78 MEMORANDA. 
place (in an open frame) the instant before the impression is 
taken. With the arrangements employed, I may state it to 
be the most luxurious mode of taking photographs that I 
have practised—bath, developers, plates, &c., all being close 
to hand, so that there is no occasion to stir one step from 
your position. A pane of yellow glass is let into the shutter, 
above the microscope, to furnish light for manipulation. Also, 
during these experiments, I found that a pair of pictures, 
each taken with a right and left-handed illumination alone, 
was sufficient to bring an object up into relief in the stereo- 
scope, particularly when objectives of large aperture were 
employed. As micro-photography and stereography are again 
the subject of attention, I allude to these circumstances, be- 
cause they have either been lost sight of or revived as new 
facts —F. H. WENHAM. 
On the seat of the Colouring Matter in Flowers.— M. F. 
Hildebrand’s observations* on the forms under which various 
colouring matters are found in flowers, and their distribution 
in the tissue of the several organs, warrant the following 
general conclusions :—(1) That the colour of flowers is in con- 
stant connection with the cell contents, never with the walls 
of cells. (2) Blue, violet, rose, and (if there be no yellow in the 
flower) deep red, are due, with little exception, to a cell-fluid 
of corresponding colour. (8) Yellow, orange, and green, are 
usually associated with solid granular or vesicular substances 
in the cells. (4) Brown or gray, and, in many cases, bright 
red and orange (apparently uniform to the unaided eye) are 
found to be compounded of other colours, as yellow, green, or 
orange, with violet, or green and red; bright red and orange 
in like manner of blue-red with yellow or orange. (5) Black, 
excepting in the Bean, is due to a very deeply-coloured cell- 
fluid. (6) All the cells of an organ are rarely uniformly 
coloured. (7) The colour usually resides in one or in a few 
of the outer layers of cells. (8) The coloured cells are but 
exceptionally covered by a layer of uncoloured ones. (9) 
Combinations of colour are occasioned by diversely-coloured 
matters in the same or in adjacent cells (‘ Nat. Hist. Rey.,’ 
vol. 11, No. 8, p. 438). 
Kelner’s Orthoscopic Eyepiece.—Permit me to direct the 
attention of your readers to the new form of eyepiece lately 
brought out by Ross, ‘ Kelner’s Orthoscopic.’ The advantages 
which it possesses over the old Huyghenian eyepiece are 
* Contained in Pringsheim’s ‘ Jahrb.,’ iii, p. 50. 
