THE 



LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



JOURNAL OF SCIENCE. 



SUPPLEMENT to VOL. XXV. FOURTH SERIES. 



LXVII. Remarks on the Mechanical Equivalent of Heat. 

 By Dr. J. R. Mayer*. 



THE vast and magnificent structure of the experimental 

 sciences has been erected on only a few pillars. 



History teaches us that the searching spirit of man required 

 thousands of years for the discovery of the fundamental princi- 

 ples of the sciences, on which the superstructure was then raised 

 in a comparatively short time. 



But these very fundamental propositions are nevertheless so 

 clear and simple, that the discovery of them reminds us, in more 

 than one respect, of Columbus's egg. 



But if, now that we are at last in possession of the truth, we 

 speak of a method by the application of which the most essen- 

 tial fundamental laws might have been discovered without waste 

 of time, it is not that we would criticise in any light spirit the 

 efforts and achievements of our forerunners : it is merely with the 

 object of laying before the reader in an advantageous form one 

 of the additions to our knowledge which recent times have 

 brought forth. 



The most important — not to say the only — rule for the genuine 

 investigation of nature is, to remain firm in the conviction that 

 the problem before us is to learn to know phenomena, before 

 seeking for explanations or inquiring after higher causes. As 

 soon as a fact is once known in all its relations, it is therein 

 explained, and the problem of science is at an end. 



Notwithstanding that some may pronounce this a trite asser- 

 tion, and no matter how many arguments others may bring to 

 oppose it, it remains none the less certain that this primary rule 

 has been too often disregarded even up to the most modern 

 times; while all the speculative operations of even the most 

 highly gifted minds which, instead of taking firm hold of facts 



* Translated by G. C. Foster, B.A., from a pamphlet intended for 

 popular circulation, published in 1 851 under the title Bemerkungen iiber das 

 mechanische Aequivalent der W'drme. Von J. R. Mayer. Heilbronn und 

 Leipzig, 1851. 



* Phil Mag. S. 4. No. 171. Suppl. Vol. 25. 2 L 



