572 
NATURE 
[OcTOBER 12, 1899 
hand corner will be noticed numerous flashes from 
clouds a great distance away. 
I will now describe three of the four photographs 
I secured during the storm that passed over Westgate- 
on-Sea, Thanet, during the night of August 5 of this | 
year (see letter, NATURE, vol. Ix. p. 391) ; all four show 
Fic. 3 —Showing bright (p and p) and dark (a and c) flashes photographed 
at Westgate-on-Sea, on August s, 1899. 
dark as well as bright flashes. The camera employed 
was one of those excellent and handy little 5 x 4 day- 
light folding Kodaks, and the exposure in each case was 
fifteen minutes. The storm, I may add, passed roughly 
from S.E. towards N.W., and my camera was placed on 
awindow-sill facing due north. 
W.J, LOCKYER 
d 1999 
Fic. 4.—Showing bright (sn and c) and dark (a) flashes photograph=2d 
at Westgate-on-Sea, on August 5, 1899. 
Fi 
flashes, 
and 
~ 
“5 
showing the north-western sky, displays several 
the most prominent of which are C and D bright 
\ and B dark. The bright flashes have no rami- 
fice cane while the dark distinct flash A has several dark. 
It may be that B is only a large ramification of A, but it 
is difficult to sz Ly. 
NO. 1563, VOL. 60] 
| 
| Fig. 3. The northern sky as here shown displays four 
| prominent flashes, A and c dark and B and D bright. 
|B, as will be noticed, appears to take a very circuitous 
path, which resembles very closely that illustrated ina 
previous number of NATURE (vol. xlil. p. 152), and which 
| was a reproduction from a photograph taken on June 6, 
1889, by Mr. Rose at Cambridge. 
| The last, and, I think, absolutely unique photograph of 
Fic 
-Enlargement of dark flash a in Fig. 4. 
a dark flash, is illustrated in Fig. 4. The negative was 
exposed when the storm was perhaps just a little north 
of my position (camera pointing due north). The two 
most prominent flashes are those marked A and B. B 
is the ordinary bright flash with numerous bright 
ramifications, while A is also equally, if not more, strong 
but dark with dark ramifications. An enlargement 
of this flash is shown in Fig. 5. Most interesting, 
