512 MR JOHN ALLAN BROUN ON THE HORIZONTAL FORCE 
3. The following table contains the yearly means of the horizontal intensity, 
commencing the year with each month successively, and the rate of change of 
this mean from month to month. 
TABLE I.— YEARLY MEAN HorizonTAL FORCE (minus A CONSTANT), WITH ITS MONTHLY 
VARIATION AT MAKERSTOUN IN SCOTLAND, AND HoBARTON, VAN DIEMAN ISLAND, 
1842-49. 1:00 = (WHERE X IS THE WHOLE HoRIzONTAL FORCE AT THE 
ae Soe 
10000 
RESPECTIVE PLACES). 



















































Makerstoun. Hobarton. Makerstoun. Hobarton. 
YEAR. wh OM 8 Bee SASS. AE ees YEAR. pod Mor SP us! : 
Mean. |Change.| Mean. |Change. Mean. | Change. | Mean. Change. 
1842 Jan. to 1842 Dec. | 23°50] ., 22°70 | 5.9|1845 July to 1846 June |109°83 14 \L13°99 i 
Feb. 1843 Jan, | 26°58] S00| 25-48) 228) Aug. July |110°97| G.3 [11480 Nee 
Mar. Feb. | 29°58 2-46 28°08 9:97 Sept. Aug. /111°78 0:97 115°50 0°85 
April Mar. | 32°04 277 30°35 9°50 Oct. Sept. |112°75 0-94 |116°35 0°78 
May April} 34°81 2-20 32°85 1:81 Noy. Oct. |113°59 110 Vals 1-03 
June May | 37:01 9-90 34°66 1:99 Dee. Nov. |114°69 156 11816 1°28 
July June | 39°21 216 36°65 2-07 1846 Jan. Dec. |116°25 1:43 119°44 115 
Aug. July | 41°37] 9.59 38°72 175 Feb. 1847 Jan. |117°68 1-04 |[£20°59 0-79 
Sept. Aug. | 43°59 9:94 40°47 1:83 Mar. Feb. |118°72 1-21 22138} 9.69 
Oct. Sept. | 45°83 2-08 42°30 164 April Mar. |119:°93 1-15 |L22°00 0°61 
Nov. Oct. | 47:91 257 43°94 9:25 May April |121°08 0:87 122°61 0:97 
Dec. Nov. | 50°48 9-59 46°19 9-20 June May 121-95 1:59 123°58 1-07 
1843 Jan. Dec. | 53°00 2:60 48°39 2°48 July June |123°52 1:00 |124'65 1:07 
Feb. 1844 Jan. | 55°60 2-68 50°87 9-68 Aug. — July |124°52 1°36 125-72 114 
Mar. Feb. | 58:28 2-73 53 55 2°53 Sept. Aug. |125°88 1°35 126-86 O77 
April Mar. | 61°01 2:85 56°08 92-65 Oct. Sept. |127-23 0-42 127°63 0:60 
May April} 63°86 319 58°73 2-97 Nov. Oct. |127°65) 9.5, [128-28 0:93 
June May | 66°98 3:50 61:70 3:09 Dec. Noy. /128:00 0-68 28°46 ~0-12 
July June | 70°48 373 64:79 3-39 1847 Jan. Dec. |128°68 ~ 0-10 128°34 0:02 
Aug. July | 74:21 3-43 68°11 2:96 Feb. 1848 Jan. |128°58 0:06 |128'36 0-17 
Sept. Aug. | 77°64) 5.58 71°07 9-89 Mar. Feb. |128°64 0:22 12853) 9.38 
Oct. Sept. | 80°82 2-98 73°89 273 April Mar. |128°86 0-56 (28°91 0-70 
Nov. Oct. | 83°80 9-63| 19°62| 9.95 May April|129°42| 44, |129°61 0°74 
Dec. Nov. | 86°43] 5.65 78°95 | 5.39 June May |130°50 0:72 |130°35| 9.96 
1844 Jan. Dec. | 89°05 1:90 81°33 9:00 July. June |131°22 0-97 [13121 0°45 
Feb. 1845 Jan. | 90°95 181 83°33 994 Aug. July |152°19 0-91 (£31°66 0:89 
Mar. Feb. | 92°76 1-94 85°57 2-56 Sept. Aug. |133°10 0-58 |132°55 1:43 
April Mar. | 94°70 160 88:13] 5.35 Oct. Sept. |133°68 1:88 |183°98 
May April| 96°30, 1-21 90°48 9-20 Nov. Oct. |135°56 1-20| « ce 
June May | 97°51| 5.49| 92°68] 9.94 Dec. Nov. |136°76 0°35 
July June | 98°70 0:89 94°72 1°87 1848 Jan. _ Dee. 137-11 1:39 ’ 
Aug. July | 99°52 0:86 96°59 9-03 Feb. 1849 Jan. |138°43 1-65 
Sept. Aug. |100°38 0°60 98°62 1:35 Mar. Feb. |140°08 1:31 
Oct. Sept. 100°98 | 9.93 100°47 | 5.96 April Mar. |141°39| 7.45 
Nov. Oct. |101°91 0:92 92°53 | 5.93 May April |142-70 156 
Dee. Nov. |102°83 0-57 104°56 172 June May |144°26 2-01 
1845 Jan. Dec. |103°40 1:06 106°28 185 July June |146:27 1-79 
Feb. 1846 Jan. /104:46 1:09 108-13 | j.54 Aug. _duly |147-99 1:50 
Mar. Feb. |105°55 114 109°67 1-41 Sept. Aug. |149°49 175 
April Mar, |106:69| 5.55 [111-08] j.04 Oct. Sept. |151:24| 3.59 
May April 10791] 5.) |112'32 0-87 Nov. Oct. (152-33 1°62 
June May |109:06 0.747 11319} 9.99 Dec. Nov. |153°95 2°16 
; 1849 Jan. Dec. |156°11 





