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Images Dated 25th July 2003

Choose from 25 pictures in our Images Dated 25th July 2003 collection for your Wall Art or Photo Gift. All professionally made for Quick Shipping.

Anton van Leeuweenhoek, Dutch microcoscopist Featured 25 Jul 2003 Image

Anton van Leeuweenhoek, Dutch microcoscopist

Portrait of Antoni van Leeuwenhoek taken from his book Arcana Naturae detecta (1695). A Dutch microscopist, he was born in Delft, Netherlands, on October 14th 1632 & died on August 26th 1723. Leeuwenhoek built his own microscopes, grinding the lenses himself, according to a single-lens design that could magnify up to nearly 200 times. He was not the first microscopist, but his instruments enabled him to see further into the magnified world than any of his predecessors. His passion for observation & his discoveries revolutionised the science of biology. He was the first to observe & describe bacteria, protozoa, & sperm. Reference: MICROCOSMOS, page 186


Pearl necklace Featured 25 Jul 2003 Image

Pearl necklace

Pearl necklace. Pearls are accretions of nacre (calcium carbonate) secreted by certain oysters and mussels. The presence of a foreign body (such as a parasite or a grain of sand) within the shell triggers the secretion of nacre by the mollusc's mantle. Thin layers are deposited on the irritant particle and, over several years, a pearl is formed. Although commercially valuable pearls are obtained from freshwater mussels and oysters, precious pearls can come from ocean oysters. Cultured pearls are cultivated by inserting fragments of clam shell into the shells of farmed mussels and oysters