How Many Triangles are insid...
How Many Triangles are inside me?Correct answers: 123
The first user who solved this task is Maja Inkret.
#brainteasers #math #riddles
First U.S. electric autoIn 1888, the first U.S. electric automobile, designed by Philip W. Pratt, was demonstrated in Boston, a tricycle powered by six Electrical Accumulator Company cells, weighing 90 pounds. Pratt held a number of patents as an inventor, the most significant being the first practical automatic fire sprinkler system (1872). His other inventions included furniture pads for chair leg tips (1878), a spring toy gun (1892), glazed target for vacuum-tipped toy arrows (1890), crutch (1901) and a bath mitten (1889). Some years earlier than Pratt's tricycle, in 1874, a three-wheeled electric vehicle had been built earlier by Sir David Salomons in Tunbridge Wells, England. It was a 1 h.p. device powered by Bunsen cells. By 1895, the first British manufacturer of electric cars was Acme & Immisch Electrical Works at Chalk Farm, London.«[Documentation on the 1888 tricycle is hard to find; only brief recent references found so far. Please contact Webmaster if you know of a primary source.] |