Post by mourningdoves on Sept 13, 2017 22:22:27 GMT -5
Here is Antonie van Leeuwenhoek on a 1937 Dutch semi-postal. (The fine print below the image is the only way you can tell it's a semi; it says "toeslag 3½ ct".)
Leeuwenhoek had very limited formal education. Except for a brief time in Amsterdam, where he learned the fabric and textile trade, he spent his entire life in Delft. He did not actually invent the microscope; what he did was learn how to make lenses and build single-lens microscopes that were superior to any compound (multi-lens) microscopes around. While looking through his lenses, he saw things. He was the first person to view and describe single-celled organisms (apparently he had exceptional eyesight), and he wrote descriptions of red blood cells that were more accurate than any before. He also discovered bacteria (he called his microscopic findings "animalcules"), and he discovered spermatozoa - which, combined with his close observations of things like fleas and maggots, allowed him to formulate a new, accurate theory of reproductive cycles. He sent his descriptions to his fellow microscope fiend Robert Hooke, who got them published in the Royal Society's proceedings - and who learned Dutch just to be able to communicate with the monolingual Leeuwenhoek.
Post by mourningdoves on Sept 15, 2017 19:08:49 GMT -5
Heike Kamerlingh Onnes on a 1936 Dutch stamp. Like the Leeuwenhoek stamp just above here, it's a semi-postal; unlike the Leeuwenhoek stamp, there isn't any fine print, and I guess you're just supposed to know.
Kamerlingh Onnes (he had a double surname) was a physicist who specialized in how things behave at very low temperatures. For instance, he was the first person to liquefy helium, bringing it down below its boiling point, which is -269°C, or 4.2°C above absolute zero. He did that in 1908. A couple of years later, experimenting with lead and tin at similarly frigid temperatures led him to the principle of superconductivity. He also might have coined the word "enthalpy" (here is NASA's definition). For this and more, he received the 1913 Nobel Prize in Physics.
Post by mourningdoves on Sept 16, 2017 21:55:39 GMT -5
Here is Milutin Milanković on a 2004 stamp from what was then the State Union of Serbia and Montenegro.
Milanković was a mathematical prodigy, and after earning a Ph.D. in engineering and starting a career in Vienna, he obtained a job on the faculty of the University of Beograd. While he was on the faculty there, he supervised some engineering projects (such as road and bridge construction), represented Yugoslavia to the International (now World) Meteorological Organization, and developed a mathematical theory that set out to claim that there were patterns in climate change through the aeons: past episodes could be explained, and future ones predicted, through a complex series of data that included the distance of Earth from the Sun, continental drift, and changes in the orientation of Earth's axis. In a way, he took the mathematical foundations of weather that Vilhelm Bjerknes had established a few stamps ago and extrapolated their principles into the past and future. The stamp incorporates some of his theories in a concise, subtle way that science geeks of all stripes can enjoy.
And as if that wasn't enough, he wrote a series of pop-science books - the George Gamow of Serbia, you might say - and revised the Julian calendar to make it more accurate than the Gregorian, though it hasn't caught on so far.
Post by mourningdoves on Sept 18, 2017 21:55:47 GMT -5
Theodor Kjerulf, geologist, on a 1974 Norwegian stamp.
He performed one of the first exhaustive geological surveys of southern Norway. That work, and some earlier work in Iceland, were important contributions to our knowledge of the extent of the Ice Age and the long-term effects it had on northern geology. Information about him in English online is spotty - there is more in Norwegian - but this obituary. from the archives of The Geological Magazine (probably from late 1888) at Cambridge University, offers an appreciation of Professor Kjerulf's life and work.
Edited to add: He also published three books of poetry.
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