April 2, 1891. J 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
267 
Tines, will set under almost any system of management; but when we 
come to the majority of the large-flowering varieties more care is 
necessary, for the fructifying organs are of a different stamp, with 
a, more slender pistil, the stamens wider apart, and the pollen not 
nearly so freely produced, and I consider a few hours spent during the 
time the trees are in bloom in fertilising with a camel’s-hair brush 
amply repaid ; at any rate, by so doing one has the satisfaction of 
having adopted every available means to ensure a crop, however it may 
turn out. At the same time a moist condition of the air may be pro¬ 
duced by the orthodox system of management, equivalent to syringing 
the trees while in flower. To syringe a hou«eand leave ventilation on seems 
a singular process, for it is like trying to defeat the object you wish to 
attain, for a very large proportion of the moisture must escape.—J. J. C. 
As I am not troubled with the above mentioned pest on the Peach 
trees, and have never any difficulty in obtaining a good set of fruit, 
perhaps a few remarks will be acceptable. In my opinion trees are 
often checked from chills either from too free ventilation on cold days 
or syinging wdth water below the temperature of the house, and un¬ 
doubtedly as Mr. H. Dunkin remarks on page 230, houses are sometimes 
kept too hot and dry when trees are in flower. After a check in growth, 
from whatever cairse, green fly will soon appear, but provided trees are 
In good condition and properly treated I do not think there need be 
much dread of the aphis or of an inferior set of fruit. Previous to 
•expanding the lower and side flower buds ought to be rubbed off by 
degrees, and a hive of bees placed in the house, as bees are the best 
distributors of pollen that I can find. The house is kept at a tempera¬ 
ture by night 55° to 57°, by day 57° to 60°, running up by sun heat to 
65° to 70° according to weather. Should frost or very cold weather set 
in the temperatures are not kept so high. All the upper flowers must 
not be allowed to set, but thin them by degrees, and keep the young 
growths thinned at intervals also. After the fruit is well set they 0 U:!ht 
also to be thinned, leaving only a few more than the number required 
to ripen. As a rule there are far too many fruits left till after stoning; 
this is to allow for so many falling off, whereas if just sufficient was left 
for the trees to bear the dread of their falling would cease. 
The next critical period is the ripening, and Peach trees are often 
a’lowed to suffer from dryness, the result being that numbers of buds 
fall the following season. When fruit is gathered some of the old wood 
may be thinned, but not so severely as to check the trees ; they may 
also receive their final watering for the season. Except surface watering, 
•I only supply water at the following times, and I find it sufficient— 
namely, previous to b’ooming, previous to sti^ning, previous to colouring, 
and immetliately the fruit is gathered. The syringe is used freely 
except when the trees are in flower and when fruit is ripening. Soon 
after all leaves are fallen the trees may be tied in, cutting out what little 
wood is not required ; if disbudding has been done sufficiently little 
pruning is required. The borde^^s being cleaned and dressed, the trees 
may almost be left to take care of themselves till the season for flowering 
is again at hand.— Samuel Scott, Rathmore, Belfast. 
THE ARRANGEMENT OF HOT-WATER PIPES. 
Unfobtunately I have lost the first article by Mr. Hammond on 
the subject of heating by hot water as quoted by Mr. Williams from 
'Tlee Gardeyier, but have examined the subsequent controversy, which I 
'Consider alludes more to the principle of heating on scientific rules 
rather than to the subject of my article (page 179)— the best manner 
•of arranging the hot-water pipes in fruit houses, with a view to a better 
lequalisation of the heat. 
Will Mr. Williams say in what respect Mr. Divers’ objection is full 
of sound judgment? Objections may be raised to any plan, but 
•substantiating such objections with an improved method would carry 
much more weight. It is sometimes easier to find fault than it is to 
find the remedies. Again, Mr. Williams says, “ We believe that the 
primitive arrangement whith ‘Heating Reformer’ condemns is likely 
to prove a less evil than the system he advocates, but he fails to give 
the grounds of his ‘belief.’” With regard to the efficiency of the 
working of five flows into one return, how can Mr. Williams condemn 
the plan seeing that he has had no experience ? My opinion is if he 
saw the plan in operation with me he would want to imitate it. 
I have timed the circulation of the water round a vinery 27 feet long 
through five flows into one return since I last wrote, and find it took 
'Pne and a half minute to make the pipes quite hob equally throughout 
from the time the valve was turned on the flow pipe to admit of the 
circulation. In opposition to Mr. Williams’s case, where he states that 
three flows to one return do not answer at a distance from the boiler, 
we have a late vinery 30 feet long, the end of which is 100 feet from the 
boiler. This vinery is fitted with three flows and one return. From the 
•time the valve was turned on but six minu^es elapied before the pipes 
■were quite hot equally over the house. This fact proves much more 
than a mere verbal objection that it is not the principle of arranging 
the pipes which is at fault, but instances where it is not properly carried 
out, hence the objection (o the general phan. Experience on the spot 
will prove in ten minutes far more than an hour’s writing. 1 may say 
that we have a .span-roifed plant house fitted on each side with a single 
.flow and return pipe. This house is at no great distance from the boiler, 
but much difficulty is experienced in maiut lining the temperatuie 
above freezing point during severe weather. This is where there is an 
equal number of return and flow pipes. The non-succesj of the heiting 
■of this house is attributable to the faulty arrangement of the pi^ es. 
—HEATixa Repokmer, 
ARUM PALaESTINUM. 
It is not often we have occasion to give a representation of an 
Arum, but that here depicted (fig. 49) is so distinct and peculiar 
that it merits special notice. The plant was shown by Mr. Gold, 
High Ashurst Gardens, Dorking, and is remarkable for the possession 
of a velvety black spathe and spadix, 6 inches long each, and borne 
on a stem about a foot in length. The leaves are about the same 
height, the blades 6 inches long, lobed, and the same in breadth 
across the base. The spathe is tapering in form, purplish towards the 
base, deepening into black at the upper part. 
Arum palsestinum was discovered by M. Boissier near Jerusalem, 
and from there Messrs. Veitch & Sons of Chelsea introduced it to 
cultivators in this country. 
ON THE EFFECTS OF URBAN FOG UPON 
CULTIVATED PLANTS. 
[Preliminary report by Dr. F. W. OLIVER, presented to the Scientific Committee of the 
Boyal Horticultural Society, March 24th, 1891.] 
The investigation, as to which I am now drawing up an interim 
report, has been undertaken by the Royal Horticultural Society’s 
Scientific Committee, supportal by a grant from the Royal Society to 
meet the cost of apparatus, &c. The question of the effects of urban fog 
on plant life has come prominently before our town and suburban culti¬ 
vators, and the damage from this cause, which may formerly have been 
regarded as exceptional, is now admitted to be chronic and constitutes 
an ever-increasing source of dismay to all interested in horticulture. 
The action of the Scientific Committee in taking up this question is but 
the reflection of a general feeling amongst cultivators that something 
