COLORADO IRRIGATION WATERS AND THEIR CHANGES. 17 
quantity brought in by the springs could be detected with ease in 
the quantities of water actually used. Again, the presence of 
strontia is demonstrable with comparative ease in both the ground 
waters and the river waters. These facts were difficult to explain, 
and puzzled me greatly, leading me to doubt the correctness of my 
observations until frequent repetitions established it as a fact. The 
presence of these in the felspar and the power of even slightly car¬ 
bonated water to take them into solution accounts fully and satis¬ 
factorily for their general presence in the river and ground waters, 
and enables 11s to trace the source from which the water obtains its 
original content of mineral matter. It further makes it very prob¬ 
able that all the waters flowing out of the area presenting the same 
general conditions, whether they flow eastward, as in case of our 
* streams, or westward, as in the case of the streams of the western 
slope, have the same general properties until changed by new 
conditions. 
CHANGES SUFFERED WHITE FLOWING IN BED OF STREAM. 
§ 30. The analyses of the Poudre water already given show 
clearly that such changes take place before the waters have com¬ 
pleted any considerable portion of their course. The sample 
taken above the mouth of the North Fork, Nov. 3, 1902, Table II, 
was taken at a time when there was no flood water and after a 
period of good weather. The snows of the preceding season had 
either disappeared, or were melting so slowly as to have little or no 
influence upon the flow, so that the water then flowing represented 
the normal water of the Poudre as nearly as we could obtain it. 
The samples taken from a tap in the Chemical Laboratory, 
especially the samples represented by analyses five and six, both 
taken in the month of September, one in 1900, the other in 1902, 
represent the same water after it had flowed for a distance of about 
eight miles to the water works, where it passed into the city 
mains. 
§ 31. The principal difference that we observe is that the 
amount of total solids has increased from less than three grains 
(2.9 grains), to 7.4 grains in the first instance, and, 10.2 in the 
second, that is, from two and one-half to three and one-third times 
the original amount. 
§ 32. The water taken in the first sample had probably 
flowed sixty miles over the bed of the stream, but it had received 
water of its own kind, coming, as it had, through granitic sands 
and rocks. The last two samples had flowed only ‘ eight miles 
further, and only a portion of this distance was over a bed of a dif¬ 
ferent character; and yet in a distance of less than 1 eight miles the 
amount of mineral matter held in solution has been .increased by 
these multiples. The greatest changes, however, have liot been 
