My troubles began in slide painting in making a sufficiently fine outline; and this is how I overcame this difficulty, and hit upon a plan at once as good, if not better, than that given by Dal linger of drawing on ground glass with a pencil: - I first hunted up an old round table; this I painted a dead black colour, smoothing it off with sandpaper and filling up all cracks; then another coat of black, with plenty of turps in and a tew pinches of vermilion to take off any tendency to blue in the paint. When thoroughly hardened, you have a circular black-board, upon which you may sketch your intended outline. With a white chalk crayon, work as many fine outlines as you think proper. I then from this took a negative with an instanto-graph, using the 3 1/4 in. by 3 1/4 in. prepared " lantern dry plates " of Lancaster, giving about 5 seconds in dull weather, and developed until the black table began to show the merest trace of darkening; then I worked off and fixed and dried. I then had a most beautiful outline of the subject I wished, and done in J the time it would have taken me to draw on the glass direct, and far better, and shows beautifully on the screen.

Any amount of detail can be quickly done on the round black board, with the positive assurance that it will show well when magnified. (H. Green.)

Having prepared two pieces of wood - one of them having a long, tapering point, that of the other being more obtuse and of dimensions suitable for being easily held by the fingers - wrap tightly round them a small piece of thin washleather. They will then present an appearance suggestive of crayon stumps. I would recommend the beginner in this art to procure a number of good engravings of landscape, scenery having a nearly uniform sky with a few light clouds; because, if he study these, he cannot fail to acquire a good idea as to the forms of and effects produced by such clouds. It will be well for him to .practise with a pencil and a sheet of paper those forms best adapted for the special picture on which he is engaged. Having thus previously determined upon the nature of the clouds - confining himself at first to those white, fleecy ones which are so frequently seen floating across a clear blue summer sky - let him apply the larger of the stumps, and, with a motion conforming to the curling outlines of the cloud, remove the sky-paint. There is room here for great artistic display; indeed, it is nearly the only stage in the whole course of painting a photographic transparency in which artistic taste can be shown.

I have seen a transparency-artist point a common match with a penknife, wrap round it a bit of thin washleather, and in less than a minute pick out clouds in a picture which no amount of protracted labour could have improved upon. I called it "genius ": he said there was no genius in it, other than that which was the result of study and practice. In many cases the mere suggestion of a cloud proves effective. Let the upper edge be clean and sharply cut, and avoid the bad taste of bringing the cloud up near to the projecting tree or spire and then breaking it off suddenly. Carry it boldly across the projection, which quite ignore. The advantage of doing so will be found when at an after-stage the colour is removed from the spire, by which the sky is thrown back, the other being brought near. It is so easy to clean off the sky with the stump that the tyro is often tempted to overdo his clouds; hence he must be cautioned against this. I have spoken of pure white fleecy clouds; at a more advanced stage he must try to back up the silver edges of his clouds with a more materialistic colour. For this purpose a little Payne's grey, warmed with rose madder very sparingly applied, will produce a good effect.

It is not easy to impart a knowledge of cloud-making altogether by precept, so I would recommend the pupil to purchase -a few well-painted slides, and observe the special means employed to obtain such effects as are produced. The sky being completed, remove by means of the fine stump all paint from the distant hills, trees, spire, and indeed from every portion of the picture except the sky. If there are distant mountains, colour them with crimson and raw sienna, or crimson and blue, according to their nature, keeping carefully to their' outlines. Observe that no dabbing need be had recourse to when painting the rest of the picture, unless it be a subject in which there is a smooth, unbroken portion, such as a lake or the sea. As this is supposed to give a reflection of the sky, it must be painted in a similar manner. Observe, also, that every portion of the picture must be painted stronger and in brighter colours than would be the case were it a small picture which was to remain and be viewed as such, because by magnifying a 3 in. picture up to 12 ft. the colours become attenuated by the act of enlargement; therefore, the colours may be strongly applied, in the certainty of their being toned down when projected on the screen.

To return to the mountains; while the distance is warm and of a ruddy purple, keep the shadows cold, especially in the nearer ones. When painting the mountains avoid using the brush in such a way as to cause a ridge of paint to form an outline, but as far as possible work the brush from the margin inwards. By doing so the sky is left undisturbed. This also applies to trees. For these a green is employed composed of gamboge and Prussian blue. This will answer for the greater number of subjects in which there is foliage; but the addition of crimson lake will be necessary to obtain such warmth as that associated with autumnal tints. There are some specimens of foliage which may be fittingly coloured by lake and gamboge alone; but a judicious mixture of the colours mentioned will serve every purpose. It is not as if the painting were being made on clean or transparent glass. Here the foliage is composed of shades more or less dark, and, what is of importance also, of a tone that may range anywhere between a warm ruddy brown and a cold black, according to the method adopted by the photographer in toning. And this renders it impossible to say definitely what pigments ought to be employed in painting them. If the foliage be sombre , and heavy, the gamboge should then predominate.