518 PRESENT FUNDAMENTAL CONCEPTIONS OF PnYSICS. 



one. In the theorem of the conservation of matter we have an analogue to 

 that of the conservation of energy ; the similarity of the two theorems 

 extends, however, only to the indestructibility and increatibility of mat- 

 ter and energy. In the following points some dissimilarities appear, to 

 wit : The doctrine of the conservation of matter may in all cases be es- 

 tablished with more ease and accuracy than that of the conservation of 

 energy, by direct qualitative measurement ; but as yet no transformation 

 of a simple substance into another has become known, while the mani- 

 fold transformations of energy have beeu learned. The possibility of 

 the transformation of the latter permits the assumption that there exists 

 but one single original energy, from which the individual energies 

 (gravitation, affinity, radiation, electricity, and magnetism) are the par- 

 ticular manifestations. It has been supposed, nevertheless, that possi- 

 bly one single, indivisible, elementary matter may exist, of which the 

 known elements might be variations or allotropes, in the same manner 

 as carbon, which appears as graphite and diamond; or as phosphorus, 

 which exists in the ordinary and the red forms; or as sulphur, in the 

 ordinary and the amorphous forms ; but as yet success has not been had 

 in the reduction of chemical elements to one single fundamental one of 

 which the hypothetical aether might even be a variation. 



In the same way as within the last quarter of the past century, the 

 emphasizing of the indestructibility and increatibility of matter caused a 

 complete revision and reform of the theories of chemistry, so in this cen- 

 tury, since the discovery of the indestructibility, transformability, and 

 increatibility of energy, a regeneration of the fundamental theories of 

 physics and of the exposition of natural science in general has taken 

 place; natural science thereby has regained its connection with philoso- 

 phy. On a secure basis, the fundamental theories of natural science may 

 now be deduced, and the bond of unity is now entwined around the for- 

 merly disjoined branches. Natural science gains thereby daily in sim- 

 plicity and depth, and the theory of the conservation of matter and 

 energy is the safely guiding compass on the sea of perplexing, individual 

 phenomena. And though the apothegm "Into the inmost heart of na- 

 ture enters no created mind " still remains true, the veil is at least lifted 

 which envelops that inner part of it. 



