SCIENTIFIC SUMMARY. 
327 
of the Photographic Society now contains only the transactions of that body, 
and is only published when a meeting of the Society is held, or eight times 
a year. Several of the foreign journals live, for the most part, on the 
English ones; the once original Humphrey’s Journal (New York) is pro- 
bably the most noted specimen of this class. 
Permanence of Photographs in Asphaltum. — The durability of photographs 
obtained by the Pouncy process has been called in question. The process is 
based on the fact that bitumen of Judea, when dissolved in a suitable 
menstruum and applied to paper or any other surface, is rendered insoluble 
in proportion to its exposure to light. This property of asphaltum has been 
long known, but Mr. Pouncy mixes with it printers’ ink ; hence when the 
photograph is developed by turpentine the blacks are composed of printers’ 
ink and bitumen. The question that arose is this — Seeing that bitumen is 
regarded by artists with very great aversion on account of its notorious bad 
qualities as a permanent pigment, will not its presence in the blacks of 
Pouacy’s photographs be also objectionable? To this Mr. Pouncy replies, 
in effect, that the blacks or body of his pictures are not formed of bitumen 
alone, but of printers’ ink mixed with it ; that only the merest trace of 
bitumen is present in them, and that this portion is so altered by light as to 
have become incapable of 11 running” or cracking — the objections urged 
against bitumen when used as a pigment by the painters. 
Negatives on Paper . — An effort is being made to reintroduce the taking of 
negatives on paper instead of on glass. A peripatetic photographer who 
desires to obtain — say — fifty views while on his travels will find an 
astounding difference in weight between fifty stout plates of glass, twelve or 
eighteen inches in dimensions, and the same number of leaves of paper the 
same size. Why paper should not be more used for negative purposes than 
it is we cannot say. The negative is taken upon, not in, the glass plate, and 
one would think that the same sensitive coating that is applied to the glass 
might also be applied to the paper. If this can be done successfully, which, 
from experiments now in course of being made and recorded, appears to be 
the case, then will a very great advance indeed have been made in photo- 
graphy as applied to the resources of the traveller. 
New Salting Agent for Paper. — Some French photographers are recom- 
mending chloride of aluminium for salting paper instead of the chlorides of 
sodium and ammonium generally used at present. The chief advantage of 
using this salt appears to be that the image is retained well on the surface, 
and that consequently the details in the shadows of the print are better 
rendered. 
Niepce de St. Victor. — Photographic science has received a sad loss by the 
death of M. Niepce de St. Victor, which occurred on April 7, after a few 
minutes’ illness. He was seventy-tw'o years of age. To him we owe very 
much indeed, including photography on glass plates, and printing upon 
albumenised paper. From 1847 to 1862 he presented to the Academy of 
Sciences in Paris no fewer than twenty-six mimoires, the subjects of which 
were chiefly photography on glass, photographic engraving, and helio- 
chromy. His family being left unprovided for, photographers throughout 
Europe are making a subscription for them. 
