United States Weather Maps. 7 
eter at the latter place had not yet risen above 30 inches; and 
that in the few remaining cases there was at no great dis- 
tance from New Haven an area of relatively high barometer, 
althongh the actual height of the barometer did not much exceed 
80 inches. 
Lowest temperature for each month at New Haven, Conn., for the years 1872, 3, and 4. 
Ps al ooh Wind. pe ag <a Center of high barometer. pees 
1872. Jan. 31| 4°°4| N.W. 0 30°25 Nashville. 30°50 
Feb. 23 6°71 N. 5: 30°07 Norfolk, Va. 30°10 
March 5} —1:2| N.W. 0 29°95 icago. “30 
April 18} 28-1 N. 0 29°97 Near Long Island. 30-00 
ay 3/+39°2| S.E. 3 30°26 Near New York. 30°30 
June 2] 48°2 N. 0 30°01 e Huron 30°10 
July 25] 56-0 W. 5 30°08. Gulf of Mexico 30°20 
Aug. 31] 54:0 Ww. 0 29°70 ino 30°10 
Sept. 4) 43°3 N. 0 30°05 Pittsburg, Pa 30°10 
Oct. 30] 29°3| N.E, 0 | 30°57 Main 30°60 
Nov. 30} 10:3} W.S.W. 0 29°75 Georgia. 30°50 
Dec. 28}—20-0 N. 0 30°10 Nashville 30°60 
1873. Jan. 30|—26-0| N.W. 0 30°25 Pennsylvania. 30°30 
Feb. 24) —6-0 W. 0 29°77 Nashville. 30°30 
March 5 8 N.W. 0 30°53 oxvi 30°70 
April 1) 31°8| W. 0 30°08 Chesapeake Bay. 30°10 
May 4! 33:2 N. 1 29°96 uisvi 30°10 
une 1) 46:3 W. 0 30°35 Chesapeake Bay. 30°40 
July 19} 55-0! NW. 5 29°94 alifax 30°20 
Aug. 24) 51-0 N. 0 30°06 e Hur 30°40 
Sept. 15) 38:0 N. 0 30-27 Washington, D, © 30°20 
Oct. 30) 29-4 N. 0 30°47 w Yor 30°40 
Nov. 29} 15-5 W. 0 30°47 Wheeling, Va. 30°60 
Dec. 31} 10°0| W. 0 | 3033] Wilmington, N. C. 30°60 
1874. Jan. 17} 3-6] W. 0 30°43 Lynchburg, Va. 30°50 
Feb. 2) —1-4| N.N.E. 0 30°72 Quebec. 30°80 
Mar. 24) 12-2) N.N.W. 0 30°32 St. Louis. 30°70 
pril 5) 14:8 W. 0 Balti ‘| 30°40 
May 12} 32-7 N. 0 30°52 Long Island 30°50 
June 14) 46-°3| N.N.W. 0 30°26 shin 30°30 
J 4| 57-0 8. 0 | 30-05 Charleston, 8. C 30°10 
Aug. 29} 50:9 N. 0 30°06 Gulf of St. nce 30°10 
Sept. 23) 43°5| N.W. 0 30°28 Baltimore. 30°30 
Oct. 15} 32:0] N. 0 | 30-41 Virginia. 30°50 
Nov. 14| 19-1 N. 0 30°67 New York. 30°70 
The preceding considerations appear to me to prove that the 
extremely low temperatures which occur at irregular intervals 
im every month of the year, but particularly in the winter 
months, are due mainly to the descent of cold air in the neigh- 
borhood of an area of ‘high barometer; and this descent of the 
air results from the outward movement which generally takes 
Place from the center of an area of high barometer. 
Long continued periods of cold weather. 
Sometimes we have a period of severe cold continuing ten 
days or even longer. The most remarkable cases of this kind 
