
TRANSACTIONS OF THE SECTIONS. ; 5 
responding in size to the section mn, fiz. 1, of the cone of rays CedD; and the 
conical part CDE will be represented by another halo or circle, round the halo mn, 
and corresponding to the section op of the cone of rays ELL. 
Results demonstrating the truth of these views have been obtained photographi- 
cally by my friend Mr. Buckle of Peterborough, whose beautiful Talbotypes obtained 
a Council Medal at the Great Exhibition. ‘The acting diameter of his lens was 33 
inches, and the effect of the combination of the marginal pictures is most distinctly 
exhibited. 
Let us now apply these results to the photographical pictures of the human bust 
as taken in a camera. The human face and head consist superficially of various 
’ surfaces, some vertical, some horizontal, and many inclined at all angles to the 
axis of the lens by which they are to be represented on a plane surface. A true 
perspective representaticn of the human head placed at AB, will be that which is 
given by a lens ab whose diameter is equal to that of the pupil of the eye, or as 
formed by lines passing from the centre of the pupil to different points of the 
head. From such a portrait, all surfaces, such as AC, BD, EC, ED will be 
excluded ; but if we use the whole lens LL, all these surfaces, and all those of an 
intermediate inclination between AC and EC, BD and DE, will be introduced 
into the portrait. If, for example, LL is a horizontal section of the lens, the right 
hand marginal parts of the lens, between a and L, may introduce into the portrait 
the left eye, or the left ear, or the left side of the nose, and all other parts of a certain 
inclination to the axis; thus enlarging all such parts and widening the picture. If 
LL be a vertical section of the lens, the lower part of the nose, the interior of the 
nostrils, the lower part of the upper lip, and the lower part of the chin will be intro- 
duced into the portrait by the lower marginal parts 6L of the lens; while the top 
of the head, the upper parts of the lip and the eyelids, will be introduced by the 
upper marginal parts aL of the lens. The same is true of all other sections of the 
lens, and a monstrous portrait of the human bust is thus obtained by the photo- 
grapher, the monstrosity increasing with the size of the lens. The nature and 
character of the portrait will thus vary with the superficial form of the lens, which 
may be circular, oval, square, rectangular, triangular, or of any irregular form; and 
in this way remarkable modifications of photographic portraits may be produced 
merely by varying the shape of the lens. 
The amount of the deformity introduced into portraits by a lens three or four inches 
in diameter may be readily estimated by the fact, that when a portrait is taken from 
two points two and a half inches distant, such as those taken as seen by each eye 
separately, the difference between the two is so well marked that it can be pointed 
out by a child. A portrait, therefore, consisting of a combination of portraits as 
seen from every point of a lens three or four inches in diameter, must give a form and 
expression to the human countenance very wide of the truth. 
The hideousness of photographic portraits is universally admitted, and has been 
ascribed to the imperfection of the lenses employed, the unsteadiness of the sitter, 
and the necessary constraint of features and of limb under which he submits to the 
operation. The true cause, modified doubtless by others, is the size of the lens, even 
if the lens is optically perfect. 
The photographer, therefore, who has a genuine interest in the perfection of his 
art, will receive these truths with gratitude; and by accelerating the photographic 
processes, with the aid of more sensitive materials, he will be able to make use of 
lenses of very small aperture, and thus place his art in a higher position than that 
which it has yet attained. The photographer, on the contrary, whose sordid interests 
bribe him to forswear even the truths of science, will continue to deform the youth 
and beauty that may in ignorance repair to his studio, adding scowls and wrinkles 
to the noble forms of manhood, and giving to a fresh and vigorous age the aspects 
of departing or departed life. 
But while small apertures possess such a peculiar advantage as that of giving a 
true perspective representation of the object or scene to be delineated, a small lens ~ 
possesses still greater advantages. In large lenses much light is lost by the absorp- 
tion of rays in passing through a great thickness of glass, and also by reflexion from 
the four or eight surfaces of the achromatic lens or lenses employed. In such lenses, 
too, neither the chromatic nor the spherical aberrations, which increase with the 
