The herald., 1894-01-01
Mr. PURCELL ON IRRIGATION
Views of One Who Has Made
1t a Study.
The Much Disputed Question of the
Water Supply.
The Duty of Water Presented in Most
Attractive Manner-some sugges-
tioDs on the Area Which May
Be Supplied.
[BY GERvAIsE PURcELL.l

interesting ana many-blQeO featur6d hB
irrigation. Some eminent philosophers
have gone 80 far as to nuggest that it is
the duty of man to conserve the copious
rains that fall and utilize them in time
Of drought. Canon Kingsley, the poet
novelist and disciple of muscular
Christianity, is reported to have child 8
deputation of farmers, who besought
him to pray for rain, by replying that
he would not insult the Almighty by 80
doing. "Where," he cried, sis that
rain he sent you month ago and that
you in your improvidence let run into
the sea?'
However, in this age of enlighten-
ment when the farmer is educated far
above his predecessors when the bene-
it's OF conserved water supply. avail
able at the proper moment, have been
demonstrated beyond a peradventure,
it no longer cslls for Canon Kingsley
to tell us that irrigation means GER
tainty and certainty means wealth,
happiness and prosperity Why this
knowledge should have lain so long
we know from the ruins OF ancient &C.
queducts and dams that irrigation,
widespread and based on thorough
knowledge of the science of hydraulics,
was practised in prehistoric times in
India, Asia Minor, China and the
Americas.
What became of these races go we'll
versed in scientific agriculture? Why
/ have they disappeared and left no trace
That they were not warike is evidenced
by this vast knowledge of the arts OF
peace. The sapi Y may be that being
peaceful they wore industrious and ac-
cumulated wealth that drew upon them
the attention of robber bands of no.
mada, who destroyed whilst they fat
tened OF the stores of their more pros
porous neighbors.
! Egypt, British India, and Ceylon, in
the order written, represent the Oldest
known and continuous systems of irrl-
cation on our planet. The works, both
ancient and modern, in these countries
are eeries of vast and instructive OBJ
! ject lessons in the science OF irrigation,
and the hydrostatician who is thoroughly
versed in the expedients adopted in these
countries, and who has a mind broad
enough to enable him to modify and fit
his knowledge to the diversified circum-
stances OF another country, has here an
unbroken line of precedent and example
sufficient to enable him to cope with
any local peculiarity he may encounter.
To hope to reproduce in the arid regions
of the United States. with it's high paid
labor, the slave created colossal works
of Aeiatic countries is futile, but we may
we'll learn from them and use to our ad-
vantage the lessons taught by the great
truths that lie at the base of all scien-
ti6c effort.
r The late irrigation congress, held in
| this city, has set thinking men to giving
attention to many points brought out in
blazing letters, like the writing on Bel
shazzar's wall. Notable amongst others
was Major Powell's statement that the
land in the arid regions is lar in excess
of the amount OF water available for its
successful irrigation. This statement
brought down furore Of protestation
and contradiction from all sides; yet, if
l understood the gallant Major at all, he
merely neaDt to say that given the old
crude methods of irrigation as vehicle
for the distribution OF the waters of the
arid regions, as basis of calculation,
and the land in acres, the latter is vastly
in excess of the duty OF the former.
And who would have it otherwise ?
Clearly no one, for then would one of
the greatest stimulants to progress be
removed.
Here is opened up at once field for
scientific research in demonstrating
how and in what quantities on different
soils the best results may be obtained by
the use of the minimum amount OF
water per acre.
When we reflect that in steam the
amount of coal consumed to produce a
horse power has in 80 years been re-
duced from IL pounds per h.p. to or 2
pounds per h.p.. who will have the
temerity to say that the water available
in the arid regions will not in like
period irrigate IL acres where it now
barely euffices for one?
TIE DUTY OF WATER.
The various irrigation territories OF
the old and new worlds have unit of
measurement comprising quantity and
time which is popularity adopted in each
locality to express the water required to
successfully irrigate given area of land.
The scientist, however, ae a rule, uses
for his unit the cubic foot per second,
which is equivalent to fifty OF our Cali
fornia miners inches. There are three
general methods OF expressing the duty
done by THE unit, one or other OF which
is adopted for use, viz:
l. The area irrigated per unit of flow
during the irrigating season.
2. The cubic quantity of water per
unit OF area.
8. The total depth OF the several
waterings over the entire area irrigated.
Any one of these three methods is
equally efficacious and its use is gov
erned bv local custom.
In every new arid district when first
brought under water system, general
principles alone can be applied until
time and experience demonstrate:
First-The character and condition of
the soil and subsoil.
Second-When properly located hy-
geographic instruments teach what the
rainfall. evaporation and temperature
average over term OF years.
Third-The best method OF application
to be employed.
Fourth-The kind of crops best suited
to the particular locality in contempla-
tion; and
Fifth--The depth Of the plane OF sat-
uration below the coil to be irrigated.
From careful study Of theee five
conditions can be deduced system of
irrigation economics that will enable us
in future years to devise means whereby
the present supply of water may be
made to do a very much larger duty