ON ELECTRICAL OBSERVATIONS AT KEW. 159 

A Taste LXVI. 
Mean electric tension at sunrise in each month from August 1843 to July 
1848 inclusive, with the mean monthly electric tension deduced from them. 
en ERs ncn eR 
Year.| Jan. | Feb.|Mar.| April.|May.| June.| July. |Aug.| Sept. |Oct. | Nov. | Dec. |Mean. 

diy. | diy. | div.| div. | div.| div. | diy, | div.| div. | div. | div. | diy. diy. 
aaa ate a. -'aiwie as ane dob ... |15°7| 26°1| 174) 10570) 40°7 
1844.| 127-0] 93:9) 23°6) 42°0| 1171) 12-7 17:3 | 25:8] 19-3} 24:9) 59-3) 116°5) 48-0 
3| 29-0] 31:2 | 26°9| 20°2| 16:2 | 18-5) 21°9| 30-5) 62:3) 69:2) 43-7 
67°3| 53-4) 35°5 | 33-9) 19-0 | 24°3 | 19-3) 21-0 | 32°4 33°3| 81°6) 43°8 
1847.| 176:9| 92°6| 54°8) 43°6 | 19:1 20:8 | 36°3 | 22-0) 22°9| 30°5| 40°3) 48-2) 51:3 
40:5] 88-7| 44°3 | 46°5| 21:3] 31°2 
Mean.| 118-3 77°1| 51-0) 39°4| 27°5| 18-6] 25-1 | 20°3) 22-4) 27°5| 59-3) 71-6) 46°8 














TABLE LXVII. 
Number of positive readings of the electric tension at sunset in each month 
from August 1843 to July 1848 inclusive. 

Year.| Jan.| Feb.|Mar.| April.|May.| June.| July. |Aug.| Sept. Oct.'Nov.|Dec.|Sums. 

— |_| | ————| | ——— - | | —<__ —_— | 

—_— 
TOA echt, oad osdul Feta 4 tt lok ik 20 12.c0) 2efe2e) ol} 138 
1844.) 27| 25| 27| 29| 30) 29| 28} 28) 25] 27| 27| 30] 332 
1845.| 26} 26| 22] 25| 25) 26] 29) 27) 29} 31) 26) 27) 319 
1846.| 30} 24| 29} 26! 29) 28] 28) 29) 29] 28) 30) 29) 339 
1847.| 29| 27| 29| 26} 27) 26} 30] 27) 29] 30) 30) 29) 339 
we | 188 


| | ——_| | | | | | ee | 
Sums. 141| 127|135| 129 | 139| 136 | 143 |136| 142 | 140/141 | 146| 1655 




TasrLe LXVIII. 
Mean electric tension at sunset in each month from August 1843 to July 
: 1848 inclusive, with the mean monthly electrie tension deduced from 
them. 
ie OS ee ae Cee eee ee 
Year.| Jan. Feb. | Mar. | April.|May.| June.|July.|Aug.| Sept. | Oct.| Nov. | Dec. |Mean. 












‘ diy. | div. | diy. | diy. |-div. | div. | div. | div. | div. | div.] div. | div. | div. 
1843.) ... ade as 5 5 ' aoe .-. 138°0| 49-2 |44°0 |164°8 | 58-7 
1844./173-1 |156-5 | 48-7 | 39-3 |32°1 | 34-6 |38°3 40-1 | 46°3 [56-8] 58-6 |225-0 | 79:0 
1845.| 90°2|151:2| 60°6| 61°3 |43-5 | 34:2 |29°8 |43°4|50°7 |57°2| 74:4] 84:4 | 64°6 
1846.) 86°5| 78111621} 75:1 |41-5| 44:0 |46-8 |35°6 | 34°4 |72°9| 60°1 |181-2 | 76:7 
1847.|342-2 |170°5| 66°5| 50°7 (58-4 | 37-0 |54:9 39-4 | 42°7 |42°2| 78:3) 86°3| 89-6 
1848./158'6 | 61°3| 81:7 |124:1 |82°-0| 61°2 |50°0 
_~ (Mean,}171-2 j1248 85°6 | 68-2 |51°3 | 42°2 [44-0 39-3) 44°6 [54:8] 87-1 127-4 | 78:4 

"The results of the five years’ observations furnish the ordinates of two annual 
curves, viz. that exhibiting the annual period of the electrical tension at sun- 
rise, and that exhibiting its aunual period at sunset. As before remarked, 
_the sunset curve is superior to that of sunrise. In fig. 17, these curves are 
projected on the same scale, so that the eye at once recognises the monthly 
differences between them. ‘The annual curve, as deduced from the observa- 
tions of 1845, 1846 and 1847, is also added for the sake of comparison. It 
will be observed that the three curves agree in presenting the slight increase 
_of tension in July as compared with both June and August, which forms a 
_ secondary but very inferior maximum, and to which allusion has already been 

