waxed paper generally used for larger sized plates, which is always to be found in every dark room.

The plates will be found to be very slow, far more so in fact than the generality of lantern plates; they are therefore not so suitable for reductions as for contact work. For cold black tones by contact, expose from 8 to 10 seconds with an average negative, at a distance of 1 foot from an ordinary 16 c. power gas jet, and develop with the following metol developer :

No. I

Metol, 40 gr.
Soda Sulph, 7 dr.

No. 2

Pot. Carb., 120 gr.
Pot. Bromide, 48 gr.
Water, 8 oz.

Water, 8 oz.

Use equal parts of each. The image will come up very quickly, but it will be necessary to continue development till the image is well through the back, and the front appears over developed and foggy.

For warm black tones give about the same exposure, but instead of metol use equal parts of the following Hydrokinone developer :B Soda Hydrate, 64 gr. Water, 8 oz.

A Hydrokinone, 64 gr.
Soda Sulph., 6 dr.

Pot. Brom., 12 gr.
Water, 8 oz.

For tones ranging from violet to deep brown, red, and crimson, increase the exposure in the first case to three or four minutes, and add to each ounce of above mixed developer three grains of ammonium bromide and three grains of ammonium carbonate, or for red or crimson tones expose six to ten or more minutes, and add to developer six grains each of the ammonium bromide and ammonium carbonate. By varying the exposure between these periods and also the amounts of the two chemicals added proportionately, so the resulting colours will differ. In the case of prolonged exposures the image will be a long time appearing, probably 5 minutes or more, and density will be gained very gradually.

It is better to err on the side of over development than otherwise, as if the slides are not sufficiently dense, and are intensified, the effect originally aimed at is lost, although some very nice effects may be obtained, my experience being

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that a weak slide, if full of detail, intensified with the usual mercury and soda sulphate formula will usually give a pleasing colour, but a slightly over-developed slide is preferable; reduction to what is considered the proper density being effected by means of a weak solution of hypo, to which has been added two or three drops of a solution of the red prusseate of potash; this will also clear the slight fog which the prolonged exposure and development causes, and a sparkling transparency will generally result.

If larger sizes are coated they will be found very useful for line negatives for Photo-lithography, as they are very slow, being about the speed of wet collodion, and give absolutely clear glass, and with intensification as much density as may be desired.

PROFESSOR RÖNTGEN'S X RAYS.*

In the transactions of the Physical and Medical Society of Würzburg, of Dec., 1895, Prof. Fr. C. Röntgen of that town, has published a most interesting discovery of some new rays, of which we will give an account, by reason of the extraordinary importance which it is likely to attain in many respects. A high vacuum tube, similar to the well-known Geissler tubes, and showing in a distinct manner the Cathodic rays when excited by the discharge of a Ruhmkorff Coil, was for some purpose enveloped in a case of thin black cardboard, and Prof. Röntgen observed at each discharge strong fluorescence on a paper laying close by, which was soaked in Barium-Platin Cyanide. The rays producing this phenomenon not only penetrated the cardboard covering, but also all intervening bodies, for instance a stout book of 1000 pages or some pine wood boarding of several centimetres thickness, although to a varying degree. Whilst the wooden boards at two metres distance from the vacuum tube were almost completely transparent to the rays, an alum sheet of 1.5 mm. thickness already produced a perceptible shadow on the paper, whilst a sheet of lead of equal thickness proved to be entirely opaque. These newly discovered rays are by no means identical with the Cathodic

H. THACKER,

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rays, as the latter are known to be confined within the glass
tube itself; we have therefore to deal with some special rays,
which are capable to pass through all bodies, with the
exception of some metals, more or less completely. This
transparency becomes less the thicker the medium, and is
also perceptibly influenced by the density of the medium. A
further difference is established by the absence of any
deflection of the new rays, even in a strong magnetic field:
Prof. Röntgen has meanwhile given them the name of x rays.
Similar to the fluorescent effect upon Barium-Platin cyanide
these x rays act upon other materials, notably on the phos-
phorescent compounds of calcium, on glass, rocksalt, etc.;
special importance, however, attaches to the fact that they
act upon photographic dry plates, and so permit of photo-
graphs being obtained in broad daylight, the sensitive plate
being contained within a closed dark slide. The x rays alone are
able to act through the wooden shutter, which in ordinary
photography is withdrawn during exposure. This opens up
an entirely new field to photography if the table intervening
between tube and sensitive be, for instance, a wooden box
containing a set of weights, the x rays pass clearly through
the box, but not through the metal, and the result will be a
photograph of the metallic weights alone. The most striking
results were obtained whilst Prof. Röntgen attempted to
photograph a human hand; in this case the plate after
development showed the bones of the hand, and apparently
freely suspended or floating the rings on the fingers, whilst the
fleshy part of the hand remained invisible. Meanwhile the
Physical Institute at Leipzig had repeated these experiments,
and succeeded in producing the full size photograph of a fish
8 inches in length; its shape is faintly indicated as a dark
area, showing some of the interior parts. The bladder
appeared very distinctly defined in white; above it one could
see the parallel arrangement of the bones and the distinct
impression of the spinal column; head and tail were clearly
outlined. We do not yet venture to state, whether and to
what degree this method may be perfected in order to render
the interior of the human anatomy visible, but it is to be
hoped that further research and experiments will prove suc-
cessful, and that we shall be able to realise the hopes raised in
suffering humanity.

