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Brunton Serial Number / Feature Comparison Table
A comparison table of serial numbers and features observed online to be used as an aid to determining age.
Index of Manufacturers: [Ainsworth] [Alpha] [Automatics_Ltd] [Brunson] [Brunton] [Denver_Geodetic] [Dietzgen] [GeoSurvey] [Hilger&Watts] [Kalart] [K&E] [Leeway] [Lietz] [Lutz] [Negretti&Zambra] [Nishina] [Sokkia] [Tamaya]
[Acknowledgements]
I began this page as a way to help me assign approximate dates to various pocket transits as they came up for sale on ebay. Any assistance that you can give in filling in some of the blanks would be most helpful, both to me, as well as to other Brunton collectors. Some of the blank areas in the table are features that I did not observe at the time, or features that I could not observe due to the information available.
Dates: I describe the dates in one of three ways. A date followed by a plus sign (+) indicates a beginning date of a possibly open ended range. For example, a Brunton which has an engraved patent number will give us a date that the unit cannot be older than. Obviously, if a patent was assigned in 1914, and the patent date or patent number is engraved on the unit, it could not have been made in 1894. A second method is a date by itself. This occurs only when a date is firmly established by an engraved date or date code. A third method is a pair of years, which gives a possible range of dates. This occurs in the Brunton Company line, for example: We know the Brunton Company was established in 1972, and we know that they changed their serial numbering system in 1985. Therefore any units with an older serial number type must have been manufactured between 1972 and 1985.
Abbreviations:I have used some abbreviations in order to make the table more manageable.
- Body Codes: 2 letter material, optional 3 letter finish
- Al: Polished Aluminum
- Al/Blk: Aluminum, Black paint
- Al/Grn: Aluminum, Green paint
- Al/Brn: Aluminum, Brown paint
- Al/Gra: Aluminum, Gray paint
- Co/Wht: Composite, White
- Co/Grn: Composite, Green
- Level Codes
- 1L: 1 Long Level
- 2L: 2 Long Levels
- 1L1R: 1 Long Level, 1 Round Level
- 1L1R/Y: 1 Long Level, 1 Round Level, Yellow "High Visibility" fluid
- Graduations: I will be describing the graduations as "D" for Degrees, "Q" for Quadrants, and "M" for Mils. Unless otherwise noted, "Degree" scales are from 0-360 counter-clockwise, marked every 10 degrees with tick-marks at each degree. "Quadrant" scales are from 0-90 in each quadrant, marked every 10 degrees, with tick-marks at each degree. "Mil" scales are from 0-6400, marked every 200 mils, with tick-marks at each 20 mils.
- Q: Quadrants
- D: Degrees
- M: Mils
- Clinometer Codes:Clinometer scales are marked in Degrees, grade, and Mils. Later models may have more than one scale, so I've noted the number of scales, and the number of supporting arms. Degree clinometer graduations are every 10 degrees with tick-marks by degree. A vernier scale is usually located on the swinging arm which is graduated with tick-marks every 10 minutes. Grade scales are marked every 20%, with tick marks every 5%. Mil clinometer graduations are marked every 200 mils, and there does not appear to be a vernier on most models. The codes are in the format: 2 characters arm type, 2 characters scale type, 1 or 2 characters graduations. Note that on models with more than one clinometer scale, the position of the letter denotes which scale is on top as the scale is being read.
- 1A1SG: 1 arm, 1 scale, grade
- 1A1SD: 1 arm, 1 scale, degrees
- 1A1SF: 1 arm, 1 scale, fractions (grade)
- 1A2SDG: 1 arm, 2 scales, Degrees over Grade
- 1A2SGD: 1 arm, 2 scales, Grade over Degrees
- 2A2SDG: 2 arms, 2 scales, Degrees over Grade
- 2A2SGD: 2 arms, 2 scales, Grade over Degrees
- Sights: I describe the sight types as this is an important indicator especially in the Ainsworth line. The two sight types are "1 hole" or "2 hole". The "2 hole" sights are the 'figure eight' or 'dual intersecting' sight holes. The code is 5 characters, where the first two describe the number of sights, the next two describe the sight hole type, and the last character describes where the short sight (if present) folds.
