Earhart Project Research Bulletin
July, 2002
Artifact 2-6-S-45

Secrets of the Knob

Preliminary Letter of Opinion

Analysis and photos courtesy Jeff Glickman, Photek Imaging.

Mr. R. Gillespie, Executive Director
The International Group for Historic Aircraft Recovery
2812 Fawkes Drive
Wilmington, Delaware 19808



July 12, 2002

Dear Mr. Gillespie,

This letter is my preliminary opinion regarding TIGHAR artifact 2-6-S-45 which has been in my possession and under examination since May 4, 2002. 2-6-S-45 is commonly known as the “knob” and appears to have multiple raised symbols on its surface. On May 8, 2002, the JPEG image file “knobref.jpg” was created using a Nikon 5000 digital camera, diffuse lighting, and the macro lens setting. The resulting knobref.jpg image defines 19 candidate symbol sites. During the course of the examination of 2-6-S-45, photomicrographs were taken of each of the symbol sites, and subsequently analyzed.

Analyses were performed in a controlled lighting “white box” consisting of a three-sided box of white foam core. A Celestron Microscope with a custom-built CCD imager was placed in the center of the white box. A 4x objective and a 10x eyepiece lens were used for the duration of the analysis. The CCD imager was connected to a frame grabber on an IBM-PC compatible computer. Captured images were analyzed using proprietary software, and individual symbol reports were prepared using Adobe Photoshop™. The illuminator used was a Mole-Richardson Co. Mini-Mole Type 2801 S/N 32375 with a Type 280108 Mole Focal-Spot collimator. The illuminator was mounted on a Matthews Studio Equipment (MSE) C-STD 2xR, FL 20.

Each symbol site was examined using “Optical Tomography.” This method uses an intense and highly collimated broad-spectrum illuminator which is rotated through 360 degrees in the XY plane around the artifact. After each rotation, the angle of the illuminator is increased by 5 degrees in the YZ plane. The resulting series of shadows reveal the detailed surface topography of an individual symbol on the artifact.

As previously reported, symbols 1 through 9 are PATENTED: ; symbols 10, 11 and 19 are NO., which account for 12 of the 19 symbols.

Seven of the 19 symbols remain. Given the context “PATENTED:” and “NO.” it is presumed the remaining 7 symbols are numeric, representing a United States utility patent number. These 7 symbols contain more contamination and damage than the initial 12, which resulted in ambiguity for some symbols. Information regarding each symbol can be found in the corresponding email for each individual symbol. This opinion letter shall summarize the findings of these 7 emails.

For each symbol numbered 12 through 18, the visible features of the symbol were compared with the features required for each number “0” through “9.” Each number “0” through “9” was either excluded or included on the basis of the visible features as a candidate symbol for the site. For some sites, this meant the symbol could be one of N possible numbers. The process of eliminating numbers at each site reduces the search space from 10 million possible patents. The following summarizes the numbers by site:

Symbol 12: 1

Symbol 13: 8

Symbol 14: 2, 9

Symbol 15: 1, 4

Symbol 16: 2, 3, 8

Symbol 17: 2, 9

Symbol 18: 5, 6

The number of possible combinations is computed by multiplying the number of possible values at each site together: 1 x 1 x 2 x 2 x 3 x 2 x 2 = 48. These 48 combinations are enumerated below in numerically ascending order. Each of these 48 combinations constitute a US patent number, each of which was retrieved using the online repository at the US Patent and Trademark office located at www.uspto.gov. The following information is summarized below for each patent: Patent Number, Patent Title, Award Date, Inventor, and Assignee, and are separated by commas. While all of these patents deserve careful scrutiny, two of them are of immediate interest.

1821225 Coat 9/1/1931 C.J. Lubin N/A
1821226 Automatic Discharging Toaster 9/1/1931 C.W. Mabey Mabey Electric Manufacturing Co.
1821295 Pipe Anchor and Clamp 9/1/1931 P.W. Dieter N/A
1821296 Truck Bolster with Spring Supported Side Bearings 9/1/1931 P.R. Drenning “T.H. Symington and Son, Inc.”
1821325 Rail Coupling 9/1/1931 A.A. Schaubut Lawrence H. Pugh
1821326 Process for Heating Decomposable Materials 9/1/1931 J.R. Schonberg Standard Oil Development Corporation
1821395 Vehicle 9/1/1931 C.E. Musslewhite N/A
1821396 Fuel Valve 9/1/1931 C.F. Nardin N/A
1821825 Safety Razor 9/1/1931 J.M. Zumwalt N/A
1821826 Portable Moving Racing Apparatus 9/1/1931 E.L. Ballew N/A


