Wednesday, 29 August 2018

An old intrument of Lord Kelvin

I'm on a family holiday, staying in a house which belongs to a relative of Lord Kelvin, and which contains a box with the following note on the top:

The note reads "Does anyone know what this is?  A. Hilger was a late 19th century / early 20th  century instrument maker.  Beware: Box is in two parts (deliberately, I think)". 

Opening it up reveals the following.

It's reasonably obvious how to assemble it:  A post screws onto the base, and an optical instrument clamps into the top of that.  At one end is an eyepiece.  There are spare eyepieces in the box.

Near the eyepiece end there is a mirror to reflect some light down into it.

 At the end opposite the eyepiece end, there is a prism which swings round to the opening, and a calibrated screw to adjust the position of it.

Anyone have any ideas what it is and what it was used for?

1 comment:

  1. First time here at your blog and wanted to say i enjoyed reading this