International Review of Educational Cinematography (Jan-Dec 1931)

96/ stresses the educational importance of the cinema. This is convincingly illustrated by a few figures, though not of very recent date. The use of the film for educational purposes in 44 thousand American churches and 6761 teaching institutes, the adoption of cinematography in nearly 6000 factories during the daily rest hour, for purposes of professional instruction, and the rationalisation of labour. By means of the cinema we can admire and learn from the Latin and oriental civilisations, which as Ducom points out, are almost a closed book to us to day. All this will lead sooner or later, but inevitably, to a greater and increasing mutual understanding among nations. And here lies one of the most exalted and noble missions of the film as a means of social and civil propaganda. The Cinematographic Projection, by Dr. H. Joachim (Knappe: Halle-Saale). A valuable treatise on the cinematographic projections and its attendant problems from the scientific point of view, both in the mechanic and electro-technical fields. The book opens with a brief indication of the importance of cinematography in the different fields of modern, social activity, and an examination of its future possibilities. It then reviews the different types of films now in existence, ways of using them, precautions to be observed, scenic repairs, etc. The author then proceeds to an examination of the projecting apparatus, which is minutely dissected and explained; the different types of projection, their use, and repairs are illustrated: various kinds of arc lamps, optical apparatus and compensations and their various systems. The author, stressing the necessity that the operator should have sound notions of electrotechnics, handles this subject in detail: he then passes on to the power, intensity and various kinds of electric current, and the laws by which it is governed, commutators, metres, transformers, dynamo, and all the auxiliary instruments of cinematography for projection and control in cinematographic halls. After having thus analysed the whole motor apparatus and its auxiliary apparatus, the author takes up the subject of the cabin as such, and the requirements it should fulfil. He then examines the question of cinema halls, their length, breadth, from the spectator's point of view, various types of screens, including those for day projections. The preservation of the apparatus and all its mechanical optical parts is next fully dealt with, also the prevention and elimination of errors in projection. The subject of the prevention of fire is also carefully and exhaustively handled; all the prophylactic measures and the use of the fire extinguishing apparatus being fully described. The last part of the volume is dedicated to the examination of different types of apparatus for schools, societies, etc. Several kinds of fixed apparatus and apparatus for ambulant cinemas are illustrated, the numerous models with their characteristics, power etc., are described and prominence is given to the prevention of conflagrations. This booklet is one of the best of its kind. Reifung von Bromo Silber gelatine mit Ammoniak Ammonium Karbonate, by O. Papesch, published by Wilhelm Knapp, Halle (Saale). An interesting dissertation on the influence of ammonia and the various salts of carbonate of ammonia on the preparing of gelatine of bromide of silver and their granular properties. The effects of the radical NH3 of carbonate and bicarbonate of ammonia, their sensitivity to light and the gelatinous preparation of bromide of silver are particularly examined, with special reference to the increase of granulosity of the bromide of silver during its preparation. Similar researches are made with ammoniacal solutions of nitrates and carbonate of silver and with a new compound salt discovered in the course of the present study: " compound salt of ammoniated carbonate of silver", it deals with the analytical proofs of the above-mentioned compound salts.