In autumn 1860, Hjorth was in Paris, and there he worked for his electrical inventions.
In 1866, Wilde published his machine, in which the current needed to magnetize the electro-magnets was produced by a permanent magnet. This is exactly the principle, underlying the dynamos built by Hjorth in 1854 and 1855. Hjorth’s good friend, Wm. Macredie, Melbourne, sent Hjorth a clipping from an English periodical mentioning Wilde’s machine, and called his attention to the identity.
It is to be regretted that Hjorth’s answer is not known, as his copy-book for 1866 has been lost.
Considering the data at hand when Hjorth’s biography was published in 1907, one might be inclined to believe that Hjorth had invented the dynamo principle and then dropped it at once, going back to steel magnets. It is, however, clearly evidenced, by the papers left by Hjorth, that this has not been the case, but that Hjorth has used the dynamo principle, in various, more or less pure, forms, in practically all his projects from 1851 to 1870.
[Fig. 7. Sketch of Hjorth’s Magneto-Electric Machine 1867.]
As previously mentioned, Hjorth had been disappointed in his attempts to produce energy through an electrical transmission of power, but this did not cause him to relinquish the idea of producing energy by electric means. He took this up again in a new form in his old age. In order to have this idea carried out in practice, Hjorth had a machine built, a description and drawing of which is to be found in a pamphlet published later on in French and Danish. From this it appears that the machine was not originally built according to the dynamo principle. Hjorth found no advantage in using the expensive electro-magnets, as it was his main object to prove that, by his special arrangement of armatures and magnets, he could reduce the power required to produce a certain amount of electrical energy. The machine, in its manner of construction, reminds one to some extent, of Hjorth’s project of 1851. Two or three rings, or wheels, of armature coils A (see [Fig. 7]) revolve between three or four circular rows of magnets M. This decreased consumption of power was to be attained by offsetting the armature wheels somewhat relatively to one another, for instance so that when one armature of the topmost wheel was opposite one magnet pole, an armature of the next armature wheel would be spaced one quarter of a pole distance from a pole, and an armature of the lowest wheel would be one half pole distance from a pole. As it is well known, this idea is entirely erroneous, it being contrary to the axiom of the constancy of energy.
The machine was built into a casing, and was sent to the Paris exhibition of 1867. Hjorth was always very careful not to give any information about his inventions to anybody. At the end of April, he went to Paris himself. The machine had suffered some injury on the journey, and had to be repaired in Paris, and therefore it made its appearance rather late. Still he succeeded in having it submitted to the judgment of the jury, and a test of electrolytic deposition was made, which proved entirely successful.
In Paris he met a certain business-man who, later on, requested to enter into partnership with Hjorth. This man was an adventurer, whose ambition was to become a Knight of Danebrog. It is only to be regretted that this person obtained so great a power over Hjorth, and understood how to deceive him. The previously mentioned pamphlet, edited by the partner, and named »Batterie magnéto-électrique de Søren Hjorth«, is a document of the poorest kind.
Through his partner, Hjorth was introduced to various electricians and men of science, among others the renowned Samuel B. Morse, who recommended Hjorth’s machine, but took exception to his idea concerning the production of energy.