Fluid Handling Apparatus 9/1/1931 R.H. Owens International Stacey Corporation
1821896 Combination Sled and Wagon 9/1/1931 T.J. Phillips Wilbur F. Orr
1824225 Method of Packing Livestock for Conveyance in Transport Vehicles 9/22/1931 E.F. Mitchell N/A
1824226 Powder Buff 9/22/1931 C.A. Mureau N/A
1824295 Overload Vehicle Spring 9/22/1931 “A.M.J. Pohl , Et. Al.” N/A
1824296 Vehicle and Trailer Brake 9/22/1931 “G.I. Rawson, Et. Al.” N/A
1824325 Propelling System for Aircraft 9/22/1931 L. Breguet Societe Anonyme Des Ateliers D'Aviation
1824326 Production of Coke 9/22/1931 “W. Broadbrige, Et. Al.” Minerals Separation North American Corp.
1824395 Apparatus for the Measurement of Stiffness of Flexible Materials 9/22/1931 “T. Dantzig, Et. Al.” US Government
1824396 Bathtub Seat 9/22/1931 “J.W. Erhard, Et. Al.” N/A
1824825 Molded Laminated Gear Bank 9/29/1931 G.H. Mains Westinghouse Electric & Manufacturing Co.
1824826 Engine Starter 9/29/1931 Charles Marcus Eclipse Machine Company
1824895 Hood Latch 9/29/1931 D.P. Hynes Chicago Forging & Manufacturing Co.
1824896 Process of Producing Reduction Components of Carbon Monoxide 9/29/1931 A.O. Jaeger Selden Company
1891225 Motion Picture Film Treating Apparatus 12/20/1932 R.G. Fear N/A
1891226 Motor Control System 12/20/1932 G. Fox Freyn Engineering Co.
1891295 Cotton Tramper 12/20/1932 J.J. Wallace Gullet Gin Company
1891296 Vault Lock 12/20/1932 C.J. Wegner Perfection Burial Vault Company
1891325 Sprayer Device 12/20/1932 J. Fitch William Martin Vogel
1891326 Internal Combustion Motor 12/20/1932 D. Head N/A
1891395 Gun Sight 12/20/1932 G.O.C. Probert N/A
1891396 Filter Press 12/20/1932 P.W. Prutzman N/A
1891825 Gas Speed Toaster 12/20/1932 “P.J. Martell, Et. Al.” N/A
1891826 Spout and Closure 12/20/1932 E.L. McGinnis Consolidated Fruit Jar Company
1891895 Drive Screw 12/20/1932 C.E. Nagel Shake Proof Lock Washer Company
1891896 Suction Gathering Forming Machine 12/20/1932 K.E. Peiler Hartford-Empire Company
1894225 Electric Switch 1/10/1933 J.G.Peterson N/A
1894226 Folding Box 1/10/1933 L. Ross Beatrice R. Somach
1894295 Container Construction 1/17/1933 N. Scandore N/A
1894296 Die Head 1/17/1933 “H.T. Shearer, Et. Al.” Landis Machine Company
1894325 Fire Extinguisher 1/17/1933 “W. Richter, Et. Al.” N/A
1894326 Unloading Apparatus 1/17/1933 J. Satterquist Mill Engineering and Supply Company
1894395 Dowel Bar Device 1/17/1933 W.C. Burrell Robert R. Robertson
1894396 Cutter Package 1/17/1933 G.H. Gardner Menasha Products Company
1894825 Annealing Process 1/17/1933 F.C. Kelley General Electric Company
1894826 Safety Ticket 1/17/1933 F. Magidson Pittsburgh Tag Company
1894895 Detachable Suspension or Gripping Device 1/17/1933 “A.B. Steele, Et. Al.” A.B. Steele
1894896 “Wall Shield, Shelf and Ventilator” 1/17/1933 T.J. Sullivan N/A

The first of the two patents of immediate interest is:

1891395 Gun Sight 12/20/1932 G.O.C. Probert N/A

The diagram in this patent shows a knob similar to 2-6-S-45; however, the gun sight is for field artillery. Perhaps one could argue that during WWII field artillery might have been stationed on Nikumaroro, but there is currently no historical evidence to support this. Note that Probert was a British citizen seeking protection for his invention in the United States. This suggests that if 2-6-S-45 originated from a gun sight, that it might have been of British origin or manufacture, and possibly brought to Nikumaroro by an Australian, New Zealander, or Briton.

The second of two patents of immediate interest is:

1824826 Engine Starter 9/29/1931 Charles Marcus Eclipse Machine Company

This is interesting because William Bendix invented the automatic starter drive to eliminate hand cranking of automobile engines in 1911 and 1912. Bendix successfully licensed his design to Eclipse Manufacturing Company in 1913. Presumably over the next 15 to 20 years, Eclipse developed this technology, culminating in this patent which is a direct connect automatic electric starter specifically for aircraft engines. What is most interesting is that when I inquired with about how Earhart’s engine was started, I was told that the Lockheed 10E had an Eclipse direct electric starter, type E-160. While possibly coincidental, this is interesting enough to warrant research into the specific installation of the 10E’s E-160 to determine if there are any components which resemble the knob.

I recommend a review of all 48 patents, and detailed investigations into the above two patents with the intent of provably including or excluding them as matches to 2-6-S-45.

Ric, thank you for the opportunity to work with you again, and I look forward to our next project together. Please call me with any questions you may have.


Jeff Glickman
Board Certified Forensic Examiner
Fellow, American College of Forensic Examiners

Preliminary Letter of Opinion

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