The 
experiments were carried on during the winter of 
1889-90, by introducing an ordinary street lamp into 
a house set apart for the purpose. This house was 
60 ft. long and 20 ft. wide, and was divided into two 
equal portions by wooden partitions, so that one 
half might be kept dark during the night, while the 
other enjoyed sunlight during the day, and was 
kept lighted by the electric lamp at night. The 
electric lamp was suspended from the ridge of the 
house, just 2J ft. above the soil of one of four 
benches just below it. 
The brush arc lamp used was of 2,000 nominal 
candle power, and during the first six weeks com¬ 
mencing January 23rd, 1890, the light was naked, 
but during the rest of the time up to April 12th, it 
was covered by an ordinary white opal globe. While 
the light was kept naked it showed a marked influence 
in hastening the maturity of such leaf plants as 
Endive, Spinach, Cress, and Lettuce. This was the 
more marked the nearer they were to the light, and 
the leaves were small and more or less curled or injured 
close to it. Notwithstanding this, they contained 
the same amount of starch as leaves of plants at a 
greater distance from the light, but the grains were 
larger and better developed. The result was that 
the plants ran to seed without forming leaves large 
enough to be useful for table purposes. 
The other division of the house lighted by sun¬ 
shine only during the day was planted at the same 
time for comparison with that under the influence of 
the electric light. While Spinach and Lettuce 
in the latter house were making small leaves and 
throwing up flower stems, similar plants in the un¬ 
lighted house retained their dwarf spreading habit, 
and made good edible leaves. Within 3 ft. of the 
lamp on either side the plants were killed outright, 
while all the rest were seriously crippled in the 
lighted house. Cress behaved in the same way, 
and for 5 ft. on either side of the lamp, the plants 
died soon after germinating. In the case of Endive, 
some striking inferences could be made. Two rows 
grew side by side in the lighted house, and one of 
them was shaded by an iron post, 1J in. in diameter. 
The average weight of six plants in full light was 
36-16 grains, in the shade 93-83 grains, while the 
average weight in the house lighted by the sun only 
during the day was 575 grains, the leaves being 
larger and darker in colour. The plants shaded by 
the post were heaviest in the deepest shade close to 
the post and the lamp, while in full light the best 
plants were farthest from the lamp. 
The chemical analysis of Radishes grown under 
those three conditions showed that a greater amount 
of ash, including more than double the amount of 
potash and more chlorophyll, was developed in the 
plants under the direct influence of light, while the 
amount was least in the dark house. Plants in the 
shadow of the post were intermediate in these respects. 
The nitrogen was essentially the same in all cases. 
Dwarf Peas were grown upon a bench considerably 
lower than another one, which consequently shaded 
about half of it. The Peas flowered about a week in 
advance of those in the dark house, and the amount 
of bloom v\as ultimately the same in both houses, 
but the best crop was produced by the plants in the 
dark house, \yhej-e the pods filled much better 
Experiments were then made with Radishes, to 
test whether the injury was due to continuous light. 
Flower pots were inverted over some newly-planted 
seeds and removed during the night, so that the 
seedlings might be exposed to the electric light only. 
They grew rapidly at first, but never succeeded in 
producing anything but elongated stems and the 
cotyledonary leaves, and died in the course of three 
or four weeks. Strong Lettuce plants were sub¬ 
jected to the same treatment and died in about two 
weeks ; Beans died in less than six weeks from the 
setting of the seeds ; Maize died in less than five 
weeks; and the Castor-oil plant died- in two weeks, 
although established some time before it was covered 
over excluding sunlight. Similar experiments were 
carried on with the German Ivy (Senicio scandens), 
Carnations, Peas, and Begonias, but all died in a 
relatively short time. The above results with the 
naked arc light are conclusive that no beneficial 
results can be obtained from the electric light in 
that way. 
Another set of experiments was carried out on the 
same principles as the above except that a white 
opal globe was placed over the lamp. Here the in¬ 
fluences were less marked upon the plants. Radishes 
grew well, but did better in the dark house. Lettuce, 
on the contrary, did best in the light house. The 
loss caused by the electric light varied from one to 
five per cent, where the light was covered by an 
opal globe, but the naked light caused a loss of 
forty-five to si\'ty-five per cent. Curiously enough, 
Carrots were less affected either by the naked or 
protected light than any other crop, being only from 
one to thirteen per cent, better in the dark house. 
No other plant stood the light so well, as those close 
to the lamp were nearly as good as those at a dis¬ 
tance. 
During the past winter and spring, commencing on 
the 16th of January, experiments were tried under 
different conditions. The lamp was connected with 
the street lighting system, which was continued only 
for a few hours each night, and not at all on moon¬ 
light nights. The leaves of Radishes in the lighted 
house were larger, but the tubers were the same in 
both houses. Peas were most fruitful in the dark 
house, Lettuce was fifty per cent, better at the end of 
three weeks in the light house than in the other, 
and was fit to cut in a month, while that in the dark 
house took a fortnight longer to grow to the same 
size. The experiment was repeated, after transfer¬ 
ring the lamp to the house which had formerly been 
the dark one, with like results. Verbenas, Petunias, 
Primulas, Heliotropes, Tulips and others were sub¬ 
jected to the electric light in the same way. The colours 
of various Tulips were intensified, but faded again in 
the course of four or five days. The plants had 
longer stems and larger leaves than those in the 
dark house. Varieties of Coleus gave rise to some 
interesting facts. After two nights within 3 ft. of 
the lamp, the red sorts became yellow, brown be¬ 
came green, green lost its brightness, and dark 
purple became glossy-black. The shaded portions 
of the leaves remained unchanged, so that with day¬ 
light the exact outline of the shaded portion could 
be easily defined for some days afterwards. So 
varied have been the results with different plants 
under different conditions, that it is evident many 
more experiments must be made before any definite 
conclusion can be arrived at, as to whether the elec¬ 
tric light can be put to any practicable and useful 
purpose with profit. This will form the object of 
future experiments which are to be undertaken. 
