RUSSELL.] WELLS. 171 
termed accidental fissures. A fissure spring- may, however, be due to 
the leakage of either an artesian basin or an artesian slope, and is at 
least a sure indication that water in a subterranean reservoir of some 
kind exists under sufficient pressure to force it to the surface. In an 
arid region every such indication should be tested in case the water 
can be utilized. 
Three miles north of Mountain Home, and at an elevation of about 
110 feet above the town, there is a spring known as Bennett Spring, 
near which a drill hole 6 inches in diameter has been put down to a 
depth of 50 feet, all in basalt. The casing of this well is defective and 
water rises both within and around it, as well as from natural openings 
near at hand. At the time of my visit, August 2, 1901, this imper- 
fectly developed spring was discharging about one-half cubic foot per 
second. The temperature of the water was 55° F. From the assumed 
temperature gradient given above the depth from which the water rises 
is judged to be about 225 feet. The water is not only cool, but, so far 
as one can judge by tasting, is of excellent quality. Mr. Bennett, the 
owner of the well, informed me that it flows continuously, but that the 
supply decreases in summer; other persons have stated that it some- 
times becomes dry, and expressed the belief that it is fed by seepage 
from the Mountain Home reservoir or its feeding canal. In reference 
to this last statement, I would say that the natural conditions indicate 
that an escape of water has occurred for many years, and that most 
probably the spring is due to a weak discharge of water from a shal- 
low fissure. 
On account of the favorable location of the Bennett Spring, the excel- 
lence of its water, etc., it is highly desirable that an effort be made to 
increase the, flow. The present drill hole should be tested in order to 
learn how much water it will deliver when all leakage is stopped, and 
then deepened to at least 225 feet. By suitable tests the most favor- 
able water-bearing horizon could then be determined, and, if desir- 
able, the rocks at that horizon should be shattered by an explosion of 
dynamite. With the information thus gained, if favorable, several 
other holes should be drilled within a radius of 200 feet of the present 
well. It is not improbable that this spring can be made to yield suffi- 
cient water for the present needs of Mountain Home. 
WELLS. 
For convenience, we may classify wells as, first, surface or earth 
wells, deriving their water by percolation from the surface sheet of 
rock waste, usually shallow and represented by the ordinary house 
wells of humid regions; second, rock wells, usually deep, penetrating 
the unaltered rocks beneath the surface sheet of rock waste, if any is 
present, and obtaining from pervious strata water which may be under 
some pressure, but which does not rise to the surface; and third, arte- 
sian wells, from which there is a surface overflow. 
