OF THE MAGNETIC FORCE. 



55 



Table X. — Computed Solar-Diurnai, Variation of the Vertical Force, expressed in 



Absolute Measure. 

 The first two places of decimals 0.00 are placed on the side ; + indicates more, — less than the monthly 



average. 



o 

 o 

 d 



1841^. 



0" 



2 



4 



6 



8 



10 



Noon. 



14 



16 



18 



20 



22" 



+20">.6 



January 



February 



March 



April 



May 



June 



July 



August 



September 



October 



November 



December 



+025 

 —072 

 —135 

 —385 

 —516 

 —601 

 —706 

 —630 

 —512 

 —055 

 —059 

 —008 



+165 

 —085 

 —017 

 —266 

 -461 

 —419 

 —550 

 —499 

 —431 

 +030 

 —089 

 +110 



+123 

 —178 

 —008 

 —165 

 —262 

 —245 

 —279 

 —338 

 -351 

 —030 

 —148 

 +097 



—030 

 —123 

 —072 

 +008 

 +068 

 —042 

 +034 

 —157 

 —207 

 —008 

 —131 

 —008 



—046 

 +063 

 —013 

 +216 

 +309 

 +241 

 + 305 

 +144 

 +076 

 +165 

 +017 

 —008 



+ 161 



+258 

 +207 

 + 338 

 +372 

 +533 

 +537 

 +563 

 +431 

 +309 

 +207 

 +182 



+355 

 +436 

 +372 

 +402 

 +448 

 +711 

 +723 

 +859 

 + 673 

 +300 

 + 313 

 +330 



+258 

 +465 

 +304 

 +436 

 +554 

 + 681 

 +744 

 +801 

 + 677 

 +182 

 +233 

 +203 



—080 

 +203 

 +059 

 +317 

 +423 

 +398 

 +457 

 +414 

 +436 

 —004 

 +046 

 —114 



—351 

 —241 

 —165 

 —025 

 —000 

 —068 

 —051 

 —072 

 +047 

 —237 

 —123 

 —313 



—376 

 —444 



—275 

 —385 

 —402 

 —503 

 —499 

 —448 

 —321 

 —377 

 —161 

 —304 



—203 

 —283 

 —258 

 —491 

 —533 

 —685 

 —714 

 —639 

 —516 

 —275 

 —106 

 —165 





Year 



Summer 



Winter 



—309 

 —558 

 —046 



—211 

 —440 

 +017 



—152 

 —275 

 — 021 



—055 

 —050 

 —051 



+123 

 +212 

 +034 



+343 

 +465 

 +216 



+495 

 +634 

 +338 



+457 

 + 651 

 +271 



+211 

 +410 

 +021 



—131 



—025 

 —228 



—368 

 —423 

 —321 



—402 

 —600 

 -216 





A graphical representation of the above tabular numbers is given in diagram H, 

 based upon the three variables : the hour of the day, the month, and the difference 

 of vertical force from the normal monthly value. The contour lines of the mag- 

 netic surface differ 0.001 of vertical force (in absolute measure). Full lines indi- 

 cate greater value, lines of dashes less value than the normal, dotted lines represent 

 the normal value. 