- 1S1HN: 1 sight, 1 hole, None
- 2S1HO: 2 sights, 1 hole, Outside
- 2S1HI: 2 sights, 1 hole, inside: Common on K&E models
- 2S2HO: 2 sights, 2 hole, outside: Common on Ainsworths
- 2S2HI: 2 sights, 2 hole, inside: Late models by Ainsworth and nearly all "Brunton Company" models
I have also begun abbreviating "Induction" as "Ind".
Wm. Ainsworth
William Ainsworth was a watch and instrument maker in Denver CO. I'll leave most of the history of this company to this link, but will note that it may be possible to date early Bruntons with the name variations of the company, however, there is some discrepancy regarding the dates of the name changes. According to NAMH, in 1905 "Wm. Ainsworth" became "Wm. Ainsworth and Son". According the Robert A. Paselk Scientific Instrument Museum at Humbolt State University, the firm became "Wm. Ainsworth and Sons" in 1899, or shortly thereafter.
Index by Year: [ 1894 ] [ 1905] [ 1913 ] [ 1914 ] [ 1926 ] [ 1946 ] [ 1962 ]
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S/N
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Date
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Body
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Levels
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Clin.
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Sight Type
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Magnet/Needle
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Damped
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Grad
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Slots
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Engraving/Marks
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Note
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105
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1894+
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Al
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1L
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1A1SD
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1S1HN
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Steel, straight, no arrowheads
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No
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Hand engraved on lid:
D.W.Brunton's
Patent
Sept.18 1894
Wm.Ainsworth
MAKER
DENVER, COLO.
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#105 is currently held in the collection of Jerry Mohlman, Gwinn, MI. This unit has the engraved star indicating north on the mirror hinge side of the face.
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254
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1894+
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Al
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1L
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1A1SD
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1S1HN
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Steel, straight, no arrowheads
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None
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|
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Same as #105
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This unit has the engraved star indicating north on the mirror hinge side of the face.
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404
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1894+
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Al
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1L
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1A1SD
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1S1HN
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Steel, straight, arrowheads at each end, not as slender as other Bruntons of this age. Probably a repair/replacement needle.
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None
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Q
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None
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Same as #105
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#404 has the engraved star indicating north on the mirror hinge side of the face. Sold on eBay June 2004, $698.88 (yes, that is not a typo, six-hundred and ninety-eight)
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614
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1894-1905
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Al
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1L
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1A1SD
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1S1HN
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Straight steel, no arrowheads
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None
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|
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Same as #105 with additional engraving:
"H.S. Crocker Co
San Francisco
Dal.
Agents"
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#614 was offered for sale on eBay February 2004, Item 3273329151, but the auction was cancelled before it completed. First reversed face: #614 is the earliest unit (so far) with the reversed face and north on the long sight side typical of all Brunton Pocket Transits to follow.
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904
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1894-1905
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Al
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2L
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1A1SD
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1S1HN
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Straight steel, no arrowheads
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None
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Q
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Present
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Same as #105
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#904 is currently held in the collection of Jerry Mohlman. The mounting grooves may have been retrofitted on this unit, as some later units lack this feature.
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2270
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1905-1911
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Al
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1L
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1A1SD
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1S1HN
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Straight steel, no arrowheads
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No
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Q
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Hand engraved on lid as follows:
D.W. Brunton’s
Patent Sept. 18-1894
Wm. Ainsworth and Sons
SOLE MANUFACTURERS
Denver,Colo.USA
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#2270 Auctioned on eBay April 2005, opening at $225.
Face is unpainted Al, with black
lettering. Date is based on the
name change of the company.
Pictures: [1] [2] [3] [4] [5] [6] [7] [8] [9]
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3387
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1905-1911
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Al
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1L
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1A1SD
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1S1HN
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Straight steel, no arrowheads
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None
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Q
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Same as #2270
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#3387 is currently held in the collection of Dr. John Gilbert, Adelaide Australia. Picture1, Picture2
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3585
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1905-1911
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Al
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2L
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1A1SD
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1S1HN
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Straight steel needle, no arrowhead at either end. I cannot distinguish N from S in the picture.
