SCIENTIFIC SUMMARY. 
107 
present time been forthcoming. Doubts have therefore been publicly ex- 
pressed as to its practical value. We have now reason for believing that the de- 
lay arose in each such case from Mr. Woodbury’s desire to effect contemplated 
improvements before issuing other prints to the public, and which improve- 
ments have but recently been accomplished. The difficulty experienced of 
obtaining labourers sufficiently skilled to ensure the production of a large 
number of prints, possessing uniform excellence, has been overcome by substi- 
tuting metal rollers for flat plates and causing them to revolve rapidly with a 
self-inking arrangement. Thus mechanical means do perfectly that wherein 
hand-labour had not proved satisfactory, and the prints are produced with a 
rapidity and certainty such as we obtain with the type-printing cylinder used 
in calico and newspaper printing. Another proj ected improvement is that 
of substituting ink of the kind used in ordinary printing for the pigmented 
gelatine, and this improvement, which we believe to be of vital importance, 
is, we are told, in a fair way of being accomplished. Several new applica- 
tions of this important process have also been discovered. One is that of 
printing photographs on glass to serve as transparencies, etc. for decorative 
purposes, and for exhibition as magic-lantern slides ; and others exist for 
transferring the photograph to wood, stone, ivory, or metal. It is also used 
for producing permanent cartes de visite at the very moderate cost of 9s. per 
hundred, after an outlay of twelve shillings for the metal intaglio. Attempts 
have been made to blend this process with that of chromo-lithography, but 
judging by the dull, flat, horny-looking specimen shown at the South Lon- 
don Photographic Society, a very slight degree of success has attended it, 
although some ill-advised speculator has, we understand, made such appli- 
cation the subject of a fresh patent. The process patented is, first, that 
of transferring the photograph to the lithographic stone ; secondly, that of 
printing it in colours in the usual way ; and thirdly, that of printing the 
photograph again over the coloured impression by the Woodbury process. 
The small value of the patent, and the objections to such a tedious inartistic 
roundabout process, are too palpable to need pointing out. 
Another New (?) Lens. — Mr. J. Traill Taylor, a gentleman who has intro- 
duced many valuable practical suggestions and improvements in a peculiarly 
quiet unostentatious way, in the April of 1864 read, before the Photographic 
Society of Scotland, an optical paper, in the course of which he pointed out 
how, by altering the arrangement of Petzval’s compound orthoscopic lens, 
the depth of its defining power could be very largely increased, in combina- 
tion with a large field flat without a diaphragm. The only sacrifice made 
in this case was that of the microscopical degree of sharpness, which artists 
call hardness, and which gives photographs, more particularly when stereo- 
scopic, that strangely unnatural and rigid appearance which is more sugges- 
tive of metal casts than of natural effect. This paper was duly published, 
and in photographic pages ; but those critics who have no way of judging 
the value or merit of an invention but by what the inventor may please to 
claim for it himself, gave the discovery no good word, and so it speedily 
passed from their remembrance. But at the last meeting of the u London 
Photographic Society,” the same improvement, effected by identically the 
same means, viz. the introduction of spherical aberration, was again brought 
forward by an optician, who awarded the merit of its discovery to a gentle- 
