352 
Bavarian foreland ; and that as the sea with- 
drew the Danube was developed along its 
trough, engrafting into its trunk the many 
smaller streams that before had independent 
courses. As the valleys of the consequent 
streams were deepened, trenches were cut 
through the resistant strata of the white Jura, 
whose retreating margin was in time worn back 
(southeast) to form a cuesta with an infacing 
escarpment, while an inner lowland was opened 
on the weak Lias beds between the escarpment 
and the crystallines of the Black forest. To-day 
only one of the consequents (Brege-Danube) re 
tains its course through the cuesta. The 
Wutach has been diverted from the Aitrach to 
the Rhine ; the Brigach has been captured from 
the Elta by the Danube itself; and the Neckar 
has taken the Eschach from the Faulenbach. 
Similar changes are known for a long distance 
northeast of the Eschach, where the phenomena 
associated with the drainage of cuestas are illus- 
trated in great variety. Penck uses the terms 
Folgefluss, Schichtfluss and Gegenfluss for conse- 
quent, subsequent and obsequent streams. 
W. M. Davis. 
CURRENT NOTES ON METEOROLOGY. 
A NOTABLE STUDY OF ECLIPSE METEOROLOGY. 
In his paper on ‘ The Eclipse Cyclone and the 
Diurnal Cyclone’ (Proc. Amer. Acad. Arts and 
Sci., XXXVI., Jan., 1901, 307-318) Clayton 
has gone far ahead of all previous investiga- 
tors of the phenomena of eclipse meteorology. 
Hitherto, as a general rule, we have had little 
more than a few scattered observations of tem- 
perature, pressure, wind direction, etc., taken 
during an eclipse, and tabulated, with a brief 
summary of the results. In his study of the 
meteorological data obtained in connection with 
the total solar eclipse of May 28th last, Clayton 
has derived results of far-reaching importance, 
which throw light on two of the largest problems 
in meteorology. 
The meteorological changes due to the eclipse 
were first separated from other changes, such as 
the diurnal and the cyclonic, and were then 
plotted on maps of the United States for 8.15 
and for 9 A.M., May 28th, 75th meridian time. 
These maps show that the winds were prac- 
tically reversed in direction as the umbra 
SCIENCE. . 
[N. 8. Von. XIII. No. 322. 
moved from one side of the continent to the 
other, both maps showing a distinct anticyclonic 
circulation and an outflow of air extending from 
the umbra to a distance of about 1,500 or 2,000 
miles. The temperature depression due to the 
eclipse appears on the 9 A.M. chart as an oval 
area. At the central portion of this area the 
depression exceeds 8° Fahr., and this area of 
greatest cold lags behind the umbra about 500 
miles. A third chart was constructed by plot- 
ting the stations at their proper distances from 
the path of the umbra, and plotting the succes- 
sive 15-minute observations at intervals of about 
500 miles, the result being a synoptic chart 
showing the conditions observed at any station 
or group of stations when they were in different 
portions of the eclipse area, This synoptic chart 
indicates distinctly an anticyclonic circulation 
of the wind around the center of the eclipse, ex- 
tending out to a distance of about 1,500 miles 
from the umbra. Beyond this there are indi- 
cations of another ring of outflowing winds. 
The isotherms show an elliptical area of cold 
air (inner isotherm 6° Fahr.) central about 500 
miles in the rear of the umbra. There was a 
rise of absolute and of relative humidity during 
the eclipse, the shape and position of the areas 
showing the humidity departures being very 
similar to those of the temperature. The pres- 
sure changes in this eclipse, and in other eclipses, 
show that in normal eclipses there is a central 
area of relatively high pressure; surrounding 
this a ring of minimum pressure, and beyond 
this, outside the edge of the penumbra, is a ring 
of maximum pressure. 
The low temperature, the circulation of 
winds and the form of the pressure curve, all 
proclaim the development by the eclipse of a 
cold air cyclone, as described by Ferrel. Mr. 
Clayton points out that the eclipse may be com- 
pared with an experiment by Nature in which 
all the causes that complicate the origin of the 
ordinary cyclone are eliminated, except that of 
a direct and rapid change of temperature. The 
result shows that a fall of temperature is capable 
of developing a cold-air cyclone in an astonish- 
ingly short time, with all the peculiar circulation 
of winds and distribution of pressure which 
constitute such a cyclone. The fall of tem- 
perature acts primarily to cause a cyclone, and 
