istrict of Iowa,
to experience one of these triangular storms. We were at Dubuque while
the wind was blowing gently from the south-southwest, with low
scattering clouds, and before night it began to thicken and rain, while,
in the night, the wind shifted to the east, blowing the rain briskly
before it. This continued a part of the following forenoon, when, taking
the train west to Rockford, northwest of Dubuque, we reached nearly the
edge of the easterly storm, which had been here simply a drizzling rain.
The next day the rain had ceased, the wind had shifted to the northwest,
rapidly drying the earth, and the clouds, both of the upper and lower
strata, were all driving hurriedly east-southeast. We left the following
day for Fort Dodge and Sioux City. At the former place they had had a
slight shower only, with shifting winds; while at Sioux City not a
particle of rain had fallen, the roads being not only dry but quite
dusty. This was not a merely local storm, but was the only great
easterly one covering any extent of territory and time, answering to the
equinoctial, which visited the United States during last autumn.

This special limit of storms, this eddy of the winds in Iowa, deviates
more or less in the district assigned to it, and, at times, some of
these northeasters undoubtedly blow over Minnesota, but they are few,
and much modified in kind and character. The elevation of the State over
other portions of the great valley south of it adds something probably
in determining the outline of the Iowa basin of precipitation.

The range of the thermometer in the hot season is, in Minnesota, above
that of places occupying the same lines of latitude; this is caused, in
part, by the arid continental winds and by a less cloud-obstructed
sunshine, but the heat is not correspondingly oppressive with that of
other localities, since the atmosphere is not as humid. The evaporation
under this heat of summer rises out of the immediate region of the
surface, and is borne away on the prevailing winds to the lake district
and eastward. It is unfortunate that there have been no tests of a
hygrometic character maintained through any great period, whereby
reliable data could be adduced, since it would have seemed as easy for
the government to have undertaken that branch of meteorology as any
other, it only requiring a more careful and accurate hand than do the
other observations. The delicacy of these experiments have proved too
wearis