102 
POPULAR SCIENCE RETIEW. 
On the Structure of the Stems of the Arborescent Lycopodiaceas of the 
Coal-Measures. By W. Carruthers, F.L.S. Illustrated. — On the 
Development of the Ovum of the Pike. By E. B. Truman. Illustrated. 
— On the Structure of the Stems of the Arborescent Lycopodlacea? of 
the Coal-Measures. Part II. Illustrated. By W. Carruthers, F.L.S., 
F.G.S., Botanical Department, British Museum.— Experiments on 
Spontaneous Generation. By Edward Parfit, Curator of the Devon 
and Exeter Institution. Illustrated. — Further Be marks on the Nineteen- 
Band Test-Plate of Nobert, and on Immersion Lenses. By Colonel 
Woodward.— On High-Power Definition, with Illustrative Examples. 
By G. W. Royston-Pigott, M.A., M.D. — On the Presence of Fora- 
minifera in Mineral Veins. By Charles Moore. — On the Relations of 
the Ciliary Muscle to the Eye of Birds. By Henry Lawson, M.D. 
Illustrated. — The Histology of the Eye. By John Whitaker Hulke, 
F.R.S., F.R.C.S., Assistant-Surgeon to the Middlesex Hospital, and 
Surgeon to the Royal London Ophthalmic Hospital. Illustrated. — On 
Collecting and Mounting Entomostraca. By J. G. Tatem.— My Expe- 
rience in the Use of Microscopes. By Dr. H. Hagen. — Further Remarks 
on the Plumules of Battledore Scales of some of the Lepidoptera. 
With 3 plates. By John Watson. — The Development of Organisms 
in Organic Infusions. By C. T. Staniland Wake, F.A.L.S. 
We would especially call attention to Dr. Pigott’s paper, because, if its 
views are correct, it opens up quite a new period in microscopy, in alleging 
that even our best objectives are imperfectly constructed for spherical obser- 
vation. 
PHOTOGRAPHY. 
A new Artificial Light for Photographic Enlargements . — The production 
of large photographs of a size suitable for suspension on the wall, either in 
their uncoloured state or after they have been worked upon in crayons or oil 
colours, has for a considerable time received much consideration from photo- 
graphers. When an attempt is made to produce a very large portrait direct 
from the sitter, so numerous are the difficulties that supervene, that very 
rarely indeed is the effort crowned with success. All the difficulties of 
focus, projection, and manipulation are happily got rid of by taking a small 
negative, carte de visite size, and placing it into a solar camera or a magic 
lantern to be u enlarged/’ which it may be in a very satisfactory manner when 
the light is powerful and the enlarged image is thrown upon a sensitive 
sheet of paper instead of the usual screen. 
As the solar light cannot be relied upon, it becomes a matter of importance 
to secure the best possible artificial light. The lime light is very steady 
and its brilliancy is undoubted, but unfortunately its actinic value is low. 
Magnesium, on the other hand, does not yield a steady light, but its actinic 
power is very great. Within the past two months Dr. Van Monckhoven has 
bwn demonstrating before some of the photographic societies, and among 
others that of London, the possibility of uniting in one light the good 
qualities of both the lime and the magnesium lights. This union he effects 
