{"book":"adl0613","page":44,"text":"( 5 )\n\nNOTE:--Double bases give ranges in double yards, e.g.,\nworking with a double base or four cords, the drum\nreads 1,500. The range, therefore, is 1,500 yards\nmultiplied by 2 (or 1,500 x 2) or 3,000 yards.\n\nCaution.\n\n(a) No ranges beyond 1,000 yards should ever be\ntaken with a half base, that is, with one cord.\n\n(b) No ranges beyond 1,500 or 1,600 yards should\never be taken with an ordinary, or 25 yard, base,\nthat is with two cords.\n\n(c.) Ranges above 1,500 or 1,600 yards should be\ntaken with a double base, that is utilising the\nwhole four cords (50 yards).\n\nExceptional Cases.\n\n23.--A 25 or 50 yard base may not be obtainable,\nthen a 12 1/2 yard cord (or half base) must be used, but the\ndifficulty of getting good ranges is very much increased as\nthe very slightest movement of either No. 1 or No. 2 will\nbe magnified owing to the short cord employed.\n\n24.--With experts the instruments can be used with-\nout the telescopes, working fairly well and giving satisfactory\nresults.\n\nNOTE:--When the telescope is not used, the shutter\nis drawn to cover the openings of the telescope,\nand the observer then uses the peephole.\n\nSpeed of Observation.\n\n25. Trained observers ought to be able to take any range\nin 15 to 20 seconds, provided always that the instruments\nare out of their cases and the cords stretched.\n\n26.--After once picking up a moving object, five ranges\na minute ought to be easily recorded.\n\n27.--Finding the distance between two inaccessible\nobjects can be easily executed by the Mekometer.\n\nT. A. MARTIN,\nCALCUTTA.\n\nFINIS.","chars":1547,"image":"https://storage.googleapis.com/adl-page-images/adl0613/00044.jpg","first_page":1,"last_page":57,"title":"Mīzān al-masāfah مىزان المسافه","permalink":"https://afghanpress.org/book/adl0613/44","canvas":"https://afghanpress.org/iiif/adl0613/canvas/44","source":"https://afghanistandl.nyu.edu/books/adl0613/","source_pdf":"https://afghanistandl.nyu.edu/pdf/adl0613_download.pdf","rights":{"image":{"statement":"Public domain. NYU states: \"All works presented on this website are, unless otherwise indicated, in the public domain. The images available on this website may be freely reproduced, distributed and transmitted by anyone for any purpose, commercial or non-commercial.\"","uri":"http://rightsstatements.org/vocab/NoC-US/1.0/","holder":"New York University Libraries","source":"https://afghanistandl.nyu.edu/about.html","delivery":"Images are served from a copy mirrored by this project, not from NYU's servers, under the reproduction terms above.","endorsement":"This is an independent project. It is not affiliated with, endorsed by, or reviewed by New York University."},"text":{"statement":"Machine-generated transcription, dedicated to the public domain under CC0 1.0. No warranty of accuracy: see the provenance block on every page.","uri":"https://creativecommons.org/publicdomain/zero/1.0/","holder":"Steps Ventures"}},"provenance":{"text_produced_by":"gemini-3.1-pro-preview","thinking_level":"low","read_completed":"2026-08-09","per_page_confidence":null,"per_page_confidence_note":"Not recorded during the corpus run. No calibrated per-page score exists, and none is estimated here.","human_reviewed":false,"accuracy_context":"Roughly two thirds of characters agree with a modern printed edition of the same text. Much of the disagreement is editorial, not misreading. Treat the transcription as a finding aid and read the page image before quoting.","primary_source":"The page image. The text is an index into it."}}