13+ Health Benefits of Apple Cider Vinegar. 1  Your Brain on Trust: Why Weâre Hardwired to Rely On Others. 2  19 Easy Ways You Can Torch 200 Calories In a Blink of an Eye. 3  This Mom Lost Over 150 Pounds by Cutting Out 4 Foods.
O. volvulus is transmitted by sandflies, and their role in the transmission of onchocerciasis was discovered by the Scottish parasitologist Breadablane Blacklock in Sierra Leone in the mid-1920s (19). There are accounts of the history of onchocerciasis by Grove (105) and Muller (192).
Chromium oxide was discovered in 1797 by Louis-Nicholas Vauquelin, who prepared the metal itself in the following year. Starting from crocoite the procedure was to powder the mineral and to precipitate the lead out through its reaction with hydrochloric acid (HCl in water).The residue was chromium oxide, CrO 3.Heating this oxide in an oven in the presence of charcoal as a reducing agent gave the metal itself. Vauquelin also analysed an emerald from Peru and discovered that its green colour is because of the presence of the new element, chromium.In fact, the name chromium is from the Greek word  chroma  meaning  colour , so named because of the many different coloured compounds displayed by chromium.A year or two after Vauquelin's discovery, a German chemist named Tassaert working in Paris found chromium in an ore now called chromite.hromium oxide was discovered in 1797 by Louis-Nicholas Vauquelin, who prepared the metal itself in the following year. Starting from crocoite the procedure was to powder the mineral and to precipitate the lead out through its reaction with hydrochloric acid (HCl in water). The residue was chromium oxide, CrO 3.