146 ‘ REPORT—1849. 
In the above table the correspondence within certain limits as to excess 
and defect, in reference to the mean of each period, is well seen; also the 
striking development of the forenoon and evening maxima in each case. 
Upon the continuation of the observations of high tension at midnight, 2 and 
4 A.M.in the winter, the mean line would be lowered and the correspondence 
rendered more complete. 
During the day the movements do not very materially differ from those of 
the aggregate curves for the same periods; this is evident from the follow- 
ing table :— 
TABLE XLV. j 
Synopsis of the principal points in the aggregate and high tension winter 
curves. 
Forenoon | Evening | Evening 
Vv Maximum | Maximum | Maximum 
alue. 
above above above 
Minimum. | Minimum. | Forenoon. 

div. div. diy. 
Aer ere, O05 YP 26:5 558 27°3 
Above 60 div.......... 4403 54°3 10:0 
Diurnal period above 60 div., Summer.—The 668 readings upon which this 
period is based are thus distributed among the twelve observation-hours :— 
TABLE XLVI. 
Number of positive readings above 60 div. at each observation-hour in the 
three summers of 1845, 1846 and 1847. 
| 
Year. mia.!2 a.m.|4 et 
6 a.m./8 a.m./10 a.m.|Noon./2 p.m./4 p.m.|6 pm./8 p-m./10 p.m./Sums. 










Thi eee (eae 3 | 16 | 26| 19 9 7 | 13 | 24 | 42) 68 | 227 
MEAG! leis] caxces Ba ae Ral. ae 5 6 | 10 | 17 | 46| 50 | 218 
GEO A eee eee 3 | 23 | 44) 35 6 6 | 10 | 13 | 35] 48 | 223 
Sums.|...... | oe 8 | 53 | 1071 85 | 20 | 19 | 33 | 54 | 123 | 166 | 668 


It will be at once apparent that these readings are but unequally distri- 
buted. As in the former instances, the greatest numbers occur about the hours 
of the forenoon and evening maxima; but the numbers about noon and 2 p.m. 
are so small as to render it questionable whether we should regard the periods 
deduced from the observations as true representatives of natural phenomena: 
we shall however give them in the same form as the others, and in our re- 
marks solicit particular attention to the maxima occurring in each summer, 
either at noon or 2 P.M. 
Tas_Le XLVII. 
Mean electrical tension above 60 div. at each observation-hour in the three 
summers of 1845, 1846 and 1847, with the mean diurnal period of summer. 







Year. Mid. 2 am.4 a.m.|6 a.m.|8 a.m.|10 a.m./Noon.|2 p-m./4 p.m./6 p.m./8 p.m.|10 p.m.|Mean. 


{ 









| div. | div. |°div. | div. | div. | div. | div. | div. | aiv. | div. | div, 
MS lise desl cacevas 85:0 |120°7 |124°3 | 92°8 | 72-2 |122°1| 76°5| 73-1 |114°0 | 130°6 110°6 
1846.! Rasith eliaamis 6 72°5 |141°2 |104°3 | 123°3 |238-0 |181-2 |139°7 |105-9 | 88-7 | 106°6 113°3 
1847, wosabs| apenas 70°8 |102°8| 89-7 | 145-8 | 66°7 |161°2) 79°5 | 82°3| 88:9 | 126:0 |107-7 

Mean........ vessee | 76°6 |118°4 |103°1 

| | ee | 
125°7 |112°0 153-2 | 96°6 | 85°6 | 97-4} 122-1 |110°5 







