Edmund Draper Dating Table

Here you will find information about how to date your Edmund Draper antique survey instruments.
Since there were no records found for Edmond Draper we have put this information together based on observed instruments using design data and patent information.  We have also put together a list of instruments to help in dating these instruments.   Based on early designs Edmond Draper did not use serial numbers on his instruments and we have determined that Draper used no serial numbers from 1832 to approximately 1859. 

The dating equation is based on only two observed points so there may be some discrepancies. 
An observed transit with no serial number and made with Draper shifting head. Since Draper made his first instrument with shifting head after 1858 this suggests that numbering started after this date.  The highest observed serial number is 626 and this instrument must have been made before Draper’s death in 1882.

Also the assumptions that:
The numbering started at zero
The number of instruments produced per year is constant So we are assuming Instrument serial number # 1 was made in 1860 and # 600 in 1880 when Draper produced an average of 30 instruments a year.  
The average number of instruments produced is confirmed by the Decennial Census of Industry in 1860 & 1870 reports.
The calculated value of 30 instruments per year is reasonable since Young & Heller & Brightly at the same time, with a larger shops, were producing 100 instruments per year.

The formula we are using:   Year = 1860 + serial number/30

Sample:
Serial Number 423 made in 1874

How to calculate:  423/30=14.1 + 1860 = 1874

In view of the limited data the equation must be used with caution and errors of plus or minus 5 years and possibly larger are to be expected.

Observed Instruments

****If you have any Edmond Draper instruments please let us know some details about the instrument so we can refine our details.****

Serial Number

Instrument  Type

Remarks

Est. Date

N/A

Compass

 

1832-60

N/A

Compass

 

1832-60

N/A

Level

 

1832-60

N/A

Compass

 

1832-60

N/A

Compass

 

1832-60

N/A

Transit

1832-60

N/A

Transit

 

1832-60

    Draper Introduced the Shifting Head in 1858  

N/A

Transit

Draper shifting head

1860

140

Transit

 

1865

169

Level

 

1866

220

Transit

 

1867

240

Transit

 

1868

347

Transit

 

1872

414

Transit

 

1874

472

Compass

 

1876

618

Compass

 

1881

626

Compass

 

1881

 



Serial number locations on some Edmund Draper instruments.


Click on image to enlarge.
 
Possible Location On A Transit
Edmund Draper Serial Number Location
Possible Location On A Transit
Edmund Draper Serial Number Location