Horizontal Component of Magnetic Force. 



237 













TABLE XIIL— 



Continued. 











ivil 



iay. 



January. 



February. 



March. 



April. 



May. 



June. 



July. 



August. 



September. 



October. 



November. 



December. 





0-0 



0-0 



0-0 



0-0 



0-0 



0-0 



0-0 



0-0 



0-0 



00 



0-0 



0-0 



n 



0075 



0101 



0206 



0166 



[0251] 



0263 



0229 



0206 



0191 



0130 



0124 



0089 



>2 



[0089] 



OHO 



0218 



0144 



0220 



0187 



0173 



0346 



0246 



[0186] 



0042 



0039 



13 



0094 



0083 



0140 



[0193] 



0236 



0297 



[0561] 



0439 



0362 



0165 



0107 



0066 



}4 



0089 



0210 



0195 



0165 



0298 



0227 



0703 



0371 



[0245] 



0183 



0150 



[0094] 



.'5 



0096 



0164 



0119 



0235 



0224 



[0278] 



1627 



0341 



0188 



0211 



0128 



0104 



16 



0075 



[0119] 



[0161] 



0257 



0438 



0340 



0421 



0241 



0235 



0202 



[0107] 



0074 



11 



0094 



0092 



0146 





0357 



0331 



0278 



[0297] 



0249 



0188 



0064 



0192 



>8 



0160 



0119 



0151 





[0312] 



0285 



0231 



0213 



0334 



0209 



0099 



0187 



;9 



[0100] 





0215 



0230 



0339 



0308 



0372 



0371 



0261 



[0214] 



0096 



0095 



:o 



0115 





0240 



[0231] 



0252 



0349 



[0277] 



0246 



0139 



0163 



0077 



0128 



!1 



0086 





0206 





0266 





0285 



0221 





0330 





[0135] 



■ ;:in 



01061 



01191 



01774 



03116 



03130 



02899 



03683 



03139 



02484 



02227 



01278 



01223 



From the means at the foot of Table XIII. it will be seen that the least mean is that for January, and the 



greatest that for July ; the same results may be deduced from these quantities as from the ranges of the monthly 



means, thus — 



Jan. & Dec. Feb. & Nov. March & Oct. April & Sept. May & Aug. June & July. 



Ranges, 0-001141 0001234 0-002000 0-002802 0-003134 0-003291 



Differences, 0-000093 0-000766 0-000802 0-000332 0-000155 



The mean of the diurnal ranges is about three times as great for the summer months as for the winter 



months. 



If we take the differences of the monthly means of the diurnal ranges, and of the diurnal ranges of the 



monthly means, we shall have some measure of those irregularities which cause the two to differ. 

 From the means for each couple of months we have the following differences : — 



Monthly means of the dim-nal ranges, minus the diurnal ranges of the monthly means. 

 Jan. & Dec. Feb. & Nov. March & Oct. April & Sept. May & Aug. June & July. 



0-000514 0-000507 0-000527 0-000558 0-000493 0-000449 



The difference is greater at the solstices than in the winter or summer, and is least in summer. 



TABLE XIV. 



-Diurnal Ranges of the Horizontal Component of Magnetic Force, with reference to 

 the Moon's Age and Declination for 1843. 



Moon's 

 Age. 



Mean 

 Diurnal 

 Range. 



Moon's 

 Age. 



Mean 

 Diurnal 

 Range. 



After 



Moon 



farthest 



North. 



Mean 

 Diurnal 

 Range. 



After 



Moon 



farthest 



North. 



Mean 

 Diurnal 

 Range. 



Day. 



15 



u-00 

 2525 



Day. 







0-00 



2217 



Day. 







0-00 



2931 



Day. 

 14 



0-00 



2375 



16 



2232 



1 



1792 



1 



2672 



15 



2022 



17 



2445 



2 



2015 



2 



3249 



16 



1960 



18 



2183 



3' 



2198 



3 



3050 



17 



2026 



19 



2082 



4 



2237 



4 



2981 



18 



2166 



20 



1941 



5 



2037 



5 



2248 



19 



1858 



21 



2093 



6 



3207 



6 



2370 



20 



2168 



22 



1865 



7 



3227 



7 



2332 



21 



2146 



23 



2024 



8 



2756 



8 



2211 



22 



2057 



24 



1630 



9 



2337 



9 



2185 



23 



1925 



25 



1996 



10 



2303 



10 



1942 



24 



2124 



26 



2131 



11 



2405 



11 



2116 



25 



2088 



27 



2596 



12 



2430 



12 



2593 



26 



1962 



28 



3254 



13 



2422 



13 ■ 



2438 



27 



2437 



29 



2310 



14 



2321 











Table XIV. was formed from Table XIII. in the manner indicated for the declination Table II. 



MAG. AND MET. OBS. 1843. 3 O 



