December 12, 1878. ] 
JOURNAL O@ HORTICULTURE AND COTTAGE GARDENER. 441 
WEEKLY CALENDAR. 
Day, Day Average s Ciock 
, EP ee erat x Sun Sun Moon | Moon | Moon’ Oc Day 
een Oe DECEMBER 12—18, 1878, paces DenaEUne men Risesi: || Sets misesallagsatee eel plore out 
Day. ,Night Mean] h. m.| h. m.| h. m.| h. m|/ Days. | m. s. 
12 | TH | Annual Meeting of National Rose Society. 48.0 | 37.0 | 42.5 Teo O So AON iG) 29). Ona: 18 6 41] 346 
13° | FP Queckett (Microscopical) Club at 8 P.M. 47.5 | 36.5 | 420 | 8 0} 3 49] 7 51/10 41 19 5 (365) 547 
4 is Royal Botanic Society at 3.45 P.M. 46.9 | 343 | 406 | 8 1] 8 49] 9 11]/11 11] 20 5 47 | 348 
15 SUN | 3 SUNDAY IN ADVENT. 47.0 | 33.6 | 40.3 8 2 3 49 /)10 32] 11 18 21 4 33 | 349 
16 | M London Institution at 5 P.M. 46.5 | 382.9 | 39.7 8 38) 38 49 | 11 54] 11 33 29 4° 9 | 350 
W7 | Tv | Royal Horticultural Society—Fruit and Moral Com- | 45.9 | 34.0 | 39.2 | 8 4] 3 49 | mom. /11 48 | © 3 40 | 351 
18 | W Society of Arts at 8 P.M. [mittees at 11 Am. | 45.8 | 33.7 | 39.7 | 8 4] 3 49] 1 17] Oa3 24 3 10 | 352 
34,59, 
From observations taken near London during forty-three years, the average day temperature of the week is 46.89; and its night temperature 
PETROLEUM AS. AN INSECT KILLER. 
HE inventors of’ many excellent insecticides 
deserve well of their country, and I hope 
they have realised handsome profits. If not, 
it is certainly too late in the day now, for 
none of the antidotes that I have tried can 
bear any comparison with petroleum for 
efficacy, cleanliness, and cheapness. Mealy 
bug, scale, and even the terrible red spider need 
frighten us no longer, for one dose will stay 
-) their progress and two or three will make an effectual 
(clearance. 
That petroleum or paraffin is distasteful to insects 
“may seem a small affair to the uninitiated and even to the 
learned physiologist, but to practical gardeners who have 
to supply plants by scores of thousands it is of far greater 
importance than whether certain plants are carnivorous, or 
whether all of them absorb water from the atmosphere 
through their leaves ; for however these great questions may 
be decided by learned men, it will matter comparatively 
little to the plodding gardener, whose practice already meets 
the requirements of the plants as far as these matters are 
concerned whatever may be the theory. 
The discovery of this simple remedy for insects I do not 
hesitate to characterise as of greater importance to the 
gardening world than anything we have had for years. It 
is comparatively new to us, and therefore we do not yet 
fully estimate its value. But just realise the fact that the 
sponge, pointed stick, sulphur, soft soap, and all filthy com- 
pounds are superseded ; that people with old tumbling-down 
houses and walls, which have hitherto been places of security 
for the greatest plagues gardeners are troubled with, are 
henceforth to be on a par as regards cleanliness with those 
possessing the best modern structures ; that the syringe, 
which at present does so much harm in the hands of the 
inexperienced, may be used less and less; that in the busy 
spring, when there is often three days’ work to be done in 
ten hours, and the insects show us no consideration, we can 
annihilate them almost in a moment at the cost of a few 
pence, and turn our labour to a more visible account ; and 
it will be seen that it is no small blessing this simple dis- 
covery brings to us. Although I have satisfactorily proved 
the fact for myself, it seems too good to be true. We 
shall need to dream no more, when after some months’ hard 
work of body and mind to get a house clean, that one of 
our assistants has broken a pot and replaced it with one 
from an infested spot; that another has tied up a shoot on 
a Cucumber plant where there was just a-suspicion of 
spider and gone immediately into the early vinery to pull 
off a tendril or two, or some other similar little thoughtless 
act which destroys in a moment the work of months and 
even of years. 
I daresay many people will lay claim to this important 
discovery, and possibly more than one may have hit on it 
at the same moment. I can only trace it to Mr. David 
Thomson. 
The proportions to use are one wineglassful of petroleum 
to a gallon of water. They do not mix together well, but, 
No, 924—VOL, XXXV., NEW SERIES, 
as has often been advised in “ Work for the Week,” if two 
or three squirts with a syringe are made into the vessel 
containing the mixture and then immediately one syringe- 
ful on to the plant, and afterwards alternately squirting one 
into the vessel and one on to the plant, it will be sufficiently 
mixed for all practical purposes. Thus used it will kill 
red spider and all but the very oldest scale, although its 
shelly covering has become somewhat hardened, while it 
it will not injure the tenderest Ferns. I have no mealy 
bug to try it on, but from what I have heard I have not 
the least doubt of its effect on that terrible pest. 
Dipping the plants will not do so well as syringing. I 
had some Ferns dipped in a tub containing twelve gallons, 
and although one operator was agitating the mixture with 
a syringe all the time while another was dipping the plants, 
those first dipped appropriated all the oily substance from 
the surface of the water, and it remained on them some 
weeks and discoloured them. I do not think, however, it is 
this oily substance which is so fatal to the insects, but 
some other ingredient contained in the petroleum, and which 
mixes fairly with water, giving it a bluish colour ; for the 
mixture was almost as effectual after the oily substance had 
disappeared. i 
Everyone who has used soap or alkali for plant wash (and 
most of the mixtures which have obtained popularity con- 
tain them), knows that the glass and paint with which they 
come in contact are soon injured, the glass losing its trans- 
parency and the paint coming off. As far as my experience 
goes at present petroleum does neither of them the least 
injury.— WILLIAM TAyLor. 
PLUMBAGO ROSHA. 
Somer writers have condemned this plant as useless be- 
cause it is not adapted for cutting purposes, nor suitable 
for the decoration of rooms ; nevertheless it is highly worthy 
of being cultivated, especially by those who wish to have 
their houses attractive through the dreariest months of the 
year. Scarcely a flower is to be seen outdoors at this 
season of the year, therefore it remains for our stoves and 
conservatories to be made gay with flowering plants to 
afford the pleasure which our employers have the right to 
enjoy. 
Forethought and care are necessary in preparing plants 
for winter decoration, and the gardener has often to wait 
from six to nine months or more before he sees the returns 
for his labour. The demand for cut flowers has increased 
considerably of late years, and oftentimes more are ex- 
pected than can be produced with the means at our com- 
mand; this may be why Plumbago rosea is not more 
generally cultivated. We prepare some plants for the 
adornment of our houses, and others for the decoration of 
rooms and for cutting purposes. We know of no plant 
more suitable, nor that lasts longer in bloom, nor produces 
a more gorgeous effect when grown in quantity than this 
Plumbago. Each flower certainly is short-lived, but the 
flowers are produced in succession—as soon as one is faded 
another is opened, and thus their beauty is continued for 
a long time. 
No. 1576,—VOu. LX., OLD SERIES. 