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None
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Q
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Same as #2270
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Face is unpainted Al, with black lettering on the clinometer scale. An image of this unit was seen on the Gemmary website, in their section discussing the features of genuine Brunton Pocket Transits. I strongly suggest you read their entire F-Files section.
Date is based on company name change.
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3643
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1905-1911
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Al
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1L
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1A1SD
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1S1HN
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Vertical bar steel, no arrowheads.
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None
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Q
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none
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Same as #2270
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#3585 auctioned on eBay February 2005. Body and mirror in good condition, but front sight bent badly. Pictures: [1] [2] [3] [4] [5] [6] [7] [8]
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3713
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1905-1911
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Al
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1L
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1A1SD
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1S1HN
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Straight steel needle, no arrowhead at either end.
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None
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Q
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Same as #2270
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Offered for sale on eBay, April 2004, Item 3290028885, opening at $400, no bids. Relisted May 2004, item 3292251505, Relisted March 2005, Item 6164459605, opening bid of $200.
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4677
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1905-1911
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Al
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2L
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2S1HO
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Straight steel needle, no arrowheads
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None
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Q
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Diag.
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Same as #2270
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#4677 is currently held in the collection of Jerry Mohlman, Gwinn, MI.
This unit displays a mix of features that illustrates the difficulty in assigning accurate dates to the early model units. Either this unit was retrofitted with later innovations (the second level, milled slots in the diagonal faces, second short sight, etc) or this unit was manufactured with those improvements before the patent was issued.
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5315
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1905-1911
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Al
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1L
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1S1HN
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Steel
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None
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Q
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s/b diag
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Engraved "George P. Moore Denver Colorado"
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Auctioned on eBay December 2003, $222.00
#5315 is currently held in the collection of Jerry Mohlman, Gwinn, MI. NOTE: First machine engraved unit on record
Pictures: [1]
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6507
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1911-1912
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Al
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2L
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1A1SD
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2S1HO
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Steel
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None
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Q
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diag
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Pat. Sept 18, 1894 Other Patents Pending
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Auctioned on eBay February 05, $236.57 with tripod (older spring type) and leather carrying case. #6507 is currently held in the collection of W. Hudson, Gilroy, CA
Pictures: [1] [2] [3] [4] [5] [6] [7]
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68xx
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1913-1914
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Al
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2L
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2S1HO
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Steel
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None
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Q
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s/b present
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Pat. May 27.13
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#68xx is currently held in the collection of Dan Flanders
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71xx
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1914-1926
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Al
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2L
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1A1SD
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2S2HO
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Steel needle, arrowhead at north end only, arrowhead painted white.
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None
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Q
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s/b present
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Machine engraved on lid:
D.W.Brunton's
Pat.Sept.18 1894
Apr.14 1914
Wm.AINSWORTH & SONS.
SOLE MANUFACTURERS
PAT.OCT.22,12,
MAY 27,13
DENVER COLO.U.S.A.
OTHER PATS PNDG.
71XX (The last two digits of the serial number were unreadable in the image.)
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Face is unpainted Al with black lettering on the clinometer scale. An image of this unit can be seen on the Gemmary website.
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7209
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1914-1926
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Al
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2L
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1A1SD
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2S2HO
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Steel needle, arrowhead at north end only, arrowhead painted white.
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None
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Q
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Sides
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Same as #71xx
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Offered for sale several times on eBay, May and June 2004, unsold with high reserves ($300, $275)
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8392
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1914-1926
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Al
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2L
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1A1SD
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2S2HO
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Steel needle, arrowhead at north end only, arrowhead painted white.
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None
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Q
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Sides
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Same as #71xx
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Sold on eBay September 2004, Item 2268582113. VGC, no case. $157.50
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8488
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1914-1926
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Al
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2L
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1A1SD
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2S2HO
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Steel needle, arrowhead at north end only, arrowhead painted white.
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None
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Q
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Sides
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Same as #71xx
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Currently held in the collection of J. Mohlman, Gwinn, MI.
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9892
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1914-1926
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Al
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2L
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1A1SD
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2S2HO
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Steel needle, arrowhead at both ends.
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None
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Q
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Sides
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Same as #71xx with additional engraving "C. A. Barabe, Iron River, Mich."
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Sold on eBay, May 2004, Item 3292278850, $125, currently held in the collection of J. Mohlman, Gwinn, MI.
