MAGAZINE OF SCIENCE AND ART. 
101 
now be placed in a bath of a saturated solution of 
gallic acid, in distilled water — the same dish that was 
used foi sensitizing will do if careful hr washed. The 
bottle containing the solution of gallic acid must be 
quite filled and the stopper worked in, if this precaution 
be neglected the bath wi 11 soon decompose. Filter the 
solution, place the exposed paper in it and turn it over 
occasionally keeping the whole of tho sheet under the 
surface of the solution, in half an hour, or even less, tho 
picture begins to develope gradually ; after some time, 
say two or three hours, the gallic acid has no longer any 
action, and it is necessary to increase its developing 
power by tho addition of the following mixture t—pour 
off almost all tho gallic acid into a measure, and for 
every ounce add five or six drops of the sensitizing 
solution, and about the same quantity of alcohol, pour 
this on the negative, and watch carefully, removing 
it from time to time for examination, nntil the high 
lights are quite black, when the developing must be 
stopped, and the negative is ready for fixing or removing 
from the paper all tho unaffected iodide of silver 
forming in the negative the lights; a bath of G ozs. 
hyposulphite of soda to 20 ozs. of distilled water is 
poured into a dish kept for this especial use, one of 
gutta percha answers every purpose; let tho negative 
remain in this until atl the yellow iodide of silver is 
extracted, and the lights are white, because the least 
trace of yellow will materially retard the printing. 
If the negative should not he sufficiently developed by 
tho addition of the above mixture, a small quantity of 
pyrogallic acid is to be dissolved in the bath, this soon 
forces out every part of the view and often enables us 
to procure a picture, when without this treatment a 
failure would have resulted. The negative must 
now be removed into a tub or dish of clean water, 
which must be changed at least six times, and it 
should be allowed to soak at least twelve hours, so 
as to effectually remove every trace of the hypo¬ 
sulphite of *boda, which would otherwise gradually 
destroy it. After it is sufficiently washed, it can be 
removed, allowed to dry, and then must bo slightly 
warmed before a fire to melt the wax, and so free it 
from the grain of the paper. _ 
I have on several occasions succeeded in taking 
eighteen pictures in two days, having had to choose the 
sites as well, and to prove the sensibility of tho paper, 
I have seen portraits takon with waxed paper in 30 
seconds, in diffused light, with a compound lense; 
and three years back some beautiful photographs of the 
magnified sections of woods and shells, taken by this I 
process, were exhibited at tlio London Photographic j 
Society’s Annual Exhibition. I beg to offer this pro¬ 
cess to the especial attention of such amateur Photo¬ 
graphers as we may number among us, who have 
leisure time and inclination to practice the fascinating 
art of landscape photography, which enables us to take 
away from scenes we have enjoyed, not a drawing, a 
mere pencil sketch, but the scene itself, correct, even to 
a fault, and with a fidelity of detail perfectly un¬ 
approachable by hand. 
To complete this paper, I have now only to add a few 
details on my method of printing, which, though they 
may not present anything new, still as I have invariably 
found to yield good results in my hands, I think I 
ought to communicate it to the Society. I always use 
a solution of nitrate of silver of at least 50 grains per 
02 . of distil led water, keeping animal charcoal in the 
bottle, because the organic matter of the paper 
gradually darkens and thickens tho solution. Filter 
before using and carefully float the paper on the sur¬ 
face, taking care that the back is not touched by the 
bath; it may be allowed to remain in about five 
minutes, then it is raised by the forceps and hung up to 
dry—I usually attach a small piece of bibulous paper 
to drain off tbe superfluous moisture,—when quite dry 
this sensitive paper may be put into the printing or, 
more properly, tho reversing frame, and exposed to the 
direct action of the sun’s rays until the edge of tho 
paper becomes almost black, tho frame may then b8 re¬ 
moved and opened at the back to see what progress has 
been made, the exact tint at which the positive should 
be removed varies with each negative. When suffi¬ 
ciently printed it is placed in a bath of hyposulphite of 
soda of Go/, hypo, to 16 distilled water, to this is ad* 
ded 4 grains neutral chloride of gold dissolved in water, 
tho paper must be quite immersed in this bath, the 
hyposulphite soon removes the nitrato of silver in the 
liguts, su that even if the proof be over printed, in 
this bath it may be corrected; the picture quickly 
acquires a rich red tint, and passes through various 
shades, tho last of which is very much like the tone of 
a mezzotint engraving; these shades arc, however, 
affected by the amount of albumen on the paper. The 
photograph should be all owe 1 to remain in tbe hypo, 
bath at least half an hour and longer, if the desired tone 
is not obtained in that time, it must then be placed in a 
large vessel of water, which must frequently be 
changed, if any contrivance can be adopted to wash the 
proof in running water it is far preferable, when suffici¬ 
ently washed, the picture can bo removed, dried, and 
mounted. 
Waxed paper negatives do not print as fast as those 
on collodion, still by this process I have printed eight 
or nine copies from one negative in a day* I am aware 
that many methods of printing are preferred to this, but 
T never found any I have done to fade when proper at¬ 
tention has been paid to tlio washing; some of the 
specimens exhibited this evening have been done nearly 
four years, and exposed to very unfavourable circum¬ 
stances, among the most destructive of which may be 
reckoned, lying about unframed in a room where gas 
is burnt. In conclusion, I beg to state, that if any mem¬ 
ber of the Society requires farther information on the 
subject, 1 shall at all times he glad to communicate 
what I know. 
[All the apparatus and materials mentioned in this 
paper, together with illustrative views, were exhibited 
to tho Society.] 
The following paper was read on Wed¬ 
nesday, August 13th, 1856. 
THE IRON-MAKING RESOURCES OF NEW 
SOUTH WALES. 
BY J. n. THOMAS, ESQ,, C.E, 
_ The present moment—when public attention is being 
directed towards railways, and the requirements for 
I iron tor them and other extensive public works are 
rapidly increasing, and considering that for this im¬ 
portant metal, one which not only exceeds any other in 
usefulness, but all the other put together, we are de¬ 
pending upon Europe with the necessary delay of a lomr 
voyage for our supply—is a favourable opportunity of 
calling your attention to the natural resources which 
we possess witliiu the colony; and I think there is no 
fitter subject for the exercising our physical and intel¬ 
lectual powers, than in turning the gifts bestowed by 
the Great Giver of all things to the daily uses of this 
life. 
That New South Wales is not wanting in the requi • 
site raw materials for the production of a fine class of 
malleable iron has already been shown by the beautiful 
specimens which were forwarded to the late Paris Ex¬ 
hibition, and which elicited very high eneouinms from 
the scientific gentlemen forming the jury.upon that de¬ 
partment. But if more weighty argnments were re¬ 
quired, I would call your attention to the massive bars 
of wrought iron, the produce also of the cdony, which 
are before you this evening. 
Although I must confine myself in this paper to a 
description of but one manufactory of iron as yet in the 
colony, namely, the Fitz Roy works at Mittegong, at 
present in course of construction, yet, as with tlie in¬ 
creasing commercial prosperity of the country, and the 
desire to obtain the means of more rapid communication 
between its capital and vast interior, railways advance, 
it will no doubt be found that, in other places, iron and 
