166 
A. W. CLAYDEN-APPLICATION OF 
thunderstorm occurs at night. Fix the camera by an open 
window (for Mr. Whipple, of Kew Observatory, has shown that 
the glass might give a double image), turn it in the direction in 
which flashes seem frequent, take off the cap, and wait until a 
flash has crossed the field of view, and then change the plate. Those 
who have two cameras might do useful work by keeping one in 
motion while the other was fixed, in the hope of getting another 
photograph like Dr. Hoffert’s, with its fellow taken in the fixed 
camera. 
In lightning-photography I believe there is a wide field for 
research, hut what I have said as to the necessity of recording the 
conditions under which cloud-photographs are taken applies even 
more strongly to lightning. The remarks on focus also apply, for 
it is practically impossible to focus on the flashes themselves. 
In all photographs it is desirable if possible to include a part of 
something fixed, such as the top of a flag-pole, a chimney, or a 
church spire. Such an object gives a point of reference which is 
especially useful when cloud-changes are represented. But besides 
this, something should be introduced whenever possible to serve as 
a rough scale. Photographs of snow-drifts and the like may be 
rendered absolutely useless by the absence of any such scale. 
Again, other subjects, such as hoar-frost, and damage by light¬ 
ning, should not only be photographed so as to give a general 
view, but the details should be brought out in other pictures so as 
to show as far as possible all that can be seen. 
I cannot help feeling that I have given only a scanty outline ’of 
our aim and desires. Nevertheless I do hope that some members 
of the Hertfordshire Natural History Society may be induced to 
co-operate with ns. We do not in the least degree wish to turn 
any one aside from the pleasant search after all that is beautiful 
or strange or rare, but only to point out new objects full of beauty 
and of great interest, and to ask for copies of photographs of 
them.* 
I shall always he most willing to give any explanation or other 
assistance in my power to all who are ready to co-operate in the 
advancement of meteorological science by means of photography. 
The instructions of the Committee are appended. 
* Prints, which may he mounted or unmounted, should be sent to me at 
Warleigh, Tulse Hill Park, London, S.W. 