J. HAMMERTON

& SON,

Jewellers, Engravers, Designers,

GOLD AND SILVER MEDALS AWARDED FOR JEWELLERY.

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THE JENOLAN CAVES.

ON 13th March Mr. J. H. Harvey, of Melbourne, lectured upon the above subject to a large audience, including numerous friends of members, who accepted the special invitation issued by the Association. A very fine set of slides, prepared by Mr. Harvey, and shown by the Club's lantern, rendered the evening's entertainment complete. The lecturer racily described the route taken from Sydney across the Emu Plains, over the Blue Mountains by way of the famous Zig-Zag railway. Mt. Victoria, at an elevation of 3,500 feet, being reached, the tourist exchanges seats from train to coach, thence the caves are reached by a mountain drive of 40 miles, where magnificent scenery is seen on all sides, negotiating en route various streams and gorges until the village of Jenolan is reached. We now come to the cave pictures, commencing with some of the easily accessible such as the Nettle and Arch caves, the Devil's Coach House and others, the chambers known as Lucas, Cathedral, Music Hall, Shawls, Exhibition and other caves are shown with brilliant effect. Numerous formations called Jewel Casket, Confectioner's Shop, Lot's Wife, Crystal Cities, &c., are certainly unique in interest, and the photographs obtained by Mr. Harvey, under difficulties known to all who have had any experience in cave work, are exceptionally good. The fantastic shapes into which many of the stalactites and stalagmites are twisted in some cases, should form a wide field for the speculations of our geological friends. In some of the caves the electric light has been fitted up, and the effect is perfect, the penetrating rays being specially suited to the weird regions. Leaving the caves the lecturer exhibited some views of the country surrounding the mysterious vaults and caverns towards the Kanangara Walls. A few of the beauties of the bush track on the return, including camps, &c., were shown, and upon concluding his reminiscences of the holiday trip Mr. Harvey received the heartiest thanks of the meeting which were conveyed to him by the chairman, Mr. J. B. Leitch.

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LITTLE RYRIE ST., GEELONG. Badges, Gold & Silver Jewellery in stock, or made to order.

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SKETCHING CLUB AND ART SOCIETY..

MEETINGS HELD DURING THE QUARTER.

7/3/96. Good attendance. The work exhibited denoted that the artists fully recognised the chief aim of the Society, viz., to encourage members to work direct from nature. The result of this was that many of the sketches showed a truth of tone and colour which are too frequently lost in the elaborately finished painting. The following ladies and gentlemen were represented :-Miss Chassie Cole, two sketches on the Yarra at Abbotsford, and two from Barwon Heads; Miss L. Davey, two scenes on Moorabool River; Mr. A. Ramage, water colour sketches Corio Bay; and Mr. M. Gough, an "interior" and an afternoon effect on the Barwon River. Criticisms upon the several studies were freely indulged in by members.

21/3/96. Attendance large. Musical and Refreshment Committees were appointed for a social to be held at an early date, when an exhibition of work will also be provided, and it was resolved that the Hanging Committee should rigidly enforce the rule which excludes work not taken from nature. At the close of the formal business, sketches taken since last meeting were exhibited, and from the number and variety of subjects it was evident that members were determined to maintain the growing reputation of the club. The following are the names of exhibitors and their work submitted:-Miss Cole, "Grey Day, Fitzroy Gardens," and "Surf at Spring Creek"; Miss Davey, "Beach, Barwon Heads," and "Evening Effect on the Moorabool River "; Miss Wilkins, "Calm before the Storm, Corio Bay," and "Our Eastern Slopes"; Mr. F. Monteath, two scenes near Healesville, "Fine Afternoon on the Barwon River," and "View of Geelong"; Mr. A. Ramage, "Peaceful Barwon" and "Breakers, Bream Creek"; Mr. M. Gough, "A Country Drive," "Warm Afternoon," and "Twilight." The whole of the work was subjected to the keenest criticism, and arrangements were made for systematic study during the coming month.

JOHN BUCHANAN,

Sail, Tent, Tilt, and Tarpaulin Maker, MOORABOOL ST., GEELONG.

THE OLD SHOP.