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The meteorology of Philadelphia
423
METEOROLOGY. For the Journnl of the Franklin Institute.
The Meteorology
of Philadebhia.
By JAMES A. KIRKPATRICK,A.M.
mean temperature of April, 1862, was about 34’ APRIL .-The below that of the same month of 1861, and la0 below the average temperature of the month for eleven years. The warmest day of the month was the 18th, of which the mean tem(82”) being reached on perature was 70°, the maximum temperature the same day. The coldest day was the 9th, with a mean temperature of 33*2O. The minimum (28O) was attained on the same day. The pge of temperature for the month was 54O. The temperature was below the freeaing point on but 3 da,ys of the malath, namely, the 8th, 9th, and 10th. The greatest change of temperature in the course of one day was 2’7Oon the 17th day of the month ; the least was 7” on the 21st. The overage daily oscillation of temperature (17%“) was a little more than one degree less than that of April, 1861, and about one degree more than the average for eleven years. The greatest mean daily range of temperature (that is, the greatest average difference of temperature between one day and that immediately following or preceding it),, was 14’, between the 18th and 19th of the month; the least was l-8’, between the 26th and 27th. The averqe daily range for the month (539”) was almost identical with that for April, 1861, and was about half a degree below the average for eleven years. The pressure of the atmosphere was greatest (30.321 inches) on the morning of the 16th of the month ; and least (29.422 ins.) on the afternoon of the 2U. The greatest daily mean pressure (30.300 inches) occurred on the l&h, and the least (29.439 inches) on the 22d. The average pressure for the month (29,999 inches) was 0.183 of an inch greater than for April, 1861, and O-194 of au inch greater than the general average for eleven years. The greatest mean daily range of atmospheric pressure was O-3 of an inch, and occurred between the 21st and 221~ days of the month; the bast was W44 of an inch, between the 26th a,nd 27th. The average mean daily range for the tnonth (O-146 in.) was O-025 of an inch less than the average for April for eleven years. The force of va,por was less than usual. It was greatest (0*X& in.) on the l&h, and least (0.091 in.) on the 7th of the month. The avec rage for the month (0.219 in.) was about two-hundredths of an inch less than the general average. The relative humidity was greater than for April, 1861, but less than the average for eleven years. It was greatest (94 per cent.,) on the morning of the 9th of the month, during a snow storm, and least 18 per cent.) on the afternoon of the 27th. The avera.ge humidity at
Meteorology
424
of Philadelphia.-April.
for the month was about 2 per cent. more than for April, 1861, and 3 per cent. less than the general average for eleven years. Rain or snow fell.on eleven days of the month, to the aggregate depth of 3.947 inches, which is one-fifth of an inch less than fell in April, 1861, and nearly one inch less than the average amount for eleven years. There were three days of the month, the llth, 12th, and 27th, entirely clear or free from clouds at the hours of observation, and the sky was completely covered with clouds at those hours on five days. The average amount of the sky covered with clouds during the month of April, 1862, was about 62 per cent.; during April, 1861, it was 53 per cent., and the average amount for eleven years is 60 per cent. of the hemisphere. A snow storm commenced about 9 A. M. on the 8th, and continued until 8 A. M. on the 9th, when there was about three inches,of snow on the ground. It commenced again about half past 2 on the afternoon of the Yth, and continued until ti) A. M. of the lOth, when the snow had attained the depth of about 12 inches. This was the last snow of the season. A Comparison of Some of the Meteorological Phenomena of APRIL. 1862, with those of APRIL, 1861. alad of the same month fo7 ELLVBN years, at Philadelphia, Latitude 39O 573’ N.; Longitude 75“ 104 W. from Greenwich.
Pa.
April, 1862.
April, 1861.
April, 11 Years.
820
88’= 20 16.89 6.40 45.63 57.5 1 49.46 50.86
--_-----l’hermometer.-Highest, . . “ Lowest, . * . “ Mean daily oscillation, ‘L daily range, . “ Mks at 7 A. M “ “ 2P.M.: . I‘ “ 9 P. M., “ “ for the 1Month,
28.0 17.87 5.89 44.57 55.23 48.28 49.36
8B’= 33 19*05 5*85 47.18 60.55 51.10 52.94
Barometer.-Highest, . . . 6‘ Lowest, . . . ‘1 . Mean daily range, .‘ . Means at 7 A. M., “ “ 2 P. M.. “ “ 9 I’. M., . * “ “ for the Month,
30.32 I in.i 29422 .146 1 30.025 / 29*9,9 j 29994 , 29.999
30.233 I”. 29.213 -143 29+345 29787 29.816 ! 29.816
30 518 in. 28,884 a173 29,824 29.752 29.YOS 29.805
-231 in.1 -226 -2.59 -238
-233 in. *247 ~2.50 -243
Force of Vapor.-Means ‘. ‘I 1‘ “ 6‘ “ “ “ “ Relative 1‘ ‘I “
at 7 A. M., 2 P. nf., 9 P. M., for the ‘Month,
Humidity.-Means at ; $. E., ‘4 “ “ ‘I 9 P: M:: “ u for the Month,
. Rain and melted snow, amount No. of days on which rain or snow fell, Prevailing
winds-Times
in lOOO-ths,
--
*211 in -219 ~228 *219 6p8 per ct. 48.5 64.5 60.3 3.947 in. 11
66.9 per ct. 42.3 65.3 59.2
71.8 per ct. 51.3 67.5 63.5
4.150 in. 9
N.45’0’ E. *047,N.73°30’~177,N.6805/
4.799 in 12.8 w.*16
I
METEOROLOGY. For the Journnl of the Franklin Institute.
