It has been known for over 2000 years that glass bends light, but the first accurate lenses were not made until about the year 1300. Around 1600, it was discovered that optical instruments could be made by combining lenses.
Antony van Leeuwenhoek was a Dutch draper and scientist, and
one of the pioneers of microscopy in the late 17th century.
He made his own simple microscopes which had a single lens and
were hand-held. He made many drawings of what he saw and is
thought to have discovered bacteria, although he didn't know what
they were.
In the mid 17th century, Robert Hooke drew pictures of cork seen through his microscope. Like Leeuwenhoek, he did not know exactly what he had seen.
All the early microscopists saw quite distorted images due to the low quality of the glass and imperfect shape of their lenses. Lenses improved a lot through the 19th century, and the microscope as we know it was gradually developed.
In 1933, the first electron microscope was built.
Some dates:
1608 Credit for the invention of the microscope given to Zacharias Jansen
1611 Kepler suggests simple microscope
1614 Giovanni du Pont uses a telescope back to front to look at small things
1625 The word microscope first coined by Giovanni Faber
1665 Hooke published a book of his findings, called Micrographia
1826 James Smith produces first microscope with achromatic lenses
1833 Robert Brown identifies cell nucleus
Think of a penny. As you look at it at a magnification of x1 it is less than 2 cm wide .....
x100 as high as a man.
x1000 the width of four cars.
x10,000 the width of Westminster Bridge in London.
x 1 million as big as the London Underground.
x10 million as big as Wales.
x100 million as big as Europe.
x1000 million as big as the World.
I have been mesmerized by the beauty of the photographs in a new book recently. The book is called 'Freshwater Algae: their microscopic world explored' and is by Hilda Canter-Lund and John W G Lund, with the division of labours being photographs and text respectively.
The standard of images throughout the whole book is superb. I choose the word 'images' here quite consciously because in most cases the photographs are more than just well exposed records of the specimens, but rather display fully the true beauty of the algae. One technique that is used extensively to get effect is that of mounting the specimens in Indian ink to show the presence of mucilage which otherwise would have remained invisible. However, I think this technique has more to offer than that explanation would confer.
Over the last week or so I have slashed the ink around quite liberally (too much on occasion!) and I would fully recommend people to try it with their pond water samples, it is amazing how much algae it shows up. I find that mounting the sample as usual first is best, and then irrigate with ink by using blotting paper or tissue to draw the ink across. By using this method it is more likely that the right density of ink and therefore degree of opacity can be achieved. You may end up with messy slides but it certainly adds another dimension. Shortly I will put some images onto the site showing some of the effects.
For anyone wishing to obtain the very excellent book, the details are as follows;
Freshwater Algae: Their microscopic world explored, Hilda Canter-Lund and John W G Lund, Biopress Ltd,Bristol, 1995.
Editor's note: an illustrated article on the use of Indian Ink to show the mucilage surrounding desmids written by Bill Ells can be found in our on-line library under Pond-life.
Please do not hesitate to contact me if you have any comments or questions - Mike Samworth.
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