46 REPORT—1862. 
ble of sustaining a successful competition with linseed cake itself, and not more 
than two-thirds the market value of the latter, it now only remained to prove that 
its practical answered to its theoretic value. Of this there did not appear to me to 
be any serious doubt; nevertheless I thought it better to the matter to the test 
of practical experiment. A friend to whom I named the subject readily entered into 
the plan of trying the effect of this cake upon a portion of his stock; the result 
roved his cattle would eat it with eagerness, and, as far as the experiment has gone, 
it has answered our highest expectations. 
On a Simple Method of taking Stereomicro-photographs. 
By Cuarius Haerscu, F.C.8., Lecturer on Chemistry at the Middlesex Hospital. 
After trying various plans, the author devised the following, which answered 
perfectly. A microscope with its eyepiece removed is placed in a horizontal posi- 
tion, and fitted to an ordinary sliding back, single lens, stereoscopic camera, Be- 
hind the object-glass is screwed an adapter, in the inside of which is a tube, which 
can be turned half round by means of a lever from the outside. Sliding in this 
tube is a second, furnished with a stop which cuts off half the pencil of light coming 
from the object-glass, in fact occupies the same place as the prism of a binocular 
microscope. The distance of this stop from each object-glass is adjusted experi- 
mentally by sliding the tube backwards and forwards till the best effect is obtained. 
The prepared plate being put in its place after carefully focusing the object, the 
first picture is taken. The plate is then shifted, the stop turned half round, and 
the second picture taken on the other half of the plate. If the object be of any 
thickness, its upper surface should be focused for one picture, and its under surface 
for the other. 
The adapter with its stop was exhibited to the meeting. 
Lowe’s Ozone Bow. By KE. J. Lown, F.R.AS. Se. 
This box has been constructed so as to ensure perfect darkness to the test-paper 
without interfering with the passage of a current of air. There are two openings 
into this cylindrical box, the one above and the other below. These openings are 
not direct into the box itself, but into narrow winding passages in the first instance ; 
they are also opposite each other. If the wind is blowing in an easterly current, 
and the upper opening is on the east side, then the air will enter the box on the 
Fig. 1. Fig. 2. 
upper half (fig. 1), will move round the circular passage until it enters the central 
cavity (A) where the test-paper is hung, afterwards passing round the lower pas- 
sage (fig. 2) in a contrary irection, and out again at the west aperture. Or if the 
wind happens to be in the opposite direction, it will enter from below and leave the 
box from above. The advantage is obvious—a current of air passes through a dark 
chamber. The box is small, and its price almost nominal, 
Observations on Ozone. By E. J. Lown, F.R.AS. $e. 
The following are results of observations made at the Beeston Observatory during 
the past four years :— 7 
Ist. If the temperature is raised, the amount of ozone will increase. 
2nd. If the current of air through the box increases in rapidity, the amount of 
ozone will increase, 
