Letters to the Editor

Dear Madam, After having read Mr Negus's highly entertaining and informative paper on the juggling of edge‐punched cards, I cannot help wondering if, in changing to multiple‐entry subject card index, he still has not backed the right horse. Could not the ASM Metallurgical classification be put straight on to Peek‐a‐boo cards and used as a co‐ordinate index? This would be a less sophisticated form of ASTIA's automated retrieval system where document numbers are put on to magnetic tape instead of being punched on cards. Bill Barden, in conversation at the Aslib Aeronautics Group Conference in July [1961], expressed the view that a Peek‐a‐boo co‐ordinate index was extremely efficient for document collections of 100,000 or less, and that computer scanning was only a logical extension of a highly selective retrieval technique.