The Meteorology
of Philadebhia.
By JAMES A. KIRKPATRICK,A.M.
mean temperature of April, 1862, was about 34’ APRIL .-The below that of the same month of 1861, and la0 below the average temperature of the month for eleven years. The warmest day of the month was the 18th, of which the mean tem(82”) being reached on perature was 70°, the maximum temperature the same day. The coldest day was the 9th, with a mean temperature of 33*2O. The minimum (28O) was attained on the same day. The pge of temperature for the month was 54O. The temperature was below the freeaing point on but 3 da,ys of the malath, namely, the 8th, 9th, and 10th. The greatest change of temperature in the course of one day was 2’7Oon the 17th day of the month ; the least was 7” on the 21st. The overage daily oscillation of temperature (17%“) was a little more than one degree less than that of April, 1861, and about one degree more than the average for eleven years. The greatest mean daily range of temperature (that is, the greatest average difference of temperature between one day and that immediately following or preceding it),, was 14’, between the 18th and 19th of the month; the least was l-8’, between the 26th and 27th. The averqe daily range for the month (539”) was almost identical with that for April, 1861, and was about half a degree below the average for eleven years. The pressure of the atmosphere was greatest (30.321 inches) on the morning of the 16th of the month ; and least (29.422 ins.) on the afternoon of the 2U. The greatest daily mean pressure (30.300 inches) occurred on the l&h, and the least (29.439 inches) on the 22d. The average pressure for the month (29,999 inches) was 0.183 of an inch greater than for April, 1861, and O-194 of au inch greater than the general average for eleven years. The greatest mean daily range of atmospheric pressure was O-3 of an inch, and occurred between the 21st and 221~ days of the month; the bast was W44 of an inch, between the 26th a,nd 27th. The average mean daily range for the tnonth (O-146 in.) was O-025 of an inch less than the average for April for eleven years. The force of va,por was less than usual. It was greatest (0*X& in.) on the l&h, and least (0.091 in.) on the 7th of the month. The avec rage for the month (0.219 in.) was about two-hundredths of an inch less than the general average. The relative humidity was greater than for April, 1861, but less than the average for eleven years. It was greatest (94 per cent.,) on the morning of the 9th of the month, during a snow storm, and least 18 per cent.) on the afternoon of the 27th. The avera.ge humidity at
Meteorology
424
of Philadelphia.-April.
for the month was about 2 per cent. more than for April, 1861, and 3 per cent. less than the general average for eleven years. Rain or snow fell.on eleven days of the month, to the aggregate depth of 3.947 inches, which is one-fifth of an inch less than fell in April, 1861, and nearly one inch less than the average amount for eleven years. There were three days of the month, the llth, 12th, and 27th, entirely clear or free from clouds at the hours of observation, and the sky was completely covered with clouds at those hours on five days. The average amount of the sky covered with clouds during the month of April, 1862, was about 62 per cent.; during April, 1861, it was 53 per cent., and the average amount for eleven years is 60 per cent. of the hemisphere. A snow storm commenced about 9 A. M. on the 8th, and continued until 8 A. M. on the 9th, when there was about three inches,of snow on the ground. It commenced again about half past 2 on the afternoon of the Yth, and continued until ti) A. M. of the lOth, when the snow had attained the depth of about 12 inches. This was the last snow of the season. A Comparison of Some of the Meteorological Phenomena of APRIL. 1862, with those of APRIL, 1861. alad of the same month fo7 ELLVBN years, at Philadelphia, Latitude 39O 573’ N.; Longitude 75“ 104 W. from Greenwich.
Pa.
April, 1862.
April, 1861.
April, 11 Years.
820
88’= 20 16.89 6.40 45.63 57.5 1 49.46 50.86
--_-----l’hermometer.-Highest, . . “ Lowest, . * . “ Mean daily oscillation, ‘L daily range, . “ Mks at 7 A. M “ “ 2P.M.: . I‘ “ 9 P. M., “ “ for the 1Month,
28.0 17.87 5.89 44.57 55.23 48.28 49.36
8B’= 33 19*05 5*85 47.18 60.55 51.10 52.94
Barometer.-Highest, . . . 6‘ Lowest, . . . ‘1 . Mean daily range, .‘ . Means at 7 A. M., “ “ 2 P. M.. “ “ 9 I’. M., . * “ “ for the Month,
30.32 I in.i 29422 .146 1 30.025 / 29*9,9 j 29994 , 29.999
30.233 I”. 29.213 -143 29+345 29787 29.816 ! 29.816
30 518 in. 28,884 a173 29,824 29.752 29.YOS 29.805
-231 in.1 -226 -2.59 -238
-233 in. *247 ~2.50 -243
Force of Vapor.-Means ‘. ‘I 1‘ “ 6‘ “ “ “ “ Relative 1‘ ‘I “
at 7 A. M., 2 P. nf., 9 P. M., for the ‘Month,
Humidity.-Means at ; $. E., ‘4 “ “ ‘I 9 P: M:: “ u for the Month,
. Rain and melted snow, amount No. of days on which rain or snow fell, Prevailing
winds-Times
in lOOO-ths,
--
*211 in -219 ~228 *219 6p8 per ct. 48.5 64.5 60.3 3.947 in. 11
66.9 per ct. 42.3 65.3 59.2
71.8 per ct. 51.3 67.5 63.5
4.150 in. 9
N.45’0’ E. *047,N.73°30’~177,N.6805/
4.799 in 12.8 w.*16
I