ally the equal traces left by every member of a
moderately-sized group can be made out by careful inspection; but it
is hardly possible to do this in the pictures in the Plate, except
in a good light and in a very few of the cases. On the other hand,
the larger pictures do not contain more detail of value than the
smaller ones.

DESCRIPTION OF THE COMPOSITES.

The medallion of Alexander the Great was made by combining the
images of six different medals, with a view of obtaining the type of
features that the makers of those medals concurred in desiring to
ascribe to him. The originals were kindly selected for me by Mr. R.
Stuart Poole from the collection in the British Museum. This
composite was one of the first I ever made, and is printed together
with its six components in the _Journal of the Royal Institution_,
in illustration of a lecture I gave there in April 1879. It seems to
me that it is possible on this principle to obtain a truer likeness
of a man than in any other way. Every artist makes mistakes; but by
combining the conscientious works of many artists, their separate
mistakes disappear, and what is common to all of their works remains.
So as regards different photographs of the same person, those
accidental momentary expressions are got rid of, which an ordinary
photograph made by a brief exposure cannot help recording. On the
other hand, any happy sudden trait of expression is lost. The
composite gives the features in repose.

The next pair of composites (full face and profile) on the Plate has
not been published before. The interest of the pair lies chiefly in
their having been made from only two components, and they show how
curiously even two faces that have a moderate family likeness will
blend into a single one. That neither of these predominated in the
present case will be learned from the following letter by the father
of the ladies, who is himself a photographer:--

"I am exceedingly obliged for the very curious and interesting
composite portraits of my two children. Knowing the faces so well,
it caused me quite a surprise when I opened your letter. I put one
of the full faces on the table for the mother to pick up casually.
She said, 'When did you do this portrait of A? how _like_ she is to B!
Or _is_ it B? I never thought they were so like before.' It has
puzzled several people to say whether the profile was intended for A
or B. Then I tried one of them on a friend who has not seen the
gi