Tabular Data on Photographic Films

Abstract

THE Jahrbuch des Meteorologischen Observatoriums auf dem Donnersberge (B¶hmen) for 1929, edited by Dr. Pollak, is a very slender volume compared with its predecessors. The explanation is that, partly from motives of economy, the usual tables which make up most of the volume have not been printed. Instead they have been typed, and the typescript has been ‘filmed’ on Agfa non-inflammable films, the whole of the tabular matter being set out in a continuous ribbon made up of individual pictures 18 mm. wide and 24 mm. in height which accompanies the printed portion in a small tin box. This ribbon, which measures considerably less than 2 metres in length, can be rolled into a compact cylinder of cross section less than 2 cm. in diameter and in that form occupies less space than a small box of matches, the weight being extremely small. It is evident that had the whole year-book been treated in the same way the above rough description of its size and weight would still have applied to it, whereas the corresponding volumes for previous years are nearly 1 centimetre thick, and have pages measuring 31 cm. 23 cm. In the 1928 volume Dr. Pollak discussed the method of reproduction of his year-books by filming. He illustrates and describes there an apparatus manufactured by Askania-Werke A.G., Berlin-Friedenau, with the aid of which successive portions of the reel are strongly illuminated and can be brought under a powerful magnifier, but this arrangement appears very awkward for anyone using a table at one end of the film and requiring to make frequent reference to tables at the other end. It is not easy to see how this difficulty can be surmounted—the provision of fast and slow movements corresponding with the coarse and fine adjustments of a microscope would not be a complete solution.