EVAPORATION AT PALERMO. 



463 



Months. 



1865, 



May 



June 



July 



August - . . 

 Septomber 

 October . . 

 Kovember 

 December. 



1866. 

 January . . 

 February . . 



March 



April 



May , 



June 



July , 



August 



September . 



October 



November . 

 December. . 



Siuh. 



0.945 



0. 0G7 

 0.058 

 0.911 

 0.816 

 0. ti8-2 

 0.543 

 0.478 



0.515 

 0.030 



0. 76S 

 0. 88-2 

 0.945 

 0. 967 

 0.958 

 0.911 

 0.816 

 0. 6S-2 

 0. 548 

 0.478 





7.4 

 11.2 

 9.7 

 6.9 

 9.2 

 10.9 

 9.0 

 8.0 



8.9 

 9.2 

 11.3 

 8.2 

 6.5 

 5.4 

 9.8 

 7.9 

 4.4 

 5.4 

 7.6 

 9.2 



Daily 

 ovoiporation. 



Millimeters. 

 5.753 

 7.074 

 7.977 

 7. 490 

 6. 0U2 

 3. 524 

 2.751 

 1. 928 



2.209 

 3.159 



4. 974 

 5.833 

 5.568 

 6. 232 

 8.911 

 7.547 



5. 002 

 3. 236 

 2.863 

 2.495 



Total in the 

 mouth. 



Millimeters. 

 178. 33 

 212. 21 

 247. 30 

 232. 18 

 ISO. 06 

 109. 32 

 82.54 

 59.78 



68.46 



88.46 



154. 19 



175. 00 



172. 61 



186. 95 



276. 24 



233. 97 



150. 05 



100. 32 



8.5. 89 



77.35 



Total 



evaporation, 



Vivenot. 



Millimeters. 



105. 21 



141. 58 



159. 08 



164. ()1 



128. 92 



85.13 



83. 73 



66.69 



77.24 

 84. 72 



121. OS 

 115.41 

 131.41 

 132. 96 

 214. 05 

 183. 46 



122. 75 

 108. 20 



9u. 32 

 71.74 



Difference, 

 G-V. 



Millimeters. 

 1. 605 

 1.313 

 1.554 

 1.416 

 1. 397 

 1. 284 

 0. 986 

 0.896 



0.886 

 1.044 

 1. 274 

 1.516 

 1. 313 

 1. 406 

 1.201 

 1. 275 

 1. 222 

 l!926 

 0. 802 

 1.078 



Millimeters. 

 2. 528 

 3.145 

 3.538 

 2. 913 

 2.149 

 0.439 

 0.482 

 9.531 



0.924 

 1. 321 

 2.785 

 3.371 

 2.648 

 2.634 

 4.442 

 3. 342 

 1.223 

 Cf.l39 

 0. 503 

 0.931 



With the numbers of the 1st, 2d, 3d, and hxst cohimns are, formed 

 twenty equations, which, treated by the method of least squares, yield 

 the three following equations : 



12.50. a+ 503.18. -?)+ 117.15./- 34.75=0 

 503.18 . a+29:i70.00 . '?;+5883.G0 ./-1117.G1=0 

 117.15 . a+ 5883.60 . ^+1119.90 ./- 311.02=0 



-- (2) 



These equations (2) being resolved, we find — 



a=+2.9227; ^=-0. 0651; / =+0. 2642 



The signs of these coefficients agree with the considerations before 

 stated, and the value of /, coefficient of the force of the wind, gives a 

 result more than double that determined by the Yivenot atmometer, as 

 we had supposed would be the case in the independent description of 

 that instrument. 



The daily evaporation of the Gasparin atmometer, indicated by E', 

 would be represented by the formula — 



E'=T . 0.20675-H . 0.01517+F . 0.2642- V . 0.0651+ (sin 7/) . 2.9227 

 where T is the daily mean temperature, H the humidity, F the force 

 of the wind, V the quantity of the clouds expressed in hundredths of 

 the sky obscured, and sin h the sine of the meridian-altitude of the sun. 

 Calculated by this formula, we obtain the following results for the daily 

 evaporations, which in the annexed table are placed beside those ob- 

 served, as well as their relative differences : 



