260 MONTHLY WEATHER REVIEW. JUNE, 1904
In his twenty-five years of service he had been on duty on
nearly twenty different stations, scattered from coast to coast
and from arctic seas to the Gulf of Mexico. His labors from
1883 to 1886 a t St. Micheals, Alaska, the farthest north of the
weather stations, were particularly appreciated and valued.
He was a polished gentleman, genial, cheerful, and gen-
erous, and easily won his way in the esteem of the communi-
ties to which the service called him. He was industrious and
efficient, and was frequently commended for the accuracy of
his meteorological work.
~~
EARTHQUAKES OF JUNE 25 AND 26,1904.
By Prof. c‘. F. MARVIN.
The seismograph at the Weather Bureau recorded an earth-
quake on June 25, beginning at 4 hours, 12 minutes, 31 seconds,
p. m., and another on June 26, beginning at 7 hours, 21 min-
utes, 3 seconds, p. m. The reoorcl in both cases inclicat,ecl a
very slight displacement of the earth a t Washington, but the
character of the records is such that we believe the origins
were at very great distances ancl seemingly nearly t,he same
for both earthquakes. The disturbances of themselves were
probably of considerable violence.
I n the record of the first earthquake, especially, the ampli-
tude of the movement at Washington was very small, nncl es-
act measurements of the record can not be made The differ-
ent phases ordinarily dmracteristic of earthquake reclords
from instruments of this class are more clearly defined in the
second than in the first earthquake.
The Omori seismograph, by which these rec,ords were macle,
was fully described and illustrated in the MONTHLY WEATHER
REVIEW for June, 1903, page 271.
The following table gives the times of the principal features
of both records. The north ancl south component of horizon-
tal motion only is recorded.
Earfhqtmkes of Ju.7~ 2.5 mnd 26, f9lLj, p . m ., 8erenty;fifth nferii7iuii. time.
Juue 25. June 3;.
h. in. s. h. ?)I . 8.
First preliininary tremors. 4 12 31p.111. 7 21 03 p.m.
Principal portion began.. ............ 4 44 59 p. m. 7 55 26 p. in.
Principal portion ended. ............. 4 55 46 p. IU. 7 57 01 11. ni.
Masimuni waves at
End of earthqucLke.. ................. 5 29 04p. ~n . 8 25 CIO p.m.
Average period of complete waves in
Maximum clonl.~le amplitude of avtual tlisplaccnicnt of
earth at seismograph ............................ Magnificat,ion of record ............................... 10
STUDIES ON THE CIRCULATION OF THE ATMOSPHERES OF THE SUN AND OF THE EARTH.
VI1.-THE AVERAGE MONTHLY VECTORS OF THE GENERAL CIRCULATION IN THE UNITED STATES.
Secniitl preliiiiiiiary trenior __ --p. 111. 7 46 5R p.m.
.................. \ 4 50 3t;p. In. I t5 5,; lll.
1 4 53 2ip.111. (
Duration of first preliminary tremor. . 33 28 34 23
principal portion ................ 20 20
Periocl of pendulum 2G 26 .................
0.26 UIU.
By Prof. FRANK H. BlGEL4JW.
I n Table 9, page 144, Annual Report of the Chief of the
Weather Bureau, 1898-1899, may be found the data result,iiip
from the nephoscope observations taken in the international
cloud year, 1896-1897, which were made to determine the g8n-
era1 motions of the atmosphere over the United States. I n
Table 33, page 403, of the same volume, is given a mininary
of the resulting general velocities as annual norm&. It re-
mains to compute the mean monthly normal vectors of t,he
circulation, and it ha.8 been clone by the methods used in com-
puting similar veckors for the West Inclies, so thst but few
preliminary remarks are needed in this connection. Tho
method now in use in the Weather Bureau of determining the
monthly direction of the wind at a station is really inadequate
to the requirements of modern science, which demands an ac-
curate knowledge of the azimuth direction ancl velocity of the
wind. The method referred to consists in counting the num-
ber of times the wind was reported on each of the eight car-
dinal points, N., NE., E., etc., and assigning as the monthly
direction that which has the plurality of numbers. This gives
no true resultant direction and takes no account of the veloc-
ity of the wind prevailing at each observation. A second
method of reducing wind observations, which is somewhat
more accurate than the former, consists in assuming an equal
velocity for each wind and combining the frequency numbers
by using Lambert‘s formula or its equivalent. This system
gives a true resultant direction for winds of uniform velocity,
but where the winds are variable in force, as well as in direc-
tion, this is also insufficient. Many examples of inaccurate
resultants can he given when the individual velocities are not
constantly the same.
The vectors of Table 16, and figs. 77 to 68, Charts S I , SII,
and S I I I , **Average monthly vectors of the general circulation,”
have been computed accurately by resolving each vector T’, y,
as observed, into its north to south and west to east components,
taking the algebraic sum of each, and thence computing the
mean component for the series, in this case for each month of
the year. Then the resultant vectors in velocity and azimuth
were constructed, and appear in Table 16 under the columns
T; q. Since the resultant rectors in the lower cloud level and
at the surface are very small. I have also computed the mean
motion of the nind for each month without regard to the
aziiiiuth direction, and this is given under P:. In the middle
ancl the upper cloud strata the azimuth directions are not so
variable as nearer the surface, and hence, there is less differ-
ence between the values of T-, and 1: The resultant vectors
1: +n have been plotted in two arrangements, the first giving
the vectors of the month for each cloud systeni terminating
on the same vertical lines, which periiiits a ready inspection of
the relative motion in the dif-l’erent levels for each month of
the year. The second arrangement gives the vectors for June
encling on one vertical line, while those for the other months
follow in a broken line, nhich shows at a glance the trend of
the circulation throughout the year in the several cloud
groups. It has been convenient to. divide the clouds into
three groups, (1 ) the lower clouds (stratus, cumulus, strato-
CULUU~US), (3) the middle clouds (alto-stratus, alto-cumulus),
ancl (3) the upper cloucls (cirro-cumulus, cirro-stratus, cirrus),
which 110 not differ greatly among themselves in velocity.
The average height of group (l), lower clouds, is 2000 meters;
of group (a ), middle clouds, 5000 meters, and of group (3),
upper clouds, 9000 meters, as determined by the theodolite
observations at WaVn.Jhington, in 1696-1697.
We make the following remarks on the vectors of Charts SI
to 1111. The northern group of stationR, St. Paul, Detroit,
Cleveland, Buffalo, Loui,sville, Blue Hill, Washington, Waynes-
ville, and Ocean City, a11 lie in the strong eastward drift to
the north of the high pressure belt of the general circulation;
Iimisas City, Abilene, ancl Vicksburg, lie in the midst of this
belt, while Iiey West is on the southern border of i t and has
some of the characteristics of the West Indian group of sta-
tions. The northern stations in the upper levels have strong
eastward components, and in the lower levels a turbulent cir-
culation with small resultant vectors. Louisville seems to
have something like a personal ecluation, which has magnified
the vectors a little above the apparent average that the en-
tire set won1;L suggest, while Cleveland, on the other hand,
seems to have a diininished set of vectors. It is not pomible
to show from the observations what change, if any, ought to
be introduced by means of a moclifying factor. Besides the
relative lengths of the vectors in the different levels it is in-
teresting to note the north and sonth components at the sev-
eral stations. Thus, at St. Paul and also at Kansas City, there
is a northward component in the cirrus levels; this component
prevails at all levels at Abilene. At Vicksburg the vectors are
generally small, and they are westward during certain months