CLIMATE, HORTICULTURE, AXD AGRICULTURE. 
473 
Excessive exhalation is very injurious to many 
of the processes of vegetation, and no small 
jiroportion of what is commonly called blight, 
may be attributed to this cause. Evaporation 
increases in a prodigiously rapid ratio with 
the velocity of the wind, and''any thing which 
retards the motion of the latter, is very effi- 
cacious in diminishing the amount of the 
former ; the same surface, which in a calm 
state of the air would exhale 100 parts of 
moisture, would yield 125 in a moderate 
breeze, and 150 in a high wind. The dry- 
ness of the atmosphere in spring renders the 
effect most injurious to the tender shoots of 
this season of the year, and the easterly 
winds especially are most to be opposed in 
their course. The moisture of the air flowing 
from any point between N. E. and S. E. 
inclusive, is to that of the air from the other 
quarter of the compass, in the proportion of 
814 to 907 upon an average of the whole 
year : and it is no uncommon thing in spring 
for the dew-point to be more than 20 degrees 
below the temperature of the atmosphere in 
the shade, and I have even seen the difference 
amount to 30 degrees. The effect of such a 
degree of dryness is parching in the extreme, 
and if accompanied with wind is destructive 
to the blossoms of tender plants. The use of 
high walls, especially upon the northern and 
eastern sides of a garden, in checking this 
rril, cannot be doubtful, and in the case of 
tender fruit trees, such screens should not be 
too far apart." 
Here we have the horticulturist's business 
pointed out very clearly, in a manner which 
defines the science. It is the business of 
theorists to reconcile, as well as they can, our 
facts to their theories, and horticulturists may 
profit by inquiring to a certain extent into 
the causes of well known effects ; but, were 
practical men to attempt to go beyond certain 
points, they would utterly waste three-fourths 
of their time in seeking that which, when 
obtained, would not be worth the having. 
They may know that cuttings strike best when 
shaded from the sun and protected from the 
wind, and some would be content without 
going further. If they were content with 
learning that the sun and wind would cause 
excessive evaporation, and deprive the cut- 
tings of the juices they possess while they 
had no means of obtaining a fresh supply, 
the knowledge would be useful ; but if they 
attempted to follow the philosophers through 
a thousand intricacies, they would have to sacri- 
fice much valuable time for knowledge to them 
under every circumstance useless, and follow 
an ignis J/itiius which would take them from 
their business into a labyrinth from which they 
Would hardly be able to extricate themselves. 
The practical horticulturist may wisely study 
the locality of plants, that he may be able to 
supply that which he knows will suit them; 
hut he must no more attempt to imitate 
nature as the perfection of treatment, than he 
must treat the rose after the fashion of the 
hardships they undergo in the hedges. The 
plant which comes from the tropics may 
safely be supplied with a climate as nearly as 
possible similar, because the gardener knows 
it to be at least a safe one, but he has then 
only half done his work. He must learn to 
treat it in the best way, and that may be 
very different from that which nature sup- 
plies even at the tropics. 
In this country the fruits of hot climates 
are produced, notwithstanding all the natural 
disadvantages we have to contend with as to 
our climate, in perfection, and that is more 
than can be said of the very locality from, 
which they are imported ; and if it be a fruit 
not artificially or regularly cultivated at home, 
that is, where it is indigenous, they will be 
produced much finer; but if the horticulturist 
in the West Indies cultivates the pine apple 
with the care which is bestowed on it in this 
country, he will have one advantage naturally, 
which we have to imitate ; nevertheless, the 
pine apple grown in perfection in England, 
far surpasses in richness of flavour the pine 
apple grown in the fields of the West Indies ; 
experiment, the mother of improvement, and 
perseverance, the harbinger of success, accom- 
plish much that nature unaided, even where 
plants are indigenous, never did achieve ; and 
we have a hundred times seen and eaten the 
grape in higher perfection in England, than 
it ever arrived at in its native soil and climate. 
Plant a heath in the very best locality of the 
Cape, and is there a practial gardener who 
will venture to dispute that we can fairly beat 
it in England ? We write not of hybridizing 
nor a change of races, for the same thing 
might be done at Botany Bay, but we allude 
to the fair growth of a known indigenous 
species or variety. Larger plants may be found, 
and are found, like our great bushes of furze, 
blooming in all their beauty and growing 
luxuriantly; but they are, in respect to age, 
Methuselahs to our youthful specimens ; and 
we seriously doubt, if expense was no object, 
whether there is a single valuable production 
that might not be grown in Great Britian, in 
perfection. We know we are limited for 
sun and light, we know that many of the 
apparent requisites, if we arc to judge by the 
countries they have left, are wanting, yet we 
know also that the cost is the only limit to 
the production of a thousand gigantic subjects, 
which rear their heads in tropical forests. It 
is in the supply of all these requisites by arti- 
ficial means, or of something equivalent to 
them, that the British horticulturist shines ; 
