
ON ELECTRICAL OBSERVATIONS AT KEW. 165 
Tasle LXXIV. 
Greatest and least mean daily electrical tension in each month, from August 
1843 to December 1844, both inclusive, with their differences, and days of 
the month on which they occurred. 



Month Mean daily electrical Days of the month on which the 
‘ tension. 2 mean electrical tension was 
Difference. 
1843 and 1844, | Greatest. | Least. Greatest. Least. 
div. div. div, 
August ......... 66°33 3°25 63°08 18 29 
September ...... 77°50 8°50 69-00 14 30 
October ......... 116°25 12°75 103-50 29 4 
November ...... 447°50 10°75 436°75 12 21 
December ...... 225-00 7°75 217-25 13 22 
January ......... 925-00 13°25 911°75 3 28 
February 743°75 8°50 735°25 13 18 
NEATH ascvecsascs 77°50 1:50 76:00 6 25 
RPIEH  cccssces ...| 425°00 12:00 41300 1 20 
HUES? Sacadeccavce: 64°75 7°50 57°25 6 19 
BINGE ids 0k Sex 49°37 5°25 44°12 23 6 
TONY! senceoss sens 63°12 9°50 53°62 23 29 
August ......... 60:00 12°50 47°50 29 8 
September ...... 146°25 3°87 142-38 I 16 
October ... .....| 243°75 3°75 240-00 28 9 
November ...... 212°50 12°50 200-00 22 15 
December ...... 800-00 18°33 781:66 6 29 

The greatest mean daily electrical tension occurred in January 1844, and 
the least in March 1844: the difference (923°5 div.) is the range of the mean 
tensions during the seventeen months. 
The numbers in this table bear testimony to the same general fact which 
we have already noticed in the discussion of the three years’ observations, viz. 
the great increase of electric tension in winter; but from the nature of the 
quantities recorded, they are not comparable with the annual curves deduced 
from the observations of 1845, 1846 and 1847, and from those of sunrise 
and sunset during the five years. 
From Table LXXV. we learn that in every month the electrical tension 
exceeded 79 div. of Volta’s electrometer No. 1. In November 1843, Janu- 
ary, February, March, April, and December 1844, the highest observed ten- 
sions at the four observation-epochs were between 1000 div. and 1500 div., 
or between 10° and 15° of Henley’s instrument. In the remaining months, 
with the exception of August 13843 and June 1844, the highest tensions 
were between 100 div. and 500 div., or 1° and 5° of Henley, and in the two 
excepted months they were respectively 95 div. and 80 div. The effect of 
the annual progression is very apparent, the higher tensions being confined 
to the winter months. : 
During the seventeen months the electrical tension was never observed 
below 2 div. of Volta No. 1, except on one or two occasions on which the 
tension was too feeble materially to influence the instrument. ‘The numbers 
-in the column of least absolute tensions give the lowest observed tensions by 
Volta’s instrument in the respective months. 
Tables LXXVI. and LXXVII. exhibit the monthly distribution of all the 
observations at the four observation-epochs, together with the value of the 
mean electrical tension at each observation-epoch in each of the seventeen 
months. 
