Several documents written by John Harrison have survived. A few have been reprinted, but only two are available here as a downloadable documents. Harrison wrote in the English language of the time, but he had great difficulty expressing himself intelligibly on paper - see Quill p. 210. He was also communicating ideas that were new and proprietary to him. The end result is that the documents written by John Harrison are sometimes difficult for modern readers to understand. Members of the Harrison research community, past and present, have made some progress in 'translating' the documents into modern English, but much remains to be done. Recent contributions by David Heskin and Anthony Zwygart are included below.
Most links below are not to downloadable materal - they are links to a horological literature database [BHM] that gives a more complete discription of the document referenced.
A very complete list of documents by John Harrison is given on pages 413-414 of:
The Quest for Longitude edited by William J. H. Andrewes
Martin Burgess states that there are three main sources of information about the technology Harrison developed - (Quest for Longitude - page 257):
An untitled manuscript signed 'John Harrison, Clockmaker at Barrow; Near Barton upon Humber; Lincolnshire. June 1730'
Transcriptions of the 1730 document were published in the Horological Journal by Baillie in August 1950 and by Aked in March, April 1976. Additional transcriptions are on the Yahoo HarrisonGroup site.
John Harrison, An Explanation of my Watch or Timekeeper for the Longitude ...' 7 April 1763
A manuscript held by the Worshipful Company of Clockmakers, Guildhall, London. No transcript copy is known.
A description concerning such mechanism as will afford a nice, or true measureation of time; together with some account of the longitude by the moon as also an account of the discovery of the scale of musik by John Harrison inventer of the time-keeper for the longitude at sea - London 1775
Peter Hastings has transcribed the last document and offered it to the horological science community. It is available for download here.
Peter states that "it is probably the first 'precision horology' text published in English - albeit in a somewhat opaque version of English." Obviously the document it is well out of original copyright but an acknowledgment of Peter Hasting's effort in transcribing it should be made by anyone who uses this document for any reason.
Anthony Zwygart had a copy made of the copy of "Concerning Such Mechanism .." in the US library of Congress and has transcribed what could be called a facsimile edition. He has tried to be as faithful to the original as possible, keeping the page formatting and layout exactly as in the copy of the Library of Congress original. He has used a period font with some of his own additions for special characters and ligatures. Anthony's fascimile copy of CSM is available for download here. Note: The first four pages are blank
A printed copy of the Library of Congress Document can be purchased from Amazon.com - search for "Concerning such mechanism"
A "Translation" of Harrison's CSM
With the firm objective of enabling access to what is widely regarded as a prohibitively complex and time-consuming manuscript, this publication is a modern (2011) "translation" of John Harrison's final (1775) pamphlet, commonly referred to as "Concerning Such Mechanism" or "CSM". Text relating to Harrison's principles of timekeeping and the determination of longitude at sea has been considered; Harrison's explanation of his theories of music is not included. This is not a technical interpretation; every effort has been made to preserve Harrison's original meanings without interference. In the interests of clarity and relative ease of reference, there has been some rearrangement of text and an occasional omission or abbreviation of repeated content. Paragraphs have been created from an original text almost bereft of such. Footnotes have been appropriately integrated within the text, for ease of reference. A copy of the 'translation' can be downloaded here. Literary elegance has been sacrificed to sensible translation. The original manuscript should be considered the work of reference.
David Heskin. Lancashire, England, June 2011