60 M. A. Colding on the History of the 



Having thus convinced myself that the new principle was con- 

 firmed, not only by all the experiments made before my time, 

 but also by the results obtained from my own experiments, I 

 had no hesitation in stating that there could be very little 

 doubt that perfect series of experiments would show my thesis 

 to be quite exact. 



I closed my discussion by showing that the discovery of a 

 perpetuum mobile would be possible if my principle was wrong. 



After the completion of the above-mentioned preliminary and 

 first memoir, of 1843, the Royal Society of Science furnished 

 me with money for the construction of a more perfect apparatus 

 than that which I had to employ in my first series of experi- 

 ments; and with that apparatus I subsequently carefully re- 

 peated the experiments, and found the results to be not only 

 more perfect than the first, but also quite in favour of my new 

 principle. 



At the same time I was very anxious to put the new principle 

 in a mathematical form that would enable me to include it in 

 the general formula of analytical mechanics by which all other 

 physical problems are treated, in a way very different to that 

 hitherto "incessantly" followed in the mechanical theory of 

 heat by all other physicists since Carnot; and I have always 

 been highly satisfied with the result to which these investiga- 

 tions led me, as it throws much light upon the well-known for- 

 mula, and likewise connects together the different forces of 

 nature in a simple, clear, and exact manner that will prove 

 itself to be successful. 



The results of these experiments and investigations were com- 

 municated to the Association of Natural Philosophers at a meet- 

 ing held in Copenhagen in 1847, and are printed in their memoirs; 

 they were afterwards laid before the Royal Society of Science, and 

 are also printed in their Transactions, partly in 1848 and partly 

 in 1850. 



In the following year (1851) I presented to the Royal Society 

 a memoir on the power of steam, which, based on the new prin- 

 ciple, treats the problems of steam-engines in a way very dif- 

 ferent to that formerly followed by Pambour and afterwards by 

 several other authors (according to the new principle) in the path 

 of Sadi Carnot and M. Clapeyron, but which, as I think, is not 

 less exact and instructive than the latter. 



The last memoir I have transmitted to our Royal Society of 

 Science on this subject contains "A Physical Investigation into 

 the general relationship between the Intellectual Powers and 

 the Forces of Nature/' 



In this memoir, contained in the Royal Society's Transactions 

 for 1856, I endeavoured to show that the new principle of the 



