SEPTEMBER, 1899. MONTHLY WEATHER REVIEW. 409
possibilities of the case, as near as I can compute them, arc
as follows, taking the flood of 1897 as the maximum condi.
tion, and the danger line of 45 feet a t Vicksburg as the lint
above which the water would begin to run off into the canal
At the tinie of the maximuni stage of 59.3 feet the dischargc
in cubic feet per second was about l,tiOO,OOO, while a t thc
45-fOOt stage it was about 1,300,ONI. The difierence of 3100,OOC
feet is the quantity which it is desired to dispose of through
the proposed canal. Assuming the velocity of the currenl
to be 4 miles per hour, which is equivalent to 5.87 feet pel
second, tho. cross section of the canal would have to bE
300,000 + 5.87 = 51,107 square feet. Therefore, i f the depth
were to be 30 feet, the width would have to l e 51,107 + 30 =
1,703.6 feet, and its length would be ahout 13 miles. Both
banks would need protection by revetments to secure per-
manency. I cau give 110 close eetimate of the cost of such a
work, but I think i t could be done for $20,000,000 or less
On paper i t certainly' appears feasible. Opponents of the
canal argue that it would gradually fill up by deposits of
sand, but this objection is met by the reply that i t applieg
equally to any portion of the river, and the canal, owing tc its comparatively limited extent, could be effectually dredged
to the required depth whenever necessary.
Above the mouth of the Missouri attempt has been made t a
lessen the flood .heights by building storage reservoirs at the
head waters. Five of these reservoirs were built, with a view to store surplus waters, which should be available for purposee
of navigation when the low-water season set in. These antici-
pations were not realized, however. The floods were repressed
to some extent a8 far as Lake Pepin, but not below, and ae
much as 1 foot of additional water was available at the low-
water season at St. Paul, disappeariug by the time Redwing,
Minn., 58 miles below, was reached. In any event, with or
without reservoirs, no floods north of Lake Pepin are felt to
the southward to any considerahle extent.
The effect in the lower river of an all levee system upon
navigation would be to narrow the chamiel and, consequeutly,
increase the velocity of flow during high water, thereby retard-
ing somewhat the upstream movement of boats. Relief would
come quicker, however, owing to the greater velocity of the
water, as it would, of course, run off sooner. I n times of low water it is probable that, there being no overflow or back
water to run into the main stream and the levees causiug a
greater velocity in the flow of the water already there, the
low-water season would be prolonged and still lower stages
prevail than had obtained in the past. This would be impos-
sible with the storage reservoir, as the surplus water could be
let into the river just as needed.
This completes about all I have to say upon this subject,
and I beg of you to bear in mind that I do not come here as
an expert in these matters: I simply present to you the facts
as I have gathered them in various ways. The subject is cer- tainly one of deepest importance, and justifies almost any
expenditure of time and money to produce satisfactory re-
sults. The proper improvement of the Mississippi River may require thirty or forty years of time and may cost $300,000,000.
It could probably be done in one-half the time and for one-
half the money or less. But no matter what the cost, the moral, social, and economic development of many millions
of people is directly concerned, and it is not always wise to
too closely reckon the cost in mere dollars and cents.
SMALL WHIRLING COLUMNS OF MIST.
By RALPE B. MAREAN. Weather Bureau, dated October 5%. 1899.
On Sunday, October 23, n very interesting meteorological
phenomenon was observed by me at the upper or receiving
reservoir on the Conduit road a few miles above Washington.
It was about 7:30 of a perfectly clear, calm, frosty morning.
Over the mirror-like surface of the pond hung a ragged mist
from 5 to 10 feet deep and so thin that i t did not obscure
objects on the opposite shore, some three huudred yards dis-
tant. When first seen there was no perceptible niovenient
in this veil of mist; i t rested almost motionless on the sur-
face of the lake. Soon, however, it \.vas noticed that i t had
begun to drift hither and thither in all directions. I n two places within 50 or 100 feet of each other the movement
would be in opposite directions. Almost simultaneously
with the beginniug of this movement of the fog there ap-
peared whirls or spouts in the mist, seeming to form where
two nearly opposite currents of air met, as shown by the
drifting mist. Some of the columns were evidently formed
as rolls between two parallel opposed currents. When first formed these spouts were from 2 to 4 feet in diameter, ex-
tending but 2 or 3 feet above the surface of the water and
rotated (counter clockwise) hut five or six times per minute.
The speed of rotation rapidly increased, however, until a t
the end of half a minute or so i t would be about thirty or
forty per minute, the diameter decreasing a t the same tinie
to from 6 to 18 inches, while the column grew until about
20 feet in height. The column appeared hollow, the denser
miet being in the outer ring. I n the fully developed whirls
there was a well defined upward spiral motion, the augle of
ascent being, as nearly as could be judged, between 45O and
GOo with the horizontal. Slthough some of these spouts
lasted probably as long as five or six minutes, their average
life was abont two minutes, but within the twenty or twenty-
five minutes during which the phenomenon was observed a
great many, probably over a hundred, of these little whirling
columns of mist were seen.' Generally they had no progres-
sive motion, although a few wandered aimlessly here and
there. Gradually the number of the spouts diminished and
finally in about half an hour no more were formed, the mist
in the mean time having become almost entirely dissipated,
partly by the risiug sun and partly by the mixture of dry air.
Of course one.could not witness a phenomenon of this kiud
without trying to discover its cause. It seems to the writer
that the lower strat.um of air had become heated by radiation
from the comparatively warm water, but as uo disturbing inci-
dent occurred it lay in the hollow over the lake in a state of
iiustable equilibrium. As soon as something happened, how-
ever, to disturb this equilibrium the cold overlying air began
to fall and crowded up the warm, light stratum beneath.
The scenewas one of great beaut-y. I n the eight or ten
Bcres of the lake in view there would be a great number of
these miuature colunins of mist standing in relief against the
dark pines in the background and as erect as they.
ADDITIONAL OBSERVATIONS OF THE ST. KITTS, W. I., HURRICANE.'
By W. H. ALEXANDER, Observer.
About noon of Thursday, September 7, the wind changed
From the northeast to the north, from which direction i t blew
iteadily with an average velocity of 17 miles per hour until
2 a. m. of the Sth, when i t began varying between north aud
northwest and increasing in force. About 5 a. m. it set in
gteadily from the northwest and continued from that direc-
tion until 1 p. m., when it began shifting to the west aud
increasing rapidly in force. From 1:15 to 3:40 p. m. the wind
:ame from the west with an average velocity of about 36
miles per hour. At 3:40 p. m. it shifted to the southwest
md soon reached verifying velocity. About 3:15 n. ni. of
the 9th, the wind began l~lowiug from the south, and by noon
t was criiiiitig ptertdily frnm thnt direct.ion.
'From a second report hy Mr. Alexander, we copy the folloairig tdditiorial details, received too late to be iiiserted in the chapter on Forecasts and Warnings.
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