186 REPORT—1849. 
thunder ; numerous other oscillations occurred with thunder, and rain falling 
in torrents. 
(¢*) September 10, 1843.—We have here a well-marked instance of the re- 
gular diurnal march being interrupted by the passage of a cloud in the im- 
mediate neighbourhood of the observatory. No rain appears to have fallen, 
yet the instruments were thrown into a state of oscillation, positive to negative, 
which gradually diminished as the cloud passed off ; a spark or sparks 0°4 inch 
in length were registered. This cloud appears to have been a cumulo-stratus ; 
for at Greenwich at 3 p.m. cwmulo-siratus is registered, and during the suc- 
ceeding twenty minutes a very heavy shower of rain accompanied with thunder 
is recorded. The electrical instruments were not affected. 
(2) October 2, 1843.—The connexion in this instance between the heavy 
rain and negative charge is very apparent, and would, combined with the 
observation, of September 10, greatly tend to refer the production of the 
charge to the particular cloud by the agency of which the rain was precipi- 
tated, rather than to the rain itself. Cirro-stratus was registered at Green- 
wich from 98 20™ a.m. to 5" 20™ p.m. The violent squall of rain occurred 
there at 5 minutes before 11 A.M. 
(*) October 12, 1843.—* Front sunrise until about 11 a.m. dull and cloudy. 
At about 1] A.m. a heavy rain began and continued until about 12 15™ p.m. 
At its commencement Volta stood at 25° pos.: immediately afterwards the 
charge became negative, the maximum of which was 30° of Henley, anda 
negative state continued until about 2"45™ p.m. ‘The positive charge then 
remained during the rest of the day. The negative state existed about 
1 hour and 30 minutes after the rain had ceased; and the weather during 
this period was fine and accompanied with sunshine. The duration of the 
negative state of the conductor, viz. about 3 hours 45 minutes, from about 
1] a.m. to 2"45™ p.m., one hour and a half of which time elapsed without 
rain, is I believe a rare occurrence, and one which I do not recollect to have 
observed in my former experiments.—[F. R.]” 
The negative state of the conductor during the three half-hours is remark- 
able. It appears the sun was shining and the weather fine; but the register 
does not inform us whether clouds were present or not. On turning to the 
Greenwich observations we find rain recorded at 11" 20™ a.m., and at 1» 20™ 
p.m. thin rain falling ; the rain appears to have ceased earlier than this at 
Kew. From 94 20™ a.m. until 75 20™ p.m. cirro-stratus was registered at 
Greenwich ; and as this cloud frequently manifests itself in the form of a 
thin but very extensive stratum, it is not unlikely that it was the source of the 
negative charge observed. —[W. R. B.] 
(£) October 28, 1843.—At 3" 20™ p.m. this squall was observed at Green- 
wich without the hail. The observer thus writes: “At present there isa 
violent squall: the rain is falling in large drops: the sky is covered with a 
nimbus: a few minutes since a cumulo-stratus with coloured edges was in — 
the west, and scud was passing quickly from the west with a fine blue sky — 
between.” The head of the galvanometer needle deviated towards A 5°. 
(8) January 31, 1844.—The electrical phenomena of this day being parti- — 
cularly interesting, and well-marked both at Kew and Greenwich, we cannot 
do better than present the reader with the records at both observatories. 

Kew. 
First Storm.—At sunrise fine, but cloudy. At 8°45™ a.m. a heavy storm 
of snow and hail began, when Volta stood at 35% pos. The charge im- 
mediately changed to neg., in the maximum of which charge the Henley 
vibrated above 90°, and a stream of fire one inch long flowed from the con- 

