Paracetamol under crossed polars by Mike Samworth
How to clear a headache
Paracetamol may be better at improving your mental well-being than you give it credit for. Crush a tablet and dissolve in methanol. This is best done with small amounts as methanol could well give you a headache itself, and the powder is not very soluble in it. Place a drop onto a scrupulously clean slide and let dry. Observe under crossed polars. Not all slides will look very good, and so make several at once. When you have a good one, cement a coverslip on as this will improve it.
Paracetamol under crossed polars by Mike Samworth
Editor's note: methanol is highly toxic and should only be used by experienced users in an appropriate manner and not by minors. More readily available and less toxic alcohols such as surgical spirit or isopropanol could also be tried.
Read Technicolour nature part 1 and part 2 which are two introductory articles on using polarised light in microscopy.
Norbert's Ruling machine (Times 6th March 1885)
The other night I was reading about different compressoria and similar devices in 'The Microscope' by Jabez Hogg. As I turned the pages in this magnificent book, a small newspaper cutting from The Times fell out. The article was about Norbert's ruling machines and was dated 6/3/85. Below is an extract.
"We are informed by Mr. J. Mayall, junior, of 223, Regent St. that the ruling machine by which the late Herr. F. A. Norbert, of Barth, Prussia, produced his extraordinarily fine rulings on glass, and about the construction of which there has been much mystery ever since the rulings were first brought to public notice at the Exhibition of 1851, has recently been acquired by Mr Frank Crisp, secretary of the Royal Microscopical Society, and that it will be exhibited at the meeting of the society at King's College, Strand, on Wednesday, the 11th inst. at 8 pm.
The fine rulings produced by Herr Norbert are held in high esteem by microscopical physicists, not so much on account of their fineness or accuracy of division, but on account of the depth and strength of the lines, on which their visibility and utility so largely depend. The mystery regarding the means employed to produce the rulings has now been largely cleared up, as the diamond points and the memorandum book relating to them has now been acquired along with the machine.
The latest achievement was the production of a series of 20 bands of lines, on a plate of glass ranging from 1/11,240th to 1/225,336th of an inch".
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