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10258
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1914-1926
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Al
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2L
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1A1SD
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2S2HO
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Steel needle, arrowhead at both ends
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None
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Q
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Sides
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Same as 71xx with the additional post-manufacturing engraving "THE MIDWEST REFINING COMPANY" above the normal engraving, and "DENVER" to the left of the S/N, and "COLO" to the right of the S/N
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Sold on eBay, April 2004, #3287745127, $228.29
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10646
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1914-1926
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Al
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|
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Steel
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None
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|
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Auctioned on eBay, December 2003
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14711
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1914-1926
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Al
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2L
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1A1SD
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2S2HO
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Steel
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None
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Q
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Engraving identical to 71xx above, except for serial number
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Item resides in the Smithsonian National Museum of American History
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14539
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1914-1926
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Al
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2L
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1A1SD
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2S2HO
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Steel
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None
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D
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Offered for sale by the Gemmary
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17393
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1926-1946
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Al
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2L
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2A2SDG
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2S2HO
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Steel
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None
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Q
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Engraved as follows:
D.W. Brunton's
Pat.Sept 18, 1894
Wm.Ainsworth & Sons
Sole Manufacturers
Pat. Oct.22,12
May 27,13
Denver,Colo.U.S.A.
Pat. July 20 1926
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Auctioned on eBay, April 2004, Item 3288482294, $271.50 This is an unusual unit, representing a transition between the 1914 and 1926 models. It has the ca. 1914 style crossed long levels, and yet has the 1926 patent date listed. According to an email from Jerry Mohlman, advertisements by the Wm. Ainsworth company published as late as 1929 offer the older 'crossed long level' style as an option. It is unknown exactly when the 'round level' entered production, but it was certainly close to 1926.
Pictures #1 Pictures #2 This unit is currently held in the collection of William Hudson, Gilroy, CA
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18101
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1926-1946
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Al
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1L1R
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2A2SDG
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2S2HO
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Steel
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None
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Q
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Same as 17393 with the addition of a 'Natural Tangents' table surrounding the central engraving.
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Listed in an article by Peter H. von Bitter, published in Earth Sciences History, Vol. 14, No. 1, 1995
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18158
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1926-1946
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Al
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1L1R
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2A2SDG
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2S2HO
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Steel
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None
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Q
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Offered for sale by the Gemmary
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18598
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1926-1946
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Al
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1L1R
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2S2HO
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|
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all patent dates are shown on the cover up to 1926
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#18598 is currently held in the collection of Jerry Mohlman, Gwinn, MI.
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19297
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1926-1946
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Al
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1L1R
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2A2SDG
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2S2HO
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Steel
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N/A
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Auctioned on eBay May 2004, but unsold with zero bids, with a minimum bid of $100 on a reserve auction, Item 3292490206. Relisted as item 3293693036, unsold at $66 with an undisclosed reserve.
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19964
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1926-1946
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Al
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1L1R
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2A2SDG
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2S2HO
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Steel, white arrowhead on N end, black arrowhead on S
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None
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Q
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Sides
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Same as 18598
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Pictures: Lid with Engraving, Face, Unit on Tripod This unit sold with tripod on eBay for $178.50
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20106
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1926-1946
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Al
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1L1R
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2A2SDG
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2S2HO
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Steel, white arrowhead at N
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None
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Q
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Same as 18598
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Sold on eBay June 2004 Item: 6103662730 $114.50
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20776
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1926-1946
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Al
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1L1R
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2A2SDG
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2S2HO
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Steel, white arrowhead at N
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None
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Q
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Same as 18598
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Appears to have quite a bit of discoloration, including what appears to be a stain caused by the vernier arm. Auctioned on eBay May 2004, Item 3291420228, $89.08
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21762
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1926-1946
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Al
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|
|
|
|
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1894 and 1926 patent dates engraved on lid
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#21762 is currently held in the collection of Jerry Mohlman, Gwinn, MI.
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22945
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1926-1946 (ca. 1933)
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Al
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1L1R
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2A2SDG
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2S2HO
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Steel, white arrowhead at N, black arrowhead at S
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None
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Q
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Side
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#22945 auctioned on ebay Jun 2004, Item 6104655201
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23812
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