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Number by catalogue: Yvert: 5470
Perforation type: 13 ¼x13 ½
Subject:
4.3 lei. The horisontal will wheel*
Additional:
*The horizontal wheel mill has been considered the "queen of the artisanal hydro technical installations" on the Romanian territory whose use was mentioned ever since the 13th - 14th centuries. On a vertical axle there are the ladle-shaped blades giving the system a supplementary force due to the appearance of a reactive jet. It was used in the areas where the water fallings had a low flow. Starting from the constructive principle of the "horizontal wheel mills", the American engineer Lester Allan Pelton invented the turbine which bears his name.
The original exemplars of the horizontal wheel mill may be seen at the Museum of Masterpieces of Science and Technology in Vienna and "Dimitrie Leonida" Technical Museum in Bucharest.
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This information was taken from official booklet of Romanian Post
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You also can look at official FDCs
Romania - World premieres, 1st part
Romania 2010.12.17
In issue: Stamp(s): 4
Printing: offset
Issued in: in sheets of 8 stamps & 1 label (3*3)