09 Apr 2012

Lost Capitol Hill: Edward Kubel and His Heliostat

While researching a piece on manufacturing on the Hill (see this month’s Hill Rag for more) I came across a curious book: Historical and Commercial Sketches of Washington and Environs: Our Capital City, “The Paris of America”; Its Prominent Places and People etc etc. Most of the book is a series of short pieces extolling all manner of enterprises in the city. I found everything I hoped for – and a lot more. It turns out that there was far more manufacturing on the Hill than I’d ever dreamed.

Continue reading for the link to my book release party at the Hill Center.

One of the operations listed in the book is that of Edward Kubel, “Manufacturer of Astronomical and Geodetical Instruments.” Intrigued by what is really no longer even remotely happening on the Hill, I researched Mr. Kubel a bit further. Turns out that he – and his business – were internationally known, and even had some connection with one of the earliest measurements of the speed of light.

Edward Kübel was born in Bayreuth, Bavaria, in 1820. He emigrated to the United States in 1849, where he soon found work in the US Coast Survey’s instrument shop, and lost the ‘ü’ in his name. Kubel eventually opened his own shop at 326-8 1st Street NE.

One instrument that he made was a heliostat, which was a simple clock-work driven mirror that would move along with the apparent movement of the sun through the sky, and thus project a steady beam of light onto either an object to be illuminated or onto a screen such that the image could be further analyzed. In those days before electric light, such a steady form of illumination was otherwise unavailable.

Kubel had not invented this item, rather, he was building on the patent of a Professor Reuel Keith, who worked at the US Navy Observatory. However, it soon became apparent that Kubel’s models were truly the best available, and praise for it came from far and wide.

An early user was Dr. Joseph J. Woodward, of the Armed Forces Institute of Pathology. Woodward was interested in the heliostat as a means of illuminating objects he wished to photograph, and in several instances, he mentioned this instrument in articles he published.

In 1878, Albert A. Michelson, who was an instructor at the Naval Academy, requested the use of the heliostat. Michelson was not interested in the instruments ability to illuminate, but rather in the fact that it delivered a steady, collimated, beam of light. He needed this to measure the speed of light, using a method that had been previously described by the French physicist Jean Bernard Foucault: A beam of light is bounced off a mirror that is rotating rapidly. The reflected beam then strikes another mirror located a fair distance away. By the time the reflected beam returns to the rotating mirror, the mirror has turned a tiny bit, thus deflecting the returning beam again. By measuring the angle of deflection and the speed of rotation of the mirror, the speed of light may be calculated.

Michelson's description of the experiment. The heliostat is at the bottom right corner, the rotating mirror on the left side. Taken from Michelson's book "The Experimental Determination of the Velocity of Light" (Google books)

Today, of course, the beam of light would be delivered by a laser, but that invention was still far in the future when Michelson made his experiment. In spite of this, Michelson’s error was all of .04% (though he thought that his error was only .017%)

What Kubel’s reaction to this insight was, is not recorded. That his work continued to be important is shown in his entry in the “Historical and Commercial Sketches” mentioned at the beginning of this article. It begins: “The 19th century could very properly be called the age of practical mechanism, not from its first discovetry (sic), but from scientific methods devised for converting it in its best form to practical human needs. In this connection it is eminently propert to make mention of Mr. Edward Kubel, manufacturer of astronomical and geodetical instruments.”

Kubel’s shop continued to produce quality equipment even after his death in 1896, as his son Ernest took over its operation. Kubel died shortly after the birth of his grand-daughter Florence, who made history in her own way many years later.


I am indebted to Silvio A. Bedini, who did much of the research on which this post is based, publishing it in 2002 in the Professional Surveyor Magazine.

The book publishing party for my book on the scandals of Capitol Hill “Wicked Capitol Hill” will take place this Friday, April 13, at the Hill Center. Please RSVP at this link.