THYMUS BROUSSONETII. 
Although by no means the tallest species of Thyme, 
the palm must be given it for size of flowers, which 
are of a bright rosy-purple, and as large as those of 
a Calamintha. The leaves are also relatively large 
and oval, or the uppermost ones constituting the 
bracts surrounding the flower heads are ovate and 
more or less concave. Curiously enough when 
bruised the stems and leaves emit an odour very 
similar to that of T. vulgaris, although so very diffe¬ 
rent in many respects. The stems vary from 4 in. to 
6 in. high, and are surrounded with shorter pro¬ 
cumbent barren shoots which never seem to form a 
matted tuft as our native plants of the same genus do. 
A hardy plant so neat in habit and so showy might 
well be extensively employed in various places and 
positions such as borders in sunny, well-exposed 
aspects or upon rock-work, which is the most suitable 
home for creeping plants of this kind. A flowering 
specimen may be seen even now in the herbaceous 
prpund at Kew. 
EARLY AUTUMN TINTS. 
Spring, summer, autumn, and winter are all indicated 
by the ever varying tints of the foliage of different 
trees and shrubs whether native or exotic, and which 
have been collected from all parts of the world where 
the climate is akin to our own or nearly so. There 
are some even amongst our native trees which show 
unmistakeably that the season is on the wane by 
September and even earlier if the summer has been 
a dry one. Amongst these are the Lime trees, whose 
fading brown or yellow leaves are not particularly 
attractive because scattered, and their tint never 
decided enough. In the same category may be 
placed the Laburnum, Hawthorn, and various others 
which have long been shorn of their pleasing green 
hue. 
More attractive in every way are the green, crim¬ 
son, and dark bronzy hues of the Virginia Creeper as 
it scales the front of some building and hangs down 
in leafy festoons from the eaves and around the win¬ 
dows, or when it seems strangling some old and 
half-dead tree. Its congener, the Japan Ivy (Vitis 
tricuspidata), is at the same early period of the year 
equally suggestive of a coming change, but crowning 
the autumn with a glory of its own. Where the 
slender shoots with small leaves go creeping thinly 
over the wall, the leaves glow with a ruddy bronze 
showing off’ the mor. vigorous shoots to advantage. 
The leaves on the latter attain a large size, and are 
of a shining light green with three lobes resembling 
Ivy at a short distance, and indeed a good substitute 
for it, except in winter when the leaves have fallen. 
A rather dry soil, and full exposure to light, favour a 
rich and early colouration much more than do rich 
soils in shaded positions, facts which planters should 
always bear in mind. 
A good deal depends upon soil and climate as to 
what hue the foliage of certain trees will assume. 
This is well known to those who have seen the 
American Maples and other trees at home, where 
they assume glowing tints and hues they never do 
under British skies. On the contrary the foliage of 
the Norway Maple in the United States drops with¬ 
out ever changing colour. Under certain conditions 
in this country it assumes a ruddy bronze even in 
September, while in the north, just before the final 
fall, the whole tree assumes a beautiful clear yellow 
conspicuous at a great distance, and the more so when 
in juxtaposition to foliage of a more sombre hue. 
Equally early as the Virginian Creeper and the Japan 
Ivy comes the autumn beauty of the Tupelo tree 
(Nyssamultiflora). All through the summer months 
there is nothing to distinguish it from a Cherry, a 
Laurel, or something of that nature, but by the middle 
of September the glowing crimson and orange of the 
leaves attract from afar. It is allied to the Dogwood 
(Cornus) but is rarely seen in collections of trees. 
Later on the five-lobed leaves of the Liquidambar 
will be aglow with similar hues, and being a taller 
tree is even more effective in the landscape. 
In striking contrast to the above may be mentioned 
the rich dark green hues of the Horse chestnuts, especi¬ 
ally the red-flowered (CEsculus rubicunda), also the 
Black and Lombardy Poplars, the False Acacias, So- 
phorajaponica.the Colchican Maple, the Elms, parti¬ 
cularly some of the small-leaved forms of the English 
Elm, and various others. The London Plane is as 
bright as it was at midsummer, and contrasts with 
the dark tints of the trees just mentioned. The 
White Willow in its typical form still wears a silvery 
silky hue, but it is less often seen than the variety 
Salix alba coerulea, which still maintains a wealth of 
bluish, long, finger-like leaves. Even the Scotch Fir 
and the Atlantic Cedar still wear their cheerful 
summer garb of a silvery grey or glaucous hue, which, 
in the case of the former at least, must soon give 
place to a darker and more sombre tint. 
Early autumn hues of another kind must not be 
overlooked in the wealth of ripening hips, haws, and 
berries of various kinds which deck the hedgerows 
and woods by the waysides as well as the well-tended 
gardens or pleasure grounds. Single Roses of 
various kinds are loaded with red, scarlet, or black 
fruit according to the species. The common Bar¬ 
berry is aglow with thousands of bright coral red 
fruit suspended in clusters from every spur and 
shoot. The dull dark-red haws of the common 
Hawthorn contrast strikingly with the brilliant red 
ones of the Fiery Thorn. The long straggling shoots 
of the Bittersweet, or those of the Red or Black 
Bryony, scrambling over the hedges, are almost as 
attractive with their loads of red berries as Lycium 
barbarum on the fences of villa and other gardens. 
Planters during the season now commenced, would 
do well to consider the effects they can produce at 
different seasons by the employment of frees and 
shrubs of particular kinds . — Ta rns 
