57 
waters of these currents was found to occur because of the 
small number of observations in the currents, there being 
only one, for instance, of the L’ Agulhas current, and this 
one being masked in the average of the Indian Ocean region, 
the specific gravity of part of which, as is well known, is 
reduced by the fresh water of the large Asiatic rivers. 
PHOTOGRAPHICAL SECTION. 
December 13th, 1866. 
J. Baxendell, F.B.A.S., Vice-President of the 
Section, in the Chair. 
Mr. Coote exhibited a frame for printing transparencies 
on glass, of which the following is a description : — 
As frames for printing transparencies for the lantern and 
stereoscope have occupied some little attention of late, in 
the British Journal of Photography, I thought it might be 
useful to submit to the inspection of the meeting to-night 
one that I had made last winter for printing stereo-trans- 
parencies from negatives, on plates 7 Jin. by 4 Jin., the size 
I always use on account of being able to take single pic- 
tures in the same camera. The frame is the same in prin- 
ciple as the usual frame for printing transparencies by 
superposition, and without having to cut either negative 
or print by simply moving the prepared plate and negative 
to the right and left in opposite directions alternately ; but 
it is a little longer, and 4 Jin. broad inside. The opening 
for exposure is in the centre, but is made longer than is 
required for a stereo print. Over this opening I place a 
mat made of thin brass, the desired size and shape of the 
