17 
but not having a definite record, his is taken. The difference is not 
great. Some water was running nearly all the time, but in the in¬ 
tervals on the diagram showing none, the quantity was too small to 
show on this scale, and was generally the leakage from the gates 
and of no use for irrigation. The custom of Capt. Post in conduct- 
z 
Fig. 7. 
ing the irrigation, is to turn the water on a portion of the field and 
allow it to run for some time, his ditches and gates being so arranged 
that it may be done conveniently. The excess, when any, runs back 
to the river. Irrigation is stopped about a week before cutting, 
one crop being cut per year. In 1891 the total water applied from 
July 3 to the close of the season, was 100 acre-feet, from which we 
may deduct at least 6 acre-feet for the other crops, which do not re¬ 
quire as much as the meadow, taking the other measures in the 
valley as the basis. This would leave 92 acre-feet applied to 32 
acres of meadow, or a depth of 2.9 feet. 
In 1892 the quantity used was not so great as in 1891, the total 
quantity from May 25 to the time of cutting being 81.4 acre-feet. 
Six acre-feet of this may be considered as having been applied to the 
six acres of other crops, leaving 75 acre-feet for the 32 acres of 
meadow, or a depth of 2.4 feet. 
This shows a larger use of water than the cereals and alfalfa, 
and thus a smaller duty, as is well known, but the quantity used is 
much less than was anticipated. In European meadows waterings- 
are given at short intervals, and it is expected to cover them to 
much greater depths. The most careful measurements on the water 
applied to meadows have been made by Mangon on those in South¬ 
ern France and in the Vosges. Sometimes the amount applied is 
sufficient to cover the field to a depth of 1,400 feet (448 metres), 
measuring the gross amount applied, as in this case, and the net 
amount absorbed is equivalent to over 160 feet. (Mangon Experi¬ 
ences sur TEmploi des Eaux dans Irrigation, p. 46, 153, table 12.) 
