22 



DISCUSSION OF THE VERTICAL FORCE. 



Tahi.e IX.— Aggreoate and ]\[ean Amount of Disturbances in each Month of the Year. 



The numbers are expressed in scale divisions and referred to a uniform series of bi-hourly observations. The 



mean amount or average magnitude is found by dividing the number in the preceding column by 4 and by 



the number of disturbances found in Table VII. 





Aggregate amount. 











Sum of 4 years. 



Meaa amount. 



1841-42. 



1842-43. 



1843-44. 



1844-45. 



Julv . . 



2593 



1255 



149 



784 



4781 



42 



August 

 September 





791 



1323 



622 



2017 



4753 



43 





1612 



2798 



770 



301 



5481 



44 





1216 



432 



488 



438 



2574 



42 







1564 



603 



1504 



206 



3777 



40 







4187 



560 



831 



872 



6450 



42 



January , 





3899 



2745 



1592 



314 



8550 



47 





3900 



2279 



659 



109 



6947 



45 







1&72 



1898 



2125 



1245 



6940 



42 



April . . 

 May . . 

 Juue . . 





2324 



2111 



1642 



468 



6545 



42 





2445 



1625 



186 



704 



4960 



49 





1472 



723 



934 



168 



3297 



40 



The last column shows that the magnitude of the disturbances is rather irregu- 

 larly distributed over the several months without following any apparent law. 



Table X. Aggregate and Mean Amount op Disturbances in each Month of the Yeaji, 



SEPARATED INTO TWO GROUPS OP INCREASING (-|-) AND DECREASING FORCE ( ). 



The mean amount is obtained by means of the numbers of Table VIII. 





1841-42. 



1842-43. 



1843-44. 



1844-45. 



Sum of 4 years. 



Mean amount. 



+ 



— 



+ 



- 



+ 



- 



+ - 



+ - 



+ 



- 



July 



August 



September 



October 



November 



December 



.January 



February 



March 



April 



May 



Juue 



1130 



555 



835 



999 



653 



2745 



2128 



2615 



671 



1471 



1535 



999 



1463 



236 



777 



217 



911 



1442 



1771 



1285 



1001 



853 



910 



473 



340 



359 



775 



300 



223 



276 



1589 



1538 



910 



1361 



928 



^6 



915 

 964 



2023 

 132 

 280 

 284 



1156 

 741 

 988 

 750 

 697 

 477 







279 

 397 

 250 

 50 i 

 508 



1050 

 462 



1149 

 853 

 170 

 246 



149 

 343 

 373 

 238 

 1000 

 323 

 542 

 197 

 976 

 790 

 16 

 688 



402 

 1568 

 251 

 128 

 154 

 489 

 208 

 76 

 875 

 172 

 598 

 133 



382 

 449 



50 

 310 



52 

 383 

 106 



3S 

 370 

 296 

 106 



35 



1872 

 2761 

 2258 

 1677 

 1534 

 4018 

 4975 

 4691 

 3605 

 3856 

 3231 

 1624 



2909 

 1992 

 3223 

 897 

 2243 

 2432 

 3575 

 2256 

 3335 

 2689 

 1729 

 1673 



37 

 41 

 43 

 43 

 38 

 42 

 48 

 48 

 39 

 43 

 54 

 43 



46 

 45 

 45 

 39 

 41 

 41 

 44 

 39 

 44 

 41 

 42 

 37 



Sums 



16336 



11339 1 8845 



9407 



6867 1 5635 | 5054 1 2572. 36102 [ 28953 







Mean . . . 



43 



42 



The magnitudes of the disturbances, as before, do not appear to follow any law. 



The disturbances which increase the force preponderate over those which decrease 

 it ; the ratio of the annual means is 1.3 to 1.0. At Toronto the reverse Avas found; 

 the disturbances which decrease the force preponderate over those Avhich increase 

 in the ratio of 1.4 to 1.0. 



Diurnal Inequality of tJie Disturhances. — In the bi-hourly combination of the 

 disturbances we make use of the scries of observations extending from February, 



