CONTEMPORARY WRITINGS. 
239 
Manuring the Atmosphere of Hot- 
houses. — The collection of orchidaceous plants 
in the garden of the Horticultural Society are 
in the best possible health ; the foliage being 
of a remarkably deep green colour. This cir- 
cumstance Mr. Gordon, the superintendent, 
ascribes to his supplying ammonia occasion- 
ally to the atmosphere of the house. Having 
first wetted a bit of pure carbonate of ammonia, 
about the size of a bean, he rubs it on the hot 
water pipes, waves his hand backwards and 
forwards once or twice, to disperse the fumes, 
and the work is done. Besides adding to their 
green colour, he is of opinion that this impor- 
tant manuring principle otherwise acts bene- 
ficially on the plants. It must, however, be 
used with caution, or it may do more harm 
than good. Mr. Gordon applies it in the 
evening, just before the house is steamed. — 
Gard. Chron. 
Vegetable Poisons. — It so happens that 
all the most virulent poisons are of vegetable 
origin. There is the deadly aconite, which 
kills in small fractions of a grain ; and strych- 
nia, a fourth part of a grain of which has 
killed a wild boar in a few seconds ; and prus- 
sic acid, so prevalent in many botanical tribes. 
Then there are the deadly alkalis of hemlock 
and tobacco, and oxalic acid of treacherous 
fame, all derived from the vegetable kingdom ! 
And yet the empiric physicmonger, forsooth, 
imposes on the credulity of an ignorant com- 
munity by vaunting the innocence of vegetable 
medicines ! Why, before the rapidly mortal 
action of some of the vegetable educts we have 
mentioned, arsenic, that terror of the mineral 
kingdom, is innocence itself, and sublimate is 
impotent. — Chemical Times. 
Erica carnea. — This is certainly the most 
valuable and interesting of hardy Heaths. It 
flowers early, is compact and dwarf in habit, 
and, when grown in quantity, enlivens the 
American borders and beds at a season when 
ornament is most required. This species is 
well adapted for a bed or group. It also suc- 
ceeds in large pots or vases, if kept cool and 
moist at the roots and replaced early. It is 
valuable for replenishing winter bouquets, 
especially in cool rooms. It may not, perhaps, 
be generally known that if half the plant or 
plants be covered with soil (or probably with 
any other light material), for a period before 
the flowers attain their colour, it will blanch 
them to such a degree as to present the appear- 
ance of a distinct pale or white variety, form- 
ing a lively contrast with the rosy-pink hue of 
the unblanched plants. This Heath may be 
planted in the ordinary flower borders, using 
. as a substitute for peat or heath-mould, one- 
haif finely sifted pure unfermented leaf-mould 
(divested of its earthy matter), the remainder 
equal portions of fine river or white sand and 
sandy loam, well mixed. This compost should 
be well pressed previous to the plants being 
firmly planted in it. — Gard. Chron. 
New System of Vine Culture. — The 
following is a translation of a paper on this 
subject, lately read to the Academy of Sciences 
of Paris, by M. Persoz : — " The new process 
which I propose for cultivating the vine, in- 
asmuch as it enables us to make use of half 
of the land for growing nutritive plants, may 
at first sight appear to difier completely from 
the plans now adopted in vineyards. Such, 
however, is not the case, and as those who 
have studied the various methods pursued in 
different countries will see, several of the 
recommendations here made have been already 
followed in practice ; I acknowledge this the 
more readily, as it enables me to appeal, as a 
proof of their usefulness, to results obtained 
by long experience. In one respect, my plan 
differs from every other ; for I propose that 
all the vine stocks in a certain space of ground 
should be brought together in a trench, where 
by one chemical action the wood, and by 
another the fruit, may be induced to form. 
This I propose in consequence of having, by 
direct experiment, satisfied myself that, of the 
manures which are fit for the culture of the 
vine, some serve exclusively for the increase 
of cells, i. e. of wood, and that others cause 
the development of the flower bud (fruit or 
grape); and the actions of these substances, 
instead of both going on at the same time, 
ought to be successive. By the application of 
these principles, the growth of the wood can 
be stopped at pleasure, whilst, by the ordinary 
methods, the same effect can only be produced 
by artificial and empirical means. When it 
is wished that wood should be developed, the 
vines must be placed in a trench and covered 
with three or four inches of earth, with which 
have been mixed, for every square yard of 
the surface of the trench, 8 lbs. of pulverised 
bone, 4 lbs. of pieces of skin, leather, horns, 
tanners' refuse, &c,, and l| lb. of gypsum. 
When the wood is sufficiently formed, which 
will be in a year or two, according to circum- 
stances, the roots must be supplied with salts 
of potash, in order that the fruit may be pro- 
duced. For this purpose it is necessary to 
spread over the trench, at a distance of three 
or four inches from the buried wood, for 
every square yard of surface, 5| lbs. of a 
mixture formed of 8 lbs. of silicate of potash, 
and 2| lbs. of double phosphate of potash and 
lime. The trench is then to be filled up, and 
the roots have as much potash as they will 
want for a long time. To prevent, however, 
the exhaustion of the potash, it is as well to 
spread every year at the foot of the stools 
a certain quantity of the marc of grapes ; 
this marc, containing 2.5 per cent, of carbon- 
