He worked most of his life at Askov Folk High School where he developed the historic genetic method of teaching the sciences.
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.
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.
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.
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.
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 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 .
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.
The reason why la Cour abandoned this system in 1902 was that he failed to develop a gas engine based on hydrogen as a fuel, although years were spent on experiments.
His last electrochemical idea was the small scale production of artificial fertilizer using the process just invented by the Norwegians, Kristian Birkeland and Sam Eyde.
The classical windmills should be able to rotate in a gentle breeze, but the traditional miller was not able to utilize the huge amount of energy in a storm.
Although Daniel Bernoulli and Leonhard Euler had laid the foundation of modern fluid dynamics a hundred years earlier this had had no consequence for such complicated practical problems as that of the action of wind on wings; and in the cases where a computation was possible, theory did not match experience (Paradox of d'Alembert).
He concluded that in general all former theories and formulae concerning wings seemed to be incorrect; and to the extent they were correct, gave no information of any practical importance to the millwright.
The fact that la Cour's ideal mill looked very much like the traditional Dutch windmill resulted in some criticism of his work, and government support was reduced in 1902.
But by that time most of the experimental work had been completed and published, and he only considered these experiments a means to his goal which was the development of the rural areas in Denmark.
If people in a city or a village planned a power plant, la Cour was often invited to explain the advantages of this new energy source.
Comparing this total activity with the actual number of small rural electric power plants built in Denmark in the beginning of the century one[who?]