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Friday, 30 December 2011

Making your own microscope

Robert Hooke's 1665 microscope only
had a single lens

If you do a web search on <USB microscope> (leave out the "angle brackets"), and dig around, you will find instructions for making a simple 'microscope' from a webcam that plugs into a computer. Be warned that you need to be fairly handy with tools and a soldering iron to try this sort of thing. You might be better off looking around for one of the cheap models that is available, like the one I showed a while back.

Remember that good work can be done with just a single lens. Anton van Leeuwenhoek did amazing work in the 1600s with single lenses, and the tradition continues. Try a web search on <water drop microscope> and discover some neat designs for one-lens microscopes. Or read this, which appeared first in Charles Dickens' Household Words and then was reprinted in Scientific American, November 4, 1854, p. 64. Maybe you can see how to make such a "microscope" yourself.
 There is a man who sometimes stands in Leicester square, London, who sells microscopes at one penny each. They are made of a common pill-box; the bottom taken out, and a piece of window glass substituted; a small hole is bored in the lid, and therein is placed, a lens, the whole apparatus being painted black.
Upon looking through one of these microscopes, I was surprised to find hundreds of creatures, apparently the size of earthworms, swimming about in all directions yet on the object glass nothing could be seen but the small speck of flour and water, conveyed there on the end of a lucifer match, from a common inkstand, which was nearly full of this vivified paste.
I bought several of these microscopes, determined to find out how all this could be done for a penny. An eminent microscopist examined them, and found that the magnifying power was 20 diameter. The cost of a lens made of glass of such power would be from 3s. to 4s. how, then, could the whole apparatus be made for a penny?
A penknife revealed the mystery. The pill-box was cut in two, and then it appeared that the lens was made of Canada balsam, a transparent gum. The balsam had been very cleverly dropped into the eye-hole of the pill-box. It then assumed the proper size and transparency of a well-ground lens. Our ingenious lens maker informed me that he had been selling these microscopes for fifteen years, and that he and his family conjointly made them. One child cut the pillbox, another the cap, another put them together, his wife painted them black, and he made the lens.
It all sounds too easy, doesn't it? I suspect the man in Leicester Square and his family may have had a great deal of practice!

Coming up early next year: looking at a feather and comparing sand samples from different sources. I have been distracted because I needed to buy an Android tablet for my writing work, and I have started playing with it in a serious way.  The writerly side of me may look at the many meanings of table and tablet at some stage.

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