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ABSTRACT THE sixtieth issue of this welcome annual appears only a week or two later than in pre-war time, and the edition is increased from 25,000 to 30,000. This indicates a gradual

progress towards normal conditions. On the other hand, the volume is about seventy pages fewer than last year, and the price is increased. The obvious reticence of advertisers with regard to

quoting prices, which we remarked on a year ago, still impresses one, though perhaps less strongly. The editor contributes a lengthy article on general photographic procedure which cannot

fail to be of assistance to beginners. The usual “Epitome of Progress” is an excellent summary, extending to nearly 100 pages, of the notable events, business items, legal matters, novelties

in apparatus and equipment (including raw materials used in photography), and new methods or modifications of them. After the extensive collection of formulae follows “A History in Brief of

Photographic and Photomechanical Processes,” giving the year and sometimes the month and day of the chief events, beginning with Thomas Wedgwood's experiments, published by Davy in

1802. Of the other new matter, we are particularly glad to see that the editor has given a table which he calls “Corresponding Focal Powers and Focal Lengths.” The focal powers are given in

diopters, and the corresponding focal lengths in centimetres and in inches. Many lens problems are so very much more simple when calculated in diopters instead of in focal lengths that we

hope this table will be extended in next year's issue, and that there will be added to it a few simple instructions as to its use. The British Journal Photographic Almanac and

Photographer's Daily Companion, _1921_. George E. Brown Edited by. Pp. 840. (London: Henry Greenwood and Co., Ltd., n.d.) Price 2_s_. net. Access through your institution Buy or

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publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE J., C. _The British Journal

Photographic Almanac and Photographer's Daily Companion, 1921_ . _Nature_ 106, 692 (1921). https://doi.org/10.1038/106692a0 Download citation * Published: 01 January 1921 * Issue Date:

27 January 1921 * DOI: https://doi.org/10.1038/106692a0 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable

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