The first of the composites exhibited on this occasion is made by conveying the images of three separate portraits by means of three separate magic-lanterns upon the same screen.  The stands on which the lanterns are mounted have been arranged to allow of nice adjustment.  The composite about to be shown is one that strains the powers of the process somewhat too severely, the portraits combined being those of two brothers and their sister, who have not even been photographed in precisely the same attitudes.  Nevertheless, the result is seen to be the production of a face, neither male nor female, but more regular and handsome than any of the component portraits, and in which the common family traits are clearly marked.  Ghosts of portions of male and female attire, due to the peculiarities of the separate portraits, are seen about and around the composite, but they are not sufficiently vivid to distract the attention.  If the number of combined portraits had been large, these ghostly accessories would have become too faint to be visible.

The next step is to compare this portrait of two brothers and their sister which has been composed by optical means before the eyes of the audience, and concerning the truthfulness of which there can be no doubt, with a photographic composite of the same group.  The latter is now placed in a fourth magic-lantern with a brighter light behind it, and its image is thrown on the screen by the side of the composite produced by direct optical superposition.  It will be observed that the two processes lead to almost exactly the same result, and therefore the fairness of the photographic process may be taken for granted.  However, two other comparisons will be made for the sake of verification, namely, between the optical and photographic composites of two children, and again between those of two Roman contadini.

The composite portraits that will next be exhibited are made by the photographic process, and it will now be understood that they are truly composite, notwithstanding their definition and apparent individuality.  Attention is, however, first directed to a convenient instrument not more than 18 inches in length, which is, in fact, a photographic camera with six converging lenses and an attached screen, on which six pictures can be adjusted and brilliantly illuminated by artificial light.  The effect of their optical combination can thus be easily studied; any errors of adjustment can be rectified, and the composite may be photographed at once.

It must not be supposed that any one of the components fails to leave its due trace in the photographic composite, much less in the optical one.  In order to allay misgivings on the subject, a small apparatus is laid on the table together with some of the results obtained by it.  It is a cardboard frame, with a spring shutter closing an aperture of the size of a wafer, that springs open on the pressure of a finger, and shuts again as suddenly when the pressure is withdrawn.