IN RAIN AND SNOW, IN THE UNITED STATES. 



127 



Marietta, Ohio . . . . 

 Steubenville, Ohio . . 

 Alleghany Arsn. Pa. . 



Detroit, Mich 



Fort Brady, Mich. . . 

 Fort Ripley, Min. . . 

 Fort Snelling, Min. . . 

 Milwaukee, Wis. . . . 



Dubuque, Io 



Muscatine, Io 



Fort Madison, Io. . . 



Athens, 111 



St. Louis Ars. Mo. . . 



St. Louis, Mo 



Jefferson Barr'ks, Mo. 

 Ft. Leavenworth, Ka. 

 Ft. Gibson, Ind. T. . . 



Ft. Smith, Ark 



Ft. Washita, Ind. T. . 

 Washington, Ark. . . 

 San Francisco, Ca. . . 

 Sacramento, Ca. . . . 

 Ft. Vancouver, W. T. . 

 Ft. Steilacoom, W.T. . 

 Sitka, Ala. T 



39=25' 

 40 25 



40 32 



42 20 

 46 30 



46 19 



44 53 



43 °3 

 42 30 



41 26 

 40 37 

 39 52 

 38 40 

 38 37 



38 28 



39 21 

 35 48 

 35 23 

 34 14 

 33 44 



37 48 



38 35 



45 40 



47 10 

 57 °3 



Long. 



8i°29' 

 So 41 

 80 02 

 82 58 

 84 43 

 94 19 



93 IO 

 87 55 



90 40 



91 05 

 91 28 



89 56 



90 10 

 90 16 

 90 15 



94 48 



95 °3 

 94 29 



96 38 



93 4t 

 122 26 



121 28 



122 30 

 122 25 

 ■35 18 



Height 

 above 



feet. 

 580 

 670 

 704 

 580 

 600 



1 130 

 820 



591 

 666 

 5S6 

 600 

 800 



45° 

 481 

 472 

 896 

 560 

 460 

 645 

 660 

 170 

 82 



5° 

 300 



Epochs. 



1S17-67 

 1S30-67 

 1836-59 

 1S36-66 

 1S36-56 

 1850-67 

 1S36-67 

 1841-66 

 1S51-66 

 1S46-66 

 1S4S-66 

 1S43-58 

 1836-56 

 1837-67 

 1840-62 

 1S36-67 

 1S36-57 

 1837-61 

 1 S43-60 

 1S40-67 

 1S50-6S 

 1S49-67 

 1S49-67 

 1849-67 

 1847-67 



Years 



of 

 record. 



years. 

 48 

 37 

 23 

 21 

 18 

 17 

 22 



23 

 15 

 19 

 IS 

 16 

 19 

 28 



3-56 

 3-46 

 2.94 

 2.50 



2-53 

 2.09 



2.15 

 2-53 

 2.79 

 3-57 

 3-5° 

 3-3° 

 3-55 

 3-5' 

 3-4i 

 2.64 

 3-°3 

 3-3° 

 3-17 

 4-54 

 1. Si 

 1.63 

 3-24 

 3.66 

 6.95 



B x 



0.60 

 0.51 

 o-53 

 o-7S 

 i-33 

 1.65 

 1-57 

 0.92 

 1.32 

 1.27 

 1. 17 

 1. 16 

 1-35 

 1.08 

 1.20 

 1.74 

 0.69 

 0.79 

 0.94 

 0.65 



2-37 

 2.04 

 2.46 

 2.96 

 3-o7 



in. 

 °-34 

 0.12 

 0.40 

 0.17 

 0.07 

 0.25 

 0.13 

 0.30 

 0.20 

 0.32 

 0.21 

 0.74 

 0.79 

 0.41 

 0.44 



°-39 

 0.91 

 0.66 

 0.68 



O. IO 



0.59 



o-45 

 1.08 

 0.45 

 1-25 



0.13 

 0.15 

 0.15 



0.09 



0.24 



0.21 

 6.19 



0.07 



0.45 

 0.26 



0.17 



°-33 

 0.41 

 o. 11 

 0.19 

 0.19 

 0.23 

 0.25 

 0.3S 

 0.36 

 0.52 

 0.58 



°-39 

 0.24 

 0.56 



273 

 266 



270 



266 



207 



-57 



258 



-57 



255 



-''4 



260 



291 



291 



2N7 



267 



257 



200 



282 



270 



18 



70 



67 



81 



82 



I46 



114 

 132 

 158 



241 



-7 1 

 97 

 1 20 



177 

 161 

 247 

 271 

 159 

 102 

 171 

 140 

 121 

 201 

 I94 



195 

 207 



87 



I GO 

 125 



136 



274 



194 

 144 

 134 



~5i 

 54 

 35i 

 80 

 69 

 338 

 i'5 

 65 

 28 

 268 

 230 

 270 

 351 

 356 

 193 

 35i 

 196 

 M= 

 150 



151 

 154 

 25 



Prob. 

 error. 



