IN RAIN AND SNOW, IN THE UNITED STATES. 



19Tf 



Marietta, Ohio . . 

 Steubenville, Ohio 

 Alleghany Arsn. Pa. 

 Detroit, Mich. . . 

 Fort Brady, Mich. 

 Fort Ripley, Min. 

 Fort Snelling, Min. 

 Milwaukee, Wis. . 

 Dubuque, lo. . . . 

 Muscatine, lo. . . 

 Fort Madison, lo. 



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°2S' 

 40 25 



40 32 



42 20 

 46 30 



46 19 



44 S3 



43 03 

 42 30 



41 26 

 40 37 

 39 52 

 38 40 



38 37 



38 28 



39 21 

 35 48 

 35 23 

 34 14 

 33 44 

 3748 

 3835 



45 40 



47 10 

 57 03 



Long. 



8i°29' 

 80 41 

 80 02 

 82 58 

 84 43 

 94 19 



93 10 

 87 55 

 go 40 



91 05 

 91 28 



89 56 



90 10 

 90 16 

 90 15 



94 48 



95 03 

 94 29 



96 38 



93 41 

 122 26 



121 28 



122 30 

 122 25 

 13518 



Height 

 above 



feet. 

 580 

 670 

 704 

 580 

 boo 



1 130 

 820 



591 

 666 

 586 

 600 

 800 



450 

 481 

 472 

 896 

 560 

 460 



645 



660 



170 



82 



50 

 300 



Epochs. 



817-67 

 830-67 

 836-59 

 836-66 

 836-56 

 850-67 

 836-67 

 841-66 

 851-66 

 846-66 



843-58 

 836-56 



837-67 

 S40-62 

 S36-67 

 836-57 

 837-61 

 843-60 

 840-67 



849-67 

 849-67 

 849-67 

 847-67 



Years 



of 

 record. 



3-56 

 3-46 

 2.94 

 2.50 



2.53 

 2.09 



2.15 



2.53 

 2.79 

 3-57 

 3-5° 

 3-30 

 3-55 

 3-51 

 3-41 

 2.64 



3-°3 

 3-36 

 3-17 

 4-54 

 i.8i 

 1.63 

 3-24 

 3.66 

 6.95 



^. 



0.60 

 0.51 

 0-53 

 0-75 

 1-33 

 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 

 3-07 



m. 

 0-34 

 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 



0-39 

 0.91 

 0.66 

 0.68 



O.IO 



0.59 



0.45 

 1.08 

 0.45 



1-25 



in. 

 0.13 

 0.15 

 0.15 

 0.09 

 0.24 

 0.21 

 0.19 

 0.07 



0-45 

 0.26 

 0.17 



0-33 

 0.41 



O. II 



0.19 

 0.19 

 0.23 

 0.25 

 0.38 

 0.36 

 0.52 

 0.58 



0-39 

 0.24 

 0.56 



273 

 266 

 270 

 266 

 207 

 257 

 258 

 257 



255 



264 



260 



291 



291 



287 



267 



257 



290 



282 



279 



18 



70 



67 



81 



82 



146 



114 

 132 

 158 

 241 

 271 

 97 

 129 

 177 

 161 



247 

 271 



159 

 162 

 171 

 140 

 121 

 201 

 194 

 195 

 207 



87 

 100 

 125 

 136 

 274 



194 

 144 

 134 

 253 

 54 

 331 

 80 

 69 

 338 

 "5 

 65 

 28 

 268 

 230 

 270 

 351 

 356 

 ^93 

 351 

 196 

 142 

 150 

 131 

 154 

 25 



Prob. 

 error. 



+0 



The observed and computed (by the above formulae) 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' 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. 















"H 







1 



J3 









v 



oT 





f 





Mean 



Month. 



a 3 



■5 1 



li 





A 



m ?, 



c " 



-Si 



i i 



1^ 



■- i 



..-i 



V- rt 



£■2 



K 2 



^2 



.5 S 



of 

 18 Sta- 





'■V =^ 



a >- 



u >. 



%b 



° i^ 



!^ 



■r- 





-.'■z 





^ w 



^i:; 



t- 







•&K 



tions. 





" 



W" 



^" 



d" 



m 



•A "^ 



A" 



C CO 



&- 



'^ 



•A "' 



is" 



g " 



a" 



s-* 



pq '^ 



A'' 



^'' 





January 



1. 01 



.87 



.99 



1.06 



1. 00 



.07 



.99 



.04 



.8q 



.84 



.qo 



.88 



•04 



.88 



.89 



■79 



.82 



.91 



.92 



February 



.82 



• 74 



.8s 



.80 





94 



.P6 





84 



.Si 



.96 



■77 





88 



.81 





8q 





86 





81 



.84 



•77 



.84 



.84 



March 



1.02 



1. 00 



•QS 



.96 





98 



I. OS 



I 



OI 



.98 



•qi 



■ 01 





92 



.82 





93 





88 





94 



1. 12 



1.07 



.92 



.96 



April 



■07 



•9S 



1. 00 



1. 00 





04 



1.02 



I 



04 



1.02 



1.04 



■ 03 





99 



1.04 





98 





87 





00 



•95 



1. 01 



113 



1. 00 



May 



i.ij 



1.22 



1.04 



1.04 





10 



1.06 



I 



01 



1.06 



1.24 



1.31 



I 



24 



1.25 



I 



17 



I 



18 





09 



I. II 



1.07 



1. 10 



113 



June 



•07 



.00 



.84 



.86 





8q 



.82 





91 



1.07 



i.oS 



I.O^ 



I 



06 



.88 





86 





93 





13 



■97 



•97 



1.06 



.96 



July 



.qi 



.08 



1.02 



.92 





08 



■87 





8q 



1. 01 



1. 01 



■ 05 



I 



01 



1.08 





q8 



I 



12 





08 



1. 10 



•97 



1.25 



1. 01 



August 



I. II 



i.iS 



l-^^ 



1. 31 





10 



1. 14 



I 



14 



1. 18 



1. 21 



i-SS 



I 



17 



1.30 



I 



26 



I 



35 





22 



1. 17 



1. 21 



1.20 



1.22 



September 



.82 



.81 



• QI 



i^o6 





94 



.05 





80 



.88 



.89 



■03 





qi 



.83 





03 



I 



07 





99 



1. 01 



• 94 



•91 



•92 



October 



1. 10 



1. 01 



1.07 



■ 03 





89 



.08 





07 



.90 



•7S 



■02 





88 



1.06 





9b 





94 





91 



•95 



•97 



1. 01 



.96 



November 



1. 06 



1.25 



1.05 



1.02 





OS 



1. 12 



I 



17 



1.05 



.q8 



■ 05 





97 



1.03 



I 



01 





88 





95 



• 96 



1. 00 



•83 



1.02 



December 



1. 10 



1.04 



■99 



1.07 





03 



1. 10 



I 



14 



1. 01 



1.05 



I-I3 



I 



08 



1.02 



I 



09 



1.06 



1. 01 



1.05 



1. 18 



•85 



1.06 



1 The quantiUj called A in the preceding equations, 



