20 Mr. W. Saville-Kent on 
taken in triplicate through a set of coloured screens similar to 
that which I now exhibit, and which is in point of fact the one 
with which I originally took several hundred negatives for the 
composition of positives or kromograms for illustration in the Ives 
kromskop. This set of screens is, as you will see, tinted 
respectively red, green, and blue-violet, and the positives printed 
from the three consecutive negatives taken have in corresponding 
order to be printed in or stained the complementary tints of 
blue, red, and yellow, and are then carefully superimposed to 
produce the natural colour replica. This reversal of the printing 
colours as compared with those of the original negative screens 
will suggest itself as being a rational and consistent outcome of 
the principles that obtain in the practice of ordinary photo- 
graphy; the black of the negative being rendered white in the 
positive, and the white of the negative by black. In like manner 
the negative taken through the red screen has to be printed blue 
because that colour represents the combined tints of the solar 
spectrum minus red, which must be omitted; the red, or more 
correctly pink, print from the green screen similarly represents 
all the spectrum tints minus green, and the yellow prints from 
the blue-violet screen the spectrum tints minus blue-violet. 
The slides which I will now throw upon the screen will, I 
trust, fulfil their object of demonstrating the practical utility of 
this process for the correct delineation of, or, I should perhaps 
say, counterfeiting, the natural aspect of the objects photographed. — 
Yet more perfected results can and will no doubt be accomplished 
by further experiment and experience along this same line of 
research, and I shall be very pleased if what I am about to 
submit to you may encourage many here present to take up this 
same fascinating branch of photography. 
Mr. Saville-Kent then proceeded to the exhibition on the 
screen of an extensive series of subjects that he had prepared on 
the system he advocated. These included representative lantern 
slides illustrating all the leading natural history branches. 
Among floral subjects, the orchid class was largely to the fore, 
various species of Dendrobium, Masdevallia, Cypripedium, and 
Cattleya being especially noteworthy. Various tropical butterflies, 
suitably associated with the orchids indigenous to their corre- 
sponding districts, were included in this series. More ordinary 
floral types included a bright crimson Glowinia associated with a 
brilliant blue Morpho butterfly; a vase of lilac, and several 
groups of tropical water-lilies. Of abnormal plant forms, two 
typical species of the genus Stapelia, or so-called carrion flowers 
of South Africa—the one, S. variegata, resembling a spotted 
starfish, and the other, S. psomaensis, clothed with brown fur-like 
hair, were of special interest. It was explained by Mr. Saville- 
Kent that the carrion-like odour of these flowers attracted flies, 
