The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1869-09-06

WIN u lall tnrOugn space OF OSO leel, VIC Cttn
form an idea of the enormous force of which
the earth has been deprived during the forma-
ton of deltas produced by rivers flowing towards
the equator.
The matter composing the immense deltas of
the Ganges and the Mississippi, in order to ac-
quire an augmentation of crcumferential velo-
city corresponding with that of the outlets of
those rivers, has demanded an expenditure OF
force so vast-a force which the earth has sup
pned-that astronomers might look in that di-
rection for an explanation of some of the re-
tardation which the lunar tables reveal. Un-
questionably the Mississippi, Ganges. and Indus
alone transfer sufficient quantity of matter in
the direction of the equator, and thereby con-
tinually eXtnguish so great an amount of the
earth's Uis 0jUd that, unless it can be proved
that the loss thus sustained is counterbalanced
by the operation of the general river system of
the globe, q retarding force must be admitted to
exist sufficient to diminish sensibly the rotary
velocity of our planet in the course of ages.
THE MISSISSIPPI BASIN.
The question whether such proof can be
furnished, or the fact established that retarda-
ton actually takes place. is not by any means so
absurd as might at first appear. 1t is true we do
not know what quantity of water or sediment is
carried to the ocean by the several rivers; but
we can compute with sufficient precision the
extent OF the river basins. Accordingly, If we
could establish mean of discharge of some very
extensive basin, comprising all the variates of
climate and SOIL the question could be satsfac-
torily answered. Fortunately there is one river,
and that the longest on the globe, draining the
greatest extent of surface, with but one import
ant exception, which has been accurately, thor
oughly examined, viz, the Mississippi. Not
only has this great river been thus examined,
but 1t comprises every variety of soil and eli
mate, its source being among SHOWS and lakes
frozen during a great portion of the year,
while its outlet is near the tropics. How com
petely the Mississippi basin represents the
average of the river systems of both hemi-
spheres will be understood from this fact that
ot hDr q "
tremity show only thirteen inches for twelve
months, those of the southern extremity reach
siXty-six inches with every possible graduation
of rainfall in the intermediate space. In addi-
ton to this important circumstance, the basin
covers 21 deg. of latitude and 35 deg. of longi
tude, or 146O miles by 1870 miles; hence com
prising an area greater than the entire European
continent west of the rivers Vistula and Pruth.
1t may be confidently assumed, therefore, that
the Mississippi basin represents the average dis
charge of water and sediment so nearly that cal
culations based thereon, applied to the river
systems of both hemispheres, excepting some
of the Northern Asiatic and American rivers,
will exhibit a general result differing but
slightly from what would be established if all
the rivers had been examined.
propose to present. in another place, a synop-
sis of some points which bear directly on the
subject under consideration, contained in the
elaborate official reports on the Mississippi river
made by Humphreys and Abbott, 1861, which
report reflects so much credit on those officers
and the corps of Typographical engineers OF the
United States. Some calculations WILL however,
be submitted in this place, based on certain
facts established by the reports alluded to, in
order to give in advance distinct notion of the
amount of disturbing force which attends the
abrasion caused by the action of rain water in
its course to the ocean, over the Mississippi basin.
1t may be summarily stated that the calcula-
tons presented in the reports of General Hum
phreys and his able coadjutor, founded on obser-
vations continued during series of years. show
hot thn a1ntit nf ortln
ried into the Gulf of Mexico, partly suspended
in the water and partly pushed along the bottom
of the river by the current, amounts for each
twelve months to 903, 100, 900, 900 of pounds.
This enormous weight of matter is contributed
by numerous large branches and upwards of one
thousand small tributaries. The mean distance
along the streams III which the sediment is car
ried in its course towards the sea exceeds 1900
miles; but the true mean which determines the
amount OF force acting to check the earths rota-
tion is far less
The annexed maps of the Mississippi river
basin have enabled the writer to determine that
its centre is situated 20 deg 10 min west of the
mouth of the main river, and 10 deg Is min.
north of the same, in latitude 40 deg Is min.
The reader will find, on inspecting the section
of the earth represented on plate l6, that agree
able to the above determination the centre of
the Mississippi basin rotates in a circle of
l5 S4 1S2 feet radius and that its velocity round
the axis of the globe is l147'9O feet per second.
The mouth of the river on the other hand
rotates in a circle of 1926 1O2 feet radius with
a clrcumferential velocity of 1869 feet per
second. 1t will be seen, on comparing these
yelOctics, that an increased circumferential
velocity of nearly l19 feet per second must be
impaired to the sedimentary matter during it's
course from the centre of the basin to the mouth
OF the river
THE DRAG ON THE EARTH's ROTATION.
The question here presents itself where is the
motive energy to come from to impart the in
sod ,irn1 .
! We are compelled to answer by an admission
| that the earth must supply the needed force. In
| other words, an amount of the earth's UiS UiUd
| corresponding with the force required to gene
rate the augmented speed, will be eXtinguished.
| There Is, 9t course, no uncertainty about this
| proposition. Given the quantity of sediment
| discharged at the mouth of the river during a
! fixed period, or given the extent and depth OF
the delta OF the Mississippi and the specific
| gravity of its sedimentary matter we can state
with perfect accuracy the amount of retardatisr
! to he overcome by the earth every second, or the
| total amount OF ctS CtCG lost during the forma
tiOn of the delta.
1t has been already stated that the mean an
nual discharge of earthly matter at the mouth OF
the Mississippi Is 9O3, 100 millions of pounds
| The centre of the basin, indicated on the dia
! gram representing the earth, before alluded to
| being 2,46l $40 teet nearer the axis than tn
mouth oil the river, we can readily calculate thI
the increase of rotary velocity will be- as alread,
stated, l19 feet per second; rate acquired by
fall through 5006 feet The elements are thu
furnished for determining with precision tn
amount of 0ts cioG which the earth must par
with in consequence of the change of position q
matter attending the abrasion during the flo,
of the rain water from the basin to the mouth c
the river. Multiplying 903 100 millions nv hOOI
} we prove positively that the amount of energ
| to be given up by the earth in order to impal
G the stated incease of rotary velocity to th
e abraded matter, exceeds four hundred and fifty
0 | two trillons of foOt-pounds annually But In
| formation of 20 l(0 nilns of dol