44 



DISCUSSION OF THE VERTICAL COMPONENT 



Subtracting each A-aluc of Tabk^ I from its respective monthly mean as given in 

 Table II, and converting the remainder into parts of the force, we find the regular 

 solar-diurnal variation presented in the following table : — 



Table II] 



. — Keuular Solae-Diurnal Variation of the Vertical Force expressed in 





PARTS OF TUB FORCE. 





A plus sign indicates a greater, a minus sign a less value than the mean. The first three places of | 





decimals 0.000 have been placed on the side. 







1841-5. 



Oh 



2 



4 



6 



8 



10 



Noon. 



14 16 



18 1 20 



22* 



+20'».6 



January 



—059 



+238 



+040 



—026 



—026 ! +172 +172 



+304 1 —092 



—323 —224—158 







February 



—198 



+033 



—132 



—165 



+099 ' +231 1 +264 



+306 



+198 



—264 —330 —132 







March 



—178 



+086 



—046 



—112 



+086 +119 1+251 



+317 



+020 



_178 —145 1—211 







April 



—353 



—155 



—122 



—023 



+175 +274, +274 



+340 



+241 



—023 —320 —320 







May 



—412 



—346 



—214 



+049 



+247 +280 1+346 



+445 



+313 



4-016 —313 —412 





o 



June 



—528 



—297 



—198 



—033 



+198 +396 1+594 



+462 +363 



— 0C6 —429 —462 







July 



—571 



—406 



—241 



+056 



+221 1 +419 1 +584 



+551 1 +386 



_043 , —406 —538 







August 



—485 



—386 



—287 



—089 



+109 1 +406 ' +736 



+571 ' +340 



—023 1 —386 —485 







September 



—469 



—304 : —271 



—205 



+092 1 +323 +521 



+521 +356 



+026 ' —271 —337 







October 



—099 



+066 1 —000 



—099 



+231 +198 1+198 



+198 —033 



—198 1 —264 1 —198 







November 



—043 



—043 —142 



—109 



+086 ! +122 +254 



+221 —010 



—076 —109 ' —109 







December 



—059 



+ 139 +040 



—059 



+040 ' +139 : +205 



+205 —092 —290 [ -191 —125 





Year 



—287 



—115 



—131 



—068 



+129 +257 1+366 



+377[+165— 1211—282 



—290 





Summer 



—469 



—317 



—221 



—040 



+175 



+350 +508 



+482 1 +333 —020 —353 



—426 







Winter 



—106 



+086 



—040 



—096 



+082 



+162 +224 



+274-000 —221 —211 



—155 





Multiplying the above numbers by Y=r2.83, we obtain the solar-diurnal varia- 

 tion in absolute value. 



Table IA 



. ItEGULAR SoLAR-DiURNAL VARIATION OF THE VERTICAL FORCE IN ABSOLUTE 





Measure. 





A greater force than the mean is indicated by a plus sign, a less force by a minus sign. The first two | 





places of decimals 0.00 are placed on the side. 







1841-5. 



Oh 



2 



4 



6 



8 



10 



Noon. 



14 



16 



18 



20 



22>' 



+20"°.6 



January 



—076 



+305 



+051 



—034 



—034 



+220 



+220 



+389 1—118 



—415 



-289 



—203 







February 



—254 



+042 



—170 



—212 



+127 



+296 



+338 



+ 508 , +254 



—338 



—423 



—169 







March 



—229 



+110 



—059 



—144 



+ 110 



+ 152 



+321 



+406 [ +025 



—228 



—186 



—271 







April 



—452 



—198 



—157 



—030 



+224 



+351 



+351 



+436 



+309 



—030 



-410 



—410 





_ 



May 



—529 



—444 



—275 



+064 



+317 



+ 360 



+444 



+571 



+402 



+021 



—402 



—529 





o 



June 



—677 



—380 



—254 



—042 



+254 



+508 



+ 761 



+592 



+465 



—085 



—550 



—592 





o 



July 



—732 



—520 



—308 



+072 



+283 



+537 



+ 749 



+706 



+495 



—055 



—520 



—690 







August 



—622 



—495 



—368 



—114 



+ 140 



+520 



+943 



+732 



+436 



—030 



—495 



—622 







September 



—601 



—389 



—346 



-263 



+118 



+415 ; +668 



+668 



+457 



+034 



—347 



—431 







October 



—127 



+085 



—000 



—127 



+296 



+254 



+254 



+254 



—042 



—254 



—338 



—254 







November 



—055 



—055 



—182 



—140 



+072 



+157 



+326 



+'-'83 1 —013 



—098 



—HO 



—140 







December 



—076 



+178 +051 



—076 



+051 +178 



+263 



+263 [ —118 —372 



—245 —161 





Year 



—368 



—148 , — 168 1 —087 



+165 1 +329 



+470 +483 +212 



—156 



—364 —372 





Summer 



—601 



—406 1 —284 —051 



+224 +448 



+651 +618 , +426 



—025 



—453 , —546 







Winter 



—136 +110 1 —051 —123 



4-106 I +207 



+288 +351 —000 



—283 



—271 1 —199 





Anntial LiequalUy in the Diurnal Variation of tlie Vertical Force. — If we examine 

 the average curve of the diurnal variation as observed throughout the year, and 

 shown on diagram (A) by a fuU black line, we find the principal maximum value 

 about 1 P. M., and the principal minimum value about 9g P.M.; besides these 

 characteristic values there is an indication of a secondary maximum about 2 A. M., 

 and of a secondary minimum about 4 A. M. Dividing the year into a summer 



