Tech Thursday: Leveling

This will be the last Tech Thursday post I author. It’s a bit of a bittersweet occasion for me, and I hope you all have enjoyed this as much as I have. So, without further ado, I’m going back one more time to my favorite source for Tech Thursday posts- the Rare Book Collection.

A few years ago, Woodson then-intern Susan Kirby made an online exhibit for the History of Science Rare Book collection, featuring some scanned images from a little volume entitled Traité du Nivellement by Jean Picard (1620-1682). Picard was a French astronomer credited with a number of advances in his field, the most famous being the first accurate measurement of the Earth’s size. He was also interested in surveying and hydraulics, and was the principle designer of the aqueducts and cisterns that supplied water to Versailles.

Traité was published posthumously by Phillippe de la Hire, a French polymath and contemporary of Picard. Broken up in sections, the book discusses the theory, instruments, and practices of Leveling, a kind of land surveying. La Hire also included a condensed version of another of Picard’s works, Measuring the Earth. The book includes many diagrams of surveying interments, many of which were original to Picard, including a level fixed with telescope lenses and reticules.





One thought on “Tech Thursday: Leveling

  1. Dear Sir: (jeffatthewoodson)
    I am a collector of antiques age 73 in Butler, TN. I have a G.E. Ammeter of the General Electric Co., Schenectady, N.Y. USA. TYPE DP2 RATING 15amps. No. 288107 and Tested Mar 20 1939.
    “To ME”, It is an older ammeter that the one you have posted in your article……. It does not have any data listing OR wording of the G.E. AMMETER in the glass view. It only the ‘reading meter display from (0 to 15). This could be the 1st one ever made by G.E. that I have. I can send photos of the Ammeter, if I can find a ‘way’ using the WEB. If you are interested in this ‘model’ please let me know.
    thanks, Tony F. Whalen (

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s