Ludwig A. Colding - Scientific Work

Scientific Work

Colding found time for private scientific work in fluid mechanics, hydrology, oceanography and meteorology as well as electromagnetism and thermodynamics. He was largely responsible for founding the Danish Meteorological Institute in 1872. However, he is best remembered for what he himself termed the "principle of imperishability of the forces of nature." Colding was influenced by D'Alembert's principle of "lost forces", Ørsted, the Naturphilosophie to which Ørsted subscribed and his own religious upbringing.

My first thought concerning the imperishability of the forces of nature I have ... borrowed from the view that the forces of nature must be related to the spiritual in nature, to the eternal reason as well as to the human soul. Thus it was the religious philosophy of life that led me to the concept of the imperishability of forces. By this line of reasoning I became convinced that just as it is true that the human soul is immortal, so it must also surely be a general law of nature that the forces of nature are imperishable.

Colding first fulfilled his ambition to work alongside Ørsted, who was conducting experiments on the compressibility of water, in 1839. He summarised this work with a review of other data on compression and friction of various materials in his first published scientific paper. In this work, he went on to state that "the quantities of heat evolved are, in every case, proportional to the lost moving forces" though he did not calculate a mechanical equivalent of heat as Joule was to do in the same year.

With Ørsted's support, a further series of quantitative experiments was sponsored by the Royal Danish Academy of Sciences and Letters, culminating in a report in 1847. By 1850, Colding had obtained a value for the mechanical equivalent of heat, some 14% lower than the modern value (4.1860 J·cal−1) at a time when Joule had measured 4.159 J·cal−1. A subsequent calculation by Colding in 1852 yielded a value only 3% below modern values.