204 
THE CULTIVATOR. 
June, 
enters this mound, and passes the water through the 
interval. The land on each side of the main car¬ 
rier is laid out in beds of forty feet in width, at 
right angles, lengthwise, with the main carrier. 
The beds are made quite crowning in the centre, by 
frequently back furrowing the soil with the plow. 
Sectional ditches cut through the centre or most 
crowning part of these beds, take the water from 
the main ditch, and pass it the entire length of the 
beds. Frequent little openings are made in the top 
of the sides of these sectional carriers, through 
which the water flows, and then it spreads each way 
from the ditch, over the entire surface of the beds, 
passing into the dead furrows, when used profusely, 
and by them it is carried to a main trench to be con¬ 
ducted to land on a lower level, or else back into 
the river. Flumes and gates #re placed in the main 
carrier at suitable intervals, and also at the mouth 
of the side carriers, so that the water can be chan¬ 
ged from one section to another, as desired. 
It struck me, upon viewing these graduated mea¬ 
dows, that they were in the long run, of a cheaper 
construction than those where the surface is left in 
its natural state. Once done, they are right for all 
time, the irrigation is easier managed, the water 
more perfectly distributed and drained off, and its 
effects, in consequence, are more beneficial. 
I should remark that all the irrigated fields which 
I saw in my recent journey are invariably of a light 
dry sandy soil, with an open subsoil. It is found, 
however, in practice elsewhere, that almost all soils 
are benefitted by irrigation, if water does not stag¬ 
nate for want of proper drainage. 
Sinclair remarks that “irrigation is not restricted 
to any particular* description of soil. Land natu¬ 
rally wet may be greatly improved by it, when ac¬ 
companied by drainage, and it is equally beneficial 
to that which is dry. Rich loams produce the great¬ 
est crops, even though waters be not of the first 
quality. Peat bogs, when properly drained, will 
likewise yield good crops. Irrigating adhesive clays 
is expensive, and the benefits from it do not so soon 
appear; but it is evident, from a meadow near Long- 
leat, that even this sort of land may, by good man¬ 
agement, be thus rendered more fertile; and it is 
well known that some of the best meadows in Glou¬ 
cestershire, and at Woburn, are upon a clayey sub¬ 
stratum. The most suitable soils, however, are 
those of a sandy or gravelly nature; more especial¬ 
ly when they can be irrigated by muddy streams, 
the sediment of which corrects their excessive open¬ 
ness. Indeed, by means of the warm and rich wa¬ 
ters of a low, fertile and populous district, impreg¬ 
nated with mud, and full of animal and vegetable 
manures, almost any soil may be converted into a 
rich meadow.” 
Finally, the theory of the advantages of irriga¬ 
tion is thus summarily stated by Stephens, in his 
Book of the Farm. “ Could the hand of man,” he 
remarks, “distribute manure around the roots and 
stems of grass as minutely and as incessantly as tur¬ 
bid water; could it place a covering of woolen tex¬ 
ture upon each blade and around each stem of grass, 
as completely as water can embrace each plant and 
keep it warm; could it water the grass as quietly 
and constantly as the slow current of irrigation ; and 
could it wash away hurtful matter from the soil as 
delicately from the fibres of the roots of grass as 
irrigating water, there would be no need of irriga¬ 
tion ; the husbandman could then command at will 
verdant pasturage for his flocks and herds, through¬ 
out the year, and in the driest season. His mechan¬ 
ical agency would be as effective as irrigation; but 
.constituted as the relative state of things at present 
are between man and the action of physical laws, 
he employs irrigation as an instrument of his will, 
and induces Nature to assist him in maintaining his 
live stock by an application of her peculiar mode 
of acting, under his own guidance, but in which she 
undoubtedly displays her superiority over him, both 
in perseverance and dexterity.” 
I have prolonged my article to a great length; 
but believing that the subject of irrigation is not 
very generally understood, and that the art is much 
less practiced than it should be where so many ex¬ 
cellent natural facilities for it exist, I have thought 
it advisable to be at considerable pains in citing au¬ 
thorities sufficiently to explain its principles, and 
turn attention to its practice. F. PIolbrook. 
BraUnono ’, Vt., April 30, 1850. 
®lie Qortiaxltnral IBtpartmmt. 
CONDUCTED BY J. J. THOMAS. 
Pear-Tree Blight. 
John Randolph once remarked to his physician, 
“in the multitude of counsellors there is confusion ,” 
which is true when hasty and partial opinions are 
given. This is strongly illustrated by the discus¬ 
sions on the Pear-tree Blight. 
“ It is always caused by the freezing of winter,” 
says one. “ It is always produced by the burning 
heat of summer,” says another. “It is owing to 
succulent growth, produced by injudicious cultiva¬ 
tion,” asserts a third; “it comes on like a pesti¬ 
lence or the potato rot, uncontrolled and unaverted 
by any skill,” responds a fourth. Some have dis¬ 
covered that it is caused by an insect girdling the 
interior bark; others, that it results from the poi¬ 
sonous sting of an insect in the branches. Many 
maintain that particular varieties only are strongly 
liable to this disaster, and many more, that it attacks 
all sorts alike. 
In addition to previously advanced opinions, we 
have received a communication from E. J. Genet, 
of Greenbush, N. Y., in which he confidently ad¬ 
vances the belief that he has discovered the true 
cause; but the length of his communication, and 
the very narrow limits of the Horticultural Depart¬ 
ment of this paper, preclude its publication entire. 
We can furnish only an abstract of his theory and 
observations. At or a little before mid-summer, in 
the absence of dew for several nights, he observed 
liquid drops falling from a pear tree, which were 
subsequently found to proceed from minute aphides 
thickly covering the shoots or branches, and which 
had at first escaped notice from the identity of their 
color with that of the pear bark. The varnish 
which these insects exude, is regarded as a poison, 
absorbed by the pores of the bark, and preventing 
also the natural perspiration. These insects were 
observed to continue for about ten days, when they 
disappeared. They are doubtless worthy the atten¬ 
tion of fruit growers, and may under certain cir¬ 
cumstances produce the death of the tree or branch¬ 
es ; but it would be deciding from too limited data 
to say that this is the usual or universal cause. Ob¬ 
servations must be made with great judgment and 
accuracy through all parts of the country,—through 
a long series of years,—through all the variations 
of seasons,—under all modes of cultivation,—in all 
varieties of soil,—and in various latitudes and cli¬ 
mates, to enable any one to overthrow all previous 
opinions, and to establish a single theory applicable 
alike to all cases. But it is always interesting and 