+0.14 

 .10 



The observed and computed (by the above formula?) values of monthly rain-fall 

 at each of the 95 stations are shown graphically on the accompanying plates I. to 

 V., the former by dots, the latter by continuous curves which are obtained by com- 

 puting the rain-fall for periods of thirty days, or for .each month. 



The preceding results, by means of plates I to V, can be further generalized 

 by combining into groups all stations exhibiting the same characteristics in their 

 annual distribution of rain. For this purpose each observed monthly amount, at 

 any station, was divided by the average monthly amount 1 at the station ; we thus 

 obtain the annual fluctuation in a manner which admits of more ready comparison. 



The distinctive groups, as far as our material at present permits of their recog- 

 nition, are the following: — 



Type I. — Atlantic sea-coast from Portland to Washington. 

 Characteristics : Three nearly equal maxima, about the middle of May, August, and December, and one principal 

 minimum about the beginning of February. The range between the extreme monthly values is small. The 

 August maximum is generally the highest. 















-a" 











3 



.a 









oT 



rt* 





& 



a 





Mean 





u*b 



■3 m 



t :<' 



Si j, 



£ 



7, S3 



c s 





S j/j 



5 ,;. 



•£ so 



c £ 



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Q,g 



£b 



"5 £ 



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of 



Month. 



£ QJ 



s S 



•J 5 



'£ s 



cT S 



ffl ?! 







X $ 





> ?. 



° aj 





s 5 





1 £. 



•3 \\ 



2 2 



IS Sta- 





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: ~ c 



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w >> 



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£■>. 



^ ro 



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7] :** 



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tions. 





Q N 



M m 



z « 



c3" 



m M 



£ ■" 



£<* 





fa ** 





~A m 



£" 



z M 



J " 



£* 



« " 



£ N 



£« 





January 



I. OI 



.87 



.99 



1.06 



1. 00 



•97 



.99 



•94 



.89 



.84 



.90 



.SS 



.94 



.88 



.Sq 



■79 



.82 



• ql 



.92 



February 



.82 



■74 



.83 



.So 



.94 



.06 



.84 



.Si 



.96 





77 



.88 



.Si 





Sq 



.86 



.81 



.84 



■77 



.84 



• 84 



March 



1.02 



1. 00 



•93 



.96 



.98 



1 -°3 



I.OI 



.98 



.91 





91 



.92 



.82 





93 



.88 



•94 



1. 12 



1.07 



.92 



.96 



April 



■97 



■93 



1. 00 



1. 00 



1.04 



1.02 



1-04 



1.02 



1.04 





93 



.99 



1.04 





OS 



.87 



1. 00 



.95 



I.OI 



113 



1. 00 



May 



1. 11 



1.22 



1.04 



1.04 



1. 10 



I.06 



I.OI 



1.06 



1.24 



1 





1.24 



1.25 



I 



17 



1. 18 



1.09 



I. II 



1.07 



I. IO 



l'3 



June 



•97 



.99 



•«4 



.86 



.89 



.82 



.91 



1.07 



1.08 



1 



OS 



1.06 



.88 





86 



•93 



I.13 



•97 



•97 



I.06 



.96 



July 



.91 



.98 



1.02 



.92 



1.08 



.87 



.89 



I.OI 



I.OI 





95 



I.OI 



1.08 





q8 



1. 12 



1.0S 



1. 10 



•97 



1.25 



I.OI 



August 



1. 11 



1. 18 



[-33 



1. 31 



1. 10 



1. 14 



1. 14 



1. 18 



1. 21 



1 



33 



1. 17 



I.30 



I 



26 



«-35 



1.22 



1. 17 



1. 21 



1.20 



1.22 



September 



.82 



.81 



.91 



1.06 



•94 



■ 95 



.89 



.88 



.89 





93 



• 91 



.83 





0} 



1.07 



.99 



I.OI 



•94 



.91 



.92 



October 



1. 10 



1. 01 



.07 



.92 



.89 



.98 



•97 



• 99 



•73 





Q2 



.88 



1.06 





Oh 



•94 



•91 



• 95 



•97 



I.OI 



.9b 



November 



1.06 



1.25 



[.05 



1.02 1.03 



1. 12 



1. 17 



1.05 



.98 





95 



•97 



1.03 



I 



01 



.88 



•95 



.96 



1. 00 



• S3 



1.02 



December 



1. 10 



1.04 



•99 



1.07 1.03 



1. 10 



1. 14 



I.OI 



1.05 



1 



13 



1.08 



1.02 



' 



09 



1.06 



I.OI 



1.05 1.1S 



.85 



1.06 



The quantity called A in the preceding equations. 



