ON THE RAINFALL IN THE BRITISH ISLES. 445 
Altitude Correction. 
Factors to be multiplied into the mean annual correction. 
Greenwich. Calne. |” Rotherham. 
Year. 10 ft. | 22 ft. | 38 ft. [61 ft. | 20 f. | 10 £t. | 20 ft. | 25 ft. 
MUEIY <ccaccecses, sssiecsest liek Ol "92 "94 "91 "96 xe oo re 
OUMUIATY "...\..lccssccesseesl G4] "GO 84] °79 "94. ‘97 "95 ‘91 
BEEP (22 cst sedeeisnd'sacdh T'oz | 1702 94. |. "OX ‘91 “SI “78 "79 
BRIEF 5. -. su feri(seclsvesacee| 2°09 ll! 1°08 |) Tog” too "98 "99 | 99 "96 
UIE << <20 cv coecsisadensess|eNcO2 W X°02: ||) Laon eeeery I'04 Tor | Toz } ros 
BIH eso c.0s.slekseanodarnaes Kou GOs.) exo) |) rsr7, 1°03 1704. | 1°07 | 1°06 
Pitas. Netssccevessst |) 899i] TOS. | xen rene 1°05 1705 | 1°06 | 1°06 
PEEEATESE eis ocpiasioa's s0as<ec'es Or | moo | I°x2 |/anog 1°05 og | 10 | 1°13 
Boptemiber’ ...\...0c.-..--- 2+) E208] ror | 10g) | *xsr4! 1°03 1:06 | 1°07 | 1°08 
BGROUED sos00-Neseesccaess ces too | I'o2 | Tor] r'o4 1'02 Lior |) E02, | i703 
Wovember ...........0..<0-5| “98 87 "92 ‘gl Io I'00 "99 "99 
MacampPer” /..2:......5--2-.| 98 “81 “77 "74. "99 “96 “96 "94 
Example 1.—Observed fall at Royal Observatory, Greenwich, in July 
1862 to 1865 at 51 feet above the ground was 3°57; required the probable 
fall at the ground. 
Mean annual correction for 51 feet=+623 x 1:11=-69, 
3°57 :69=5:17 
_ (observed fall was 5-14). 
Example 2.—At Bishopwearmouth the gauge is 30 feet above the ground. 
The monthly percentage of total annual fall is in January 46, and in July 
8-9; required the probable true percentage at the ground level. From the 
above Table -93 may be taken as the factor for January and 1:09 for July; 
then 4-6+-93=4-9, and 8:°9+1:09=8-2, 
Two other matters alone remain for consideration in this Report,—(1) the 
rainfall of the past two years for 1866-67 in continuation of previous 
papers published by this Association, and (2) the results of the examination 
of rain-gauges in situ. 
With reference to the first subject, we have thought it expedient to draw 
up a Table showing the rainfall of the ten years 1850-59; also the same 
values reduced to the mean of fifty years by the application of the correction 
suggested in the British Association Report 1862, then the actual fallin each 
year since 1859. From thence we have determined the percentage of excess 
or deficiency in each year, which we believe to be far the clearest mode of 
exhibiting the fluctuations of rainfall. 
