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JaxUAnY 9, 1885 ] THE PHOTOGRAPHIC NEWS. 19 The instantaneous views of London from the top of an omnibus, by W. Cobb, are here, and have taken the silver medal for the best instantaneous pictures, not marine ; but these also are too well known to need description. “A Wreck on the Pier ” (438) is a very dramatic picture; it is low in colour, but is a wonderful rendering of a most difficult scene, and is the work of M. Auty, who sends besides some marine studies—“The Ferry,” “ Tynemouth Bar,” and Shields Harbour”—all of which are extremely artistic. The homely interiors by J. Terras strongly resemble in treatment the work of Adam Diston, and exhibit great artistic feeling. Of these we prefer 442, a cottage interior with woman spinning. “In an Artist’s Studio ” (449), by E. Dunmore, is quite a little picture, admirable in every way, and has carried off the silver medal for interiors. The small studies by G. Hadley are most artistic, and have deservedly won the medal awarded to the series, for both the cottage interiors and the very natural groups of fishermen are equally worthy of praise. He has also some instantaneous studies, in no way behind the others. Mr. H. Manfield, like Mr. Pringle, seems to have worked in every part of the world, and no matter whether in South Africa, Madiera, Italy, or Switzerland, the work is that of a most finished artist; and an old door-way, printed in platinum, is one of the finest pictures in the Exhibition. The interior of St. John’s Church, Malta, recently repro duced in the News, is here, as well as some other ex tremely good work by A. G. Tagliaferro. W. England has sent some fine carbon enlargements from his Alpine views, which have been hung a little too high for critical inspection; but they are extremely effective, notwithstanding. The platinum prints have all been hung together in a well-lit corridor, and undoubtedly gain by separation from the warm-toned silver pictures. Some of the most effec tive pictures in this department are the snow scenes of G. Renwick. Some cabinet vignettes in platinum are among the best examples of portraiture by this method of print ing we have yet seen. Some effective copies of pictures are sent by F. Hollier, who also sends examples of the application of photography to decorative work, and certainly those sent in are in no way behind the work of last year. The beautiful little landscapes by H. B. Berkeley are here, and to 567, “ The Thames at Pangbourne,” has been awarded the silver medal for small landscapes. It is an upright picture, and warmer in tone than the others sent by this gentleman, and we cannot help regarding it as one of the most perfect landscape studies ever produced. A very large series of reproductions are sent by R. Schuster ; they are called photo-etchings, bat no particulars have been sent with them. We are inclined to think they are produced by a modification of the collotypic process. At any rate they arc very beautiful, and have received a bronze medal. England Brothers send some interesting examples of platinum printing on linen. The School of Military Engineering exhibit some effective landscapes printed in platinum. On the table are some very successful lantern slides. The Swiss views of England Bros, are very clear and per fect, as are also those sent by F. York and Son ; and the examples of different tones to be obtained on gelatino. chloride plates, by Alex. Cowan, are most instructive. To the series of slides sent by P. II. Fincham has been awarded a bronze medal; they are very uniform in ex cellence, and are very bright on the screen. In conclusion, wo must say that the Exhibition deserves to be a success, for it reflects the greatest credit on the committee of management, who have done everything possible to make it popular as well as instructive. Every 1 ursday evening they have an excellent string band, and An exbibtionof lantern slides in one of the lower rooms, -ne -hibition closes on Thursday, January 12th. HOWTO PHOTOGRAPH MICROSCOPIC OBJECTS. BY I. H. JENNINGS. Lesson XII.— PREPARING CRY8TALLIZATIONS for PHoro- MICROGRAPHY. Most chemical crystals are mounted in balsam, as they are usually viewed by polarised light; but where this is inappli cable, or when the crystals are soluble in balsam, this medium must not be employed, and the crystals must be simply evaporated from an aqueous or alcoholic solation on a clean glass slide, and covered with a circle of thin glass. The majority of chemical salts are soluble in water, and when typical crystals are not required, the addition of a little gelatine to the water will usually produce larger, and in some cases more beautiful forms. However, as the genu ine typical forms will be generally required in a photo graph, it is best to use nothing but distilled water, or pure alcohol, in making up the solutions. To obtain typical crystals, the solutions should not be concentrated, but nor mal, and the evaporation of the salt should not be acceler ated by too much heat. As a general rule, the most per fectly formed crystals are obtained by very slow evaporation in a cool place. Many salts, if evaporated in a hot room, or over a lamp, give nothing but a confused mass of amor phous forms. It is often better, instead of applying heat to a drop of the solution on a glass slide, to make a hot solu tion in a test-tube, and evaporate a few drops slowly on the glass slip. Arborescent crystals, no matter how beautiful in themselves, are a great nuisance when the student wishes to prepare the typical forms for photography, and they may be avoided by allowing the solution to crystallize out slowly. Potassium bichromate, if crystallized rapidly, either over the lamp, or from a hot solution, usually gives arborescent forms; but when evaporated in the cold, the characteristic prismatic crystals are obtained. All salts crystallized from an alcoholic solution should, as a general rule, be evaporated in the cold. As an example of this, magnesium platino-cyanide, when evaporated from an alco holic solution rapidly, gives only an amorphous red mass. To obtain the prismatic crystals arranged in rosettes, the solution must be evaporated slowly in a cool room free from draughts. White arsenic, As, O 3 , may be obtained either from its aqueous solution, or by sublimation. The latter mode gives more brilliant and regular crystals, but is more troublesome. A small portion of arsenic should be put in a short test-tube about one inch long, and a glasr slide laid over the top. On applying heat, the crystals will form on the sides of the tube and on the slide. By a little careful manipulation with the spirit lamp, the bulk of the crystals may be driven from the sides of the tube and made to crystallize on the glass slip. They should be covered with a circle of thin glass—no balsam must be used, or they become too trans parent to photograph. The cuts (next page), photographed from slides of -OOI grain, and -002 grain of arsenic, show the general form of the crystals. Strychnine is very insoluble in water, so it should be crystallized from its dilute alcoholic solution. The form of the crystals is the octohedron, or square prism—usually the latter. As it dissolves in balsam it should be mounted dry. With a solution of picric acid strychnine yields hook-like crystals, which may easily be photographed with a low power. Brucia must be crystallized from alcohol. The crystals are oblique rhombic prisms. It dissolves in balsam rather rapidly, so should be either set up dry or in castor oil. Atropine, caffeine, and narcotine crystallize in needles. The former must be mounted dry. Morphia, and morphia chloride, sulphate, and acetate may be crystallized either from water or alcohol, and mounted in balsam. Q rinine sulphate gives a profusion of silky needles from a dilute alcoholic solution. Owing to their delicacy they are difficult to preserve, but may be mounted in dilute balsam and benzole,