http://groups.yahoo.com/group/SurveyHistory/ Surveying History Thu, 08 Nov 2007 15:47:31 GMT ntxcousin http://groups.yahoo.com/group/SurveyHistory/message/241 http://groups.yahoo.com/group/SurveyHistory/message/241 Turns out the bottom eyepiece is an optical plummet as some suggested. If anyone figures out the the top item, I'd appreciate it. Thanks for the help so far. Wed, 07 Nov 2007 22:10:28 GMT Nicolàs de Hilster http://groups.yahoo.com/group/SurveyHistory/message/240 http://groups.yahoo.com/group/SurveyHistory/message/240 The top arrow points at what I think is a hole for electrical lighting. It will either illuminate the scales or the cross hairs or both. The eyepiece... I Wed, 07 Nov 2007 21:07:28 GMT ntxcousin http://groups.yahoo.com/group/SurveyHistory/message/239 http://groups.yahoo.com/group/SurveyHistory/message/239 I posted a picture of the Theodolite in the Photos section with two red arrows showing the parts I'm interested in learning about. The bottom arrow is the Wed, 07 Nov 2007 20:32:28 GMT Nicolàs de Hilster http://groups.yahoo.com/group/SurveyHistory/message/238 http://groups.yahoo.com/group/SurveyHistory/message/238 ... It looks to me that it is the optical plummet. When yoy mount it on a tripod you will see the ground through it. It serves the same purpose as a normal Wed, 07 Nov 2007 19:59:19 GMT Dan http://groups.yahoo.com/group/SurveyHistory/message/237 http://groups.yahoo.com/group/SurveyHistory/message/237 I've got a picture at: http://www.iowasurveyor.com/junk/topcon-arrow.JPG I drew an arrow to what I think you may be asking about. If it's not, then sorry. I Wed, 07 Nov 2007 19:44:58 GMT Nicolàs de Hilster http://groups.yahoo.com/group/SurveyHistory/message/236 http://groups.yahoo.com/group/SurveyHistory/message/236 ... Could you send me a picture of it or post one here? Nicolàs Wed, 07 Nov 2007 19:01:19 GMT James Kluttz http://groups.yahoo.com/group/SurveyHistory/message/235 http://groups.yahoo.com/group/SurveyHistory/message/235 ... .................................. Mike, Hold the eyepiece up to a strong light and if it is dark, it is probably meant to be attached to the telescope Wed, 07 Nov 2007 18:20:07 GMT ntxcousin http://groups.yahoo.com/group/SurveyHistory/message/234 http://groups.yahoo.com/group/SurveyHistory/message/234 I have a Topcon AG-20B Theodolite that I am looking to find a user/instruction manual for. It may not be an old unit historically but by modern digital terms Wed, 24 Oct 2007 15:01:46 GMT Root, Ray http://groups.yahoo.com/group/SurveyHistory/message/233 http://groups.yahoo.com/group/SurveyHistory/message/233 Dear Nicolas, I invite you to contact my wife, Mary Root, who just wrote a short article about spirit levels and has additional research. She is the editor of Wed, 24 Oct 2007 11:55:22 GMT Nicolàs de Hilster http://groups.yahoo.com/group/SurveyHistory/message/232 http://groups.yahoo.com/group/SurveyHistory/message/232 Dear group, A friend of mine came up with a question about a surveyor's instrument ... Can any of you help on this matter? The instrument is possibly of German Wed, 24 Oct 2007 11:23:42 GMT avalonf@... http://groups.yahoo.com/group/SurveyHistory/message/231 http://groups.yahoo.com/group/SurveyHistory/message/231 I just acquired a K&E "Whyteface" steel tape which is missing the pull tab on the end. If anyone has one they don't need or can tell me where to get one, it Tue, 04 Sep 2007 22:35:40 GMT tnesbitt.kychros@... http://groups.yahoo.com/group/SurveyHistory/message/230 http://groups.yahoo.com/group/SurveyHistory/message/230 Dan In the copy of Breed and Hosmer I have, revised by Alexander bone of MIT, printed in 1970, he is identified as George L. Hosmer, Late Professor of Geodesy. Tue, 04 Sep 2007 21:41:40 GMT Dan http://groups.yahoo.com/group/SurveyHistory/message/229 http://groups.yahoo.com/group/SurveyHistory/message/229 I am familar with George L. Hosmer who co-authored surveying text books with Charles Breed. Does anyone know of a George S. Hosmer that had anything to do with Fri, 20 Jul 2007 14:39:04 GMT W. Scott Smith http://groups.yahoo.com/group/SurveyHistory/message/228 http://groups.yahoo.com/group/SurveyHistory/message/228 Since there is no email contact for the SHS on its web site (http://www.surveyhistory.org/surveyor's_historical_society.htm), I thought this might be a good Thu, 31 May 2007 01:10:46 GMT konstantin202 http://groups.yahoo.com/group/SurveyHistory/message/227 http://groups.yahoo.com/group/SurveyHistory/message/227 Mark, Came across two books you might finuseful: Galileo Galilei, "operations of the geometric and military compass" isbn 0-87474-383-4 Smithsonian, 1978.