IRRIGATION. 
tiiat motive, and the support of tlie revenue 
produced by farming of the canals, do qot 
allow the smallest despoliation to pass tiii- 
punished. AVe are assured, by the best au- 
thorities, that the whole of the pasture 
lands in the Milanese exhibit uncommon 
fertility ; and that the canals ai'e so very ex- 
tensive, and the branches from them so nu- 
merous, that few need complain of a want 
of water for irrigation. These works are 
known to be of no modern date ; some have 
existed for centuries, chiefly appertaining 
to monasteries ; their waters being let out 
by measure to fertilize tlieir adjacent lands. 
The great canal, known by tlie designation 
of Vecchiabbia, was in a flourishing state 
early in the eleventh century, beyond which 
we do not know what might have been its 
age. In 1220, the great canal of Adda, 
which waters the plains ot Lodi, was finish- 
ed ; in 1305, the canal of Treveglio, which 
communicated with four others of very an- 
cient workmanship, was completed ; and in 
1460, the canal of Martesano, extending 
thirty-two English miles : in this aqueduct, 
besides the main branch, of thirty-five feet 
in width, there were made nineteen scari- 
catori, or lesser canals, w'hich served, when 
tlie waters rose very high, to draw off tlie 
surplus, so as to prevent injury to the main 
line, and to prevent inundation along its 
course: when the latter returned to a 
more tranquil state, the scaricatori, which 
w'ere not so deep as the main line, served 
to supply it with what remained of their 
contents. . 
It is worthy our notice, that although the 
Italian aqueducts have, to our certain know- 
ledge, been duly supported for upwards of 
eight centuries, by a race of people far be- 
neath us in the more noble science's, in 
wealth, in population, and in many other 
circumstances in which we pride ourselves ; 
yet that Britain cannot boast of one aque- 
duct, made exclusively with the important 
view to improve her agriculture ; though it 
would be as easy to shew a thousand situa- 
tions where such canals would double the 
value of the lands adjoining, as it would be 
to prove that such value would be doubled. 
It is, indeed, only in a few counties, that 
irrigation is carried on to any extent; 
though we may in various places see partial 
adoptions of this most beneficial practice : 
yet we daily obseive situations naturally of- 
fering this advantage, without the smallest at- 
tempt being made to retain streams which, 
from elevated situations, glide with some 
velocity through deep valiies, whose very 
borders, perhaps, are verdant, but whose 
more retired parts would be doubled or tre- 
bled in value, by the influence of that ele- 
ment, which is allowed to pass by unheed- 
ed, to be lost in some marsh, or eventually 
in tlie ocean ! It is true, that, in some parts, 
irrigation is not understood ; and, that it is 
not always practicable to obtain proper 
assistance ; whence many, who would wil- 
lingly water their meadows, are prevented 
from taking advantage of streams capable 
of effecting the intention. For the benefit 
of such persons, in particular, as well as of 
our readers in general, we shall endeavour 
to simplify, even this simple process, in such 
a manner as may prove perfectly intelligi- 
ble ; and, by shewing with what ease irri- 
gation may be carried on, induce a portion 
of our landholders to attempt, even with- 
out professional aid, or the tuition of expe- 
rienced persons, that retention and gradual 
distribution of waters whose sources are 
sufficiently elevated, which may favour 
such a slight and temporary inundation, as 
may give vigour and freshness both to the 
soil and to its produce. 
ATe shall divide this subject into two dis- 
tinct heads, viz. simple, and compound ir- 
rigation ; observing that the former may be 
practical in 'various modes separately, as 
will be shewn, and that they may be blend- 
ed so as to come under the second term. 
ATe shall also, by way of preparation, give 
the reader an insight into some modes of 
cutting off, or of supplying water, from 
sources of different heights, and under dif- 
ferent circumstances : by this means, rvith 
a moderate portion of judgment, the novice 
in this art may speedily acquire sufficient of 
the principles to answer his own purposes, 
at least, if not to form a correct opinion of 
most of the cases which may come under 
his observation. 
The greatest difficulty we generally ex- 
perience, is from the water being below 
the level of the lands over which it is to be 
conducted. In many instances, the springs 
whence streams are fed, lie very deep; 
and, though copious, for want of a sufficient 
inclination of their beds, move very slowly. 
In other parts, jealousy of improvement, 
personal enmity, the owner being a minor, 
or insane, and the property in the hands of 
trustees, or the estate being in Chancery, 
mortgaged, &c, perhaps debars the possibi- 
lity of taking advantage of some peculiarly 
favourable fall, from which the water might 
be conducted with perfect facility and ef; 
feet, over inclined planes, which, by their 
