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“ Castle Ashby Ponds,” produced in platinum, being ex tremely good; but being the work of a member of Committee, it is not for competition. WINTER PHOTOGRAPHY. BY W. D. VALENTINS. Although the introduction of gelatine plates has materially simplified the production of negatives in this department of landscape work, hitherto I have failed to obtain, by their use, the brilliancy in the high-lights and softness in shadow formerly secured by the use of wet collodion. Still, looking at the enormous difficulties to be overcome in getting clean work—such as the liability of the plate to freeze, &c., not to speak of the personal discomfort of working with water at a low temperature—the photographer of to-day has little reason to regret that wet collodion is now a thing of the past. Snow pictures are, to a certain extent, a mis nomer ; you have to get for the foundation of the picture a fall of snow, but the most beautiful effects are secured when the ground is thus covered, and a strong hoar-frost follows. Sun-light is an absolute necessity. As to subjects suitable for snow pictures, they are varied and numerous, and one need not go far to find them. The magic touch of “hoar frost” will transform a most prosaic town garden into fairyland. Trees are par excellence the most fascinating, but hardly anything comes amiss. A country lane with hedge-rows and occasional trees, the low rays of the winter sun alternating with the shadows cast by them, bearing in mind to introduce in the foreground, or where the eye may be led to it, some patch of fuz or withered grass stems, now transformed into a bewildering loveliness of silver tracery and bending spears; a wayside cottage, its thatch roof gleaming with icicles, and its probably rather ugly surroundingsnow changed into things of beauty. My way of securing these pictures, when snow and hoar frost are favourable, is as follows :—I get a dog cart, drive a few miles out of town, stopping where I see a suitable subject. It is almost impossible to select your picture beforehand. I prefer a rather slow plate, with a dense film My experience as to exposure is that it should be a quarter less than for the same subject in early spring. As to lens, I prefer a single landscape one, taking the precaution, before leaving home, to unscrew the lens and slightly moisten it with glycerine, which entirely prevents condensa tion. Most of my snow pictures have been developed with the sulphite of soda pyro developer, but I fancy any formul one is accustomed to use will do equally well. In develop ment, caution has to be exarcised that it is carried far enough, the appearance of density in these pictures being most deceptive. Lastly, as to printin?, I have tried platinotype and silver ; the first I do not like for these subjects. I find white albumenised paper to give the best effect. In conclusion, I would commend both amateur and pro fessional photographers to lose none of the few opportuni ties we have in this country to secure, in the shape of negatives, the beautiful effects to be obtained during a hoar frost. The former will add to his collection most unique and lovely pictures : and the latter, when getting the same, will find them remunerative. HOWTO PHOTOGRAPH MICROSCOPIC OBJECTS BY I. H. JENNINGS. Lesson XL—Preparing Sections of Hard Substances for Photography. Many of the sections of hard substances, such as bone, rock, &c., sold in the shops, are too thick. Those pre pared by the best lapidaries cannot be excelled ; and if the Student can afford to pay the high price charged for making these sections—from 2s. to 2s. Gd. each—he is advised not to undertake the labour and trouble of pre paring them himself. For, although the manipulator may be skilful and patient, even when a machine is used, cutting sections of rocks is both tedious and laborious. There are many excellent machines in the market specially devised for cutting sections; but they are all more or less expensive, and good work may be done by using very simple appliances, which we shall now proceed to mention. In the first place, procure an iron plate, preferably cast iron, about twelve inches square, and as thick as can be obtained. Next, a Water-of-Ayr stone, and one of harder texture, such as a Washita stone. These may be obtained at any tool-shop. A Turkey stone is very good for sections of bone. For grinding down rocks, emery of various degrees of fineness will be required —buy one pound of medium coarse, one pound of medium fine, and one pound of flour emery. To grind down a rock section, proceed as follows. Make a chip with a hammer, about one inch square, and not more than one-eighth inch thick. Sedimentary rocks, such as limestones, may be thicker. Rub down the chip with coarse emery and water on the iron plate, until one side is perfectly fiat. Remove the scratches by next rubbing the chip on a piece of plate-glass with fine emery, and then polish with water on the Water-of-Ayr stone; when quite smooth, wash it well, and let it dry. Mean time put some old, hard balsam on a glass slip, and warm it over a lamp until all the more volatile parts of the balsam evaporate, so that, on cooling, it becomes hard and tough. Don’t boil the balsam, and don't continue the heat too long. When the balsam is properly hard, heat the chip on a metal plate, rub over it a little turpentine, and re melt the balsam ; lower one end of the chip slowly into the balsam, and press it down close to the glass slip. When the balsam is cold, rub down the chip on the iron plate with coarse emery until too thin to bear further friction. Very hard rocks may be brought down to the requisite thinness on the iron plate alone, and will only require a little polishing on a stone to remove the deeper scratches. Sections intended for photography should be cut down to the extreme of thinness, and all sections should be cut thin enough to read through when placed on the page of a book. When the section becomes too thin to bear any longer the friction of the coarse emery, wash it well, and grind it thinner on the glass plate with fine emery, and finish off on the Water-of-Ayr stone. If the section is strong enougi to bear it, it should be removed from the slip on which it has been ground, and mounted on a clean slip. Warm the slide over the lamp sufficiently to melt the balsam, and push the section off with a needle into a cup of turpentine, and wash it care fully with a small soft brush. Now pour a little balsam and benzol on the clean slip, put the section upon it, add a little more balsam, and cover with a circle or square of thin glass. Sections of bone or horn must be first cut with a fine saw, and ground down in the same way, only no emery must be used, and the iron plate will not be required, as the Water-of-Ayrand Washita stoneswill prove sufficient. Before such sections are mounted, they should be soaked for a day or two in balsam and benzol to render them perfectly transparent. Sections of soft rocks, and sedimentary rocks generally, are prepared and mounted in the same way, only no emery must be used, or it will imbed itself in the section ami cause false appearances under the microscope. Most sedi mentary rocks can be finished on the Water-of-Ayr stone. Some very friable rocks, or substances such as boiler in crustations, which readily disintegrate on the grinding stone, must first undergo a preliminary hardening. Two hardening solutions are generally made use of—balsam and benzole or a solution of shellac in alcohol. The latter is much the better of the two. The solution should be quite