292 
rOPULAR SCIENCE REVIEW. 
universal employment of albumenized paper appears likely to suffer a 
severe check by the introduction of the resinized surfaces of Mr. Cooper. 
Several formula; have been announced in which as many different gum- 
resins have been selected to fulfil the object in view. It is scarcely pro- 
bable that the details of the new process should already be incapable of 
improvement. Gum benzoin was first used, but the recommendation at 
present is in favour of the employment of a mixture of frankincense and 
Cliio turpentine — one ounce of the former and one drachm of the latter 
being dissolved in half a pint, or rather less, of methylated spirits of wine, 
with the addition of two drachms either of the chloride of cadmium or zinc, 
to furnish the necessary element for the formation of chloride of silver. 
The resin-paper is prepared merely by immersing in this alcoholic solution 
for about five minutes the papier Saxe or Rives, gradually lifting and 
removing the sheets, draining, and drying rapidly before a fire ; they are 
made sensitive by floating on a solution of nitrate of silver (sixty grains 
or upwards to the ounce of water), and when dry are ready for the 
printing-frame. It is necessary to print deeply in order to allow for a 
considerable loss of vigour always experienced in the after processes of 
fixing and washing. The specimens which have been exhibited as the 
results of this process justify the hope that we shall shortly be placed in 
possession of a system of photography by which more artistic effects may 
be produced with greater ultimate security upon the score of permanence. 
We may judge of the commercial success which has attended the opera- 
tions of the Contractors for Photography at the International Exhibition, 
by the announcement made by Mr. England in reference to the quantities 
of paper and chemicals used during the busy period of six months that the 
Exhibition building has continued open to the public. The sale of photo- 
graphs is not likely, however, to be restricted to the quarter of a million 
stereoscopic slides already disposed of. The materials used amount in 
round numbers to the following : — 
White of egg 200 gallons. 
Paper 70 reams. 
Nitrate of silver 2,500 ounces. 
Metallic gold 35 ounces. 
Hyposulphate of soda 25 cwt. 
Among the novelties in apparatus may be mentioned the beautifully 
moulded glass dishes of Messrs. Chance, intended specially to hold the 
nitrate of silver, a corrosive agent which the ordinary glaze upon earthen- 
ware is not well able to withstand. The “ Patent Ebonite” baths and 
other apparatus, manufactured by Messrs. Silver and Company, are, on 
account of their lightness and portability, exceedingly well adapted to the 
wants of the photographic tourist. They are made of india-rubber 
hardened by exposure to a higher temperature than that usually employed 
in the process of vulcanization ; the material is consequently unaffected 
by boiling water, and although sufficiently elastic, is yet firm and rigid. 
It can be moulded almost to any shape, takes a beautiful polish, and is 
so light that an ebonite bath complete, with dipper, air-tight cover, and 
damp-screws, weighs considerably less than the silver solution contained 
