224 National Geographic Magazine. 
In considering the duty of a stream it must be remembered 
that there is a great loss of water by seepage through the sides of 
a canal and evaporation from its surface, between the headworks 
and the irrigated lands, this loss may amount to from 25 to 35 
per cent., according to climate, soil, and the length and cross- 
section of the canal. 
PRESENT STATE OF [RRIGATION—PROGRESS AND LAWS. 
The earlier stages of irrigation development are better illus- 
trated in Montana than in any other State in the Union. 
There irrigation practice and laws are exceedingly crude and 
remain so chiefly because of the abundance of water, and the ease 
and facility with which it can be diverted to the land ; as a con- 
sequence of this latter fact the laws were framed in the most 
liberal spirit, declaring right of eminent domain, acknowledging 
the right of priority in appropriating the waters, and further 
stating, that any person having a ditch leading to irrigable lands 
may use the waters of the territory for irrigation. 
The latest law, framed in 1885, is a very slight improvement ; 
it requires persons appropriating water, to post the usual notice in 
a conspicuous place ; to file with the county recorder a notice of 
appropriation, with names and proper description of place, 
stream, etc., and that work. must be commenced within forty 
days of the posting of the notice and be prosecuted with due 
diligence until completed. 
Persons who have heretofore acquired title to the use of water, 
may within six months from the passage of this law file a state- 
ment of the above facts in the office of the recorder, but failure 
to do this shall not forfeit his rights. 
Provision is made for the measurement of water, using that 
very uncertain and elastic unit, the miner’s inch, and defining the 
same. 
The difficulties arising under these laws will be appreciated, 
when I state that it is impossible to construct a rating flume that 
will measure the number of inches of water flowing in a large 
stream, by the method provided in the law. 
Then, because previous appropriators are not compelled to 
record the amount of water appropriated, and those acquiring titles 
under the first law now invariably claim much more water than 
they need, in fact often appropriate and even record more water 
than there is flowing in the stream. This is owing to the fact that 
