Poul la Cour (13 April 1846 – 24 April 1908) was a Danish scientist, inventor and educationalist. Today la Cour is especially recognized for his early work on wind power, both experimental work on aerodynamics and practical implementation of wind power plants. He worked most of his life at Askov Folk High School where he developed the historic genetic method of teaching the sciences. Early in his life he was a telegraphic inventor working with multiplex telegraphy.
Biography Poul la Cour was born on 13 April 1846 on a farm near Ebeltoft in Denmark. His father was a modern farmer introducing new technology at his farm as the first among neighbours. However la Cour had his gifts in mathematics from his mother. At Latin school in Randers he performed very poorly in languages and had to give up an early wish to become a priest. His brother Jørgen la Cour (1838–98), who knew the possible directions of study in Copenhagen, soon directed his brother into the new field of meteorology.
Telegraphic inventor After having finished his studies in physics and meteorology in Copenhagen in 1869 Poul la Cour travelled in Europe to study practical meteorology. He received his most important inspiration from the Dutch meteorologist de Buijs Ballot, with whom he spent a month. He became convinced that Denmark should set up a planned meteorological institute according to the principles of de Buijs Ballot. During the next five years his life was closely interwoven with the early history of the Danish Meteorological Institute, which was founded in 1872 with him as a Deputy Director. Telegraphy, the most important technological prerequisite for modern meteorology, soon became his main interest. In June 1874, the year in which Edison invented his quadruplex telegraphy, la Cour invented a telegraphic device based on tuning forks. The idea was to permit a number of telegraphers to send messages on a single wire, each using his own frequency. By using the resonance phenomenon of tuning forks it was possible to split out the messages at the receiving end of the wire. He patented his invention in London on 2 September 1874, but in the United States Alexander Graham Bell, Elisha Gray and others had been working along similar lines, which resulted in protests against his American patent applications. Having too little money to pay lawyers, he gave up his claim in America, and this invention was credited to Elisha Gray. La Cour however maintained that Gray had been working on the invention of the telephone, and only had changed his invention at the instant la Cour's American application was published. La Cour later wrote in an autobiographical article that he felt some malicious pleasure when Graham Bell was awarded the telephone patent by applying only a few hours before Gray. In 1876 la Cour could demonstrate 12-fold telegraphy with his system, and the Great Nordic Telegraph company was interested in it for some time. However, only the Danish Railroad Company seems to have used his invention in Denmark. After the disappointment on the American market, he produced a new invention, the phonic wheel: a synchronous motor driven by a tuning fork, which used an electromagnet to rotate the cogwheel of the motor by one tooth for each vibration. With two synchronous phonic wheels at a distance, a multitude of telegraphic devices was possible. This time there were no problems with the patent. The invention was produced in August 1875, patented in 1877, and the details were published in the book The Phonic Wheel in 1878 in a Danish and a French edition. At that time the invention was adopted by the American company The Delany Synchronous multiple Telegraph, and a new fight of priority arose. In 1886 the Franklin Institute awarded la Cour the John Scott Legacy Medal for the phonic wheel and at the same time presented Delany with the Elliott Cresson Medal for the synchronism, a decision la Cour protested against. The phonic wheel was used (in the form of Delany's multiplex telegraphy) on some telegraph lines on the East Coast of the US, and in the London Post Office. It was used as a chronometer, which was accurate to 0.00004 seconds in short time measurements. The most modern application was in the mechanical "television" of Paul Gottlieb Nipkow (1884).
The experimental mill at Askov 1891 During the 1880s there had been some criticism of the Grundtvigian historical approach in the Folk High Schools. In particular, the use of Nordic myths and realism gained a stronger position in Askov Højskole. La Cour's historical approach was not criticized much, but he also reread his Grundtvig and claimed that "in fact it is an indication of the power of history that I creates life (now)". In the 1890s la Cour and Askov Folk High School became more concerned with material reality, in teaching as well as in action. La Cour again became an inventor and experimental physicist, working for the benefit of the rural areas, form where most of the students came. Denmark is blessed with a lot of wind, and at a time where electricity was about to be introduced in Denmark, la Cour felt that the wind should contribute to the electrification of the country. In the Netherlands, the idea of electrification by means of windmills had been investigated with negative conclusions, because of their low efficiency, and the problems of storing energy . But these problems had appealed to the inventor and physicist la Cour. In 1891 he got the idea of storing wind as hydrogen (and oxygen) energy by passing the electricity through water and using electrolysis (Power-to-X). He was granted financial support by the Danish Government, and the first experimental mill at Askov was erected in the summer of 1891. La Cour's first task however was to "tame" the wind power, in order to make the mill produce a constant power in order to drive a generator. This was solved by the so-called Kratostate, a differential regulator, which later was simplified ("vippeforlaget") and widely used in electricity producing windmills in the Nordic countries and Germany.
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