REPORT OF MR. W. J. STILLMAN.
359
since the opening of the Exhibition a still farther improvement, in the substitution of gelatine for collodion in the preparation of dry plates, has been announced, and presented with such success as to leave no doubt of its finally superseding collodion for this purpose.
In the important department of the apparatus requisite for photography, there was little to represent the actual state of either optical construction or the portable appliances "which have been carried to so high a perfection, especially in England. A single case of the work of George Hare, of London, is beyond any question the finest display of common workmanship and general good construction that was sent, and fully sustained the maker’s reputation as the manufacturer of the best apparatus of this kind in the world; but from the English opticians now at the head of the trade, even considering the great continental celebrities, Steinheil and Voightlander, there is no contribution. No representation oT photographic optics could to-day be given which would not put in the first place the admirable rectilinear lenses of Ross and Dallmeyer, of London, which, especially for scientific purposes, where correction to perfect rectiline- arity of the photographic image is necessary, are incomparable ; and have long been recognized as such even by the continental photographers, who are by their aid enabled to give architectural views free from the curvilinear distortions formerly always present in this class of work, and which were consequent on the use of the old view lenses.
A complete apparatus for microscopic photography, by Haack of Vienna, was a most admirable piece of construction, and showed proofs of enlargements to four hundred diameters, with admirable definition and flatness of field.
But in that which is after all the immediate object of the most arduous study on the part of investigators in photographic reproduction, the printing processes, properly so called, that is, those in which the image is transferred to a surface capable of producing impressions as from a block, stone or plate, the Exhibition contained but little, though that little is full of magnificent promise.
While all the negative processes by which the first impression from nature is received depend on the action of light