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?

Solar cell plagiarism

Here is an unfortunate case of plagiarism that has come to my attention via a nuclear physics colleague from Delhi on Facebook.

Here is the title and abstract of a paper published in Nature Energy (Konrad Domanski et al., Nature Energy 3, 61–67 (2018)) :

And here is the title and anstract of a paper published in Solar Energy Materials and Solar Cells (Zaeem Aslam et al., Solar Energy Materials and Solar Cells 185, 471–476 (2018)):

You might need to click on the pictures to be able to read the text, but the abstracts are both the same.  I understand the same is true for the full text, too, but I don't have access to the full papers.  I expect that the second paper (submitted 7th March 2018) will be retracted by the journal soon, leaving the first paper (published 1st Jan 2018) to stand. 

A-level grade boundaries

After the A–Level results are published, the exam boards release further details about the papers, including the grade boundaries.  Here is a document published yesterday from AQA, with such grade boundaries.  Scrolling down to the first physics paper gives fairly representative numbers.  In percentage terms, the scores needed for each grade are

A* 73%

A  60%

B  50%

C  40%

D  30%

E  20%

I don't think I knew these numbers before.  At Universities in the UK module pass marks are usually 40% (at least, I looked at a few at random: Southampton, Royal Holloway, Hull, and they all have 40%).  I dare say one has to demonstrate some real knowledge of the subject to hit even 20% of marks, so having a nominal pass outcome to show achievement at 20% seems reasonable enough.  Interesting!  70% seems to be a pretty standard University score for a first class degree (see p6 of the Southampton document, above), so actually, the A–Level and Unviersity schemes seem pretty will lined-up, except that a C grade at A–Level would be about the lowest grade to consider accepting without any other indicators to go on.

Flowers in the Office

Here is my hot tip for improving your working environment:  Buy (or grow) some flowers for yourself and put them in the office.  They always lift my mood, and cause people to ask me if I have an admirer (I don't).  It's especially useful if, like me, there is no plant life to be seen from your office window, especially since they have got rid of the moss on top of the bicycle sheds