248 



NATURE 



[October 20, 192 1 



space-time is the death-knell of materialism, but 

 reflection will show that it must be so. If space 

 is not endless, but finite (and this is the essential 

 principle of the Riemannian geometry), and if 

 time is not in its existence independent of space, 

 but co-ordinate with the spatial dimensions in the 

 space-time system (and this is the essential prin- 

 ciple of the concept of the four-dimensional con- 

 tinuum), then the very foundation of the material- 

 istic concept is undermined. For the concept of 

 relative space-time systems the existence of mind 

 is essential. To use the language of philosophy, 

 mind is an a ■priori condition of the possibilitv of 

 space-time systems ; without it they not only lose 

 meaning, but also lack any basis of existence. The 

 co-ordinations presuppose the activity of an ob- 

 server and enter into the constitution of his mind. 

 If you distinguish, as, of course, you must and 

 do, the observer from his space-time system, it 

 is not a distinction of two separate existences 

 externally related ; they exist only in their rela- 

 tion, as when, for example, w'e distinguish an 

 activitv from its expression. 



This is not a metaphysical gloss on a scientific 

 principle, nor is it an attempt, as some may think, 

 to obstruct the clear path of scientific progress 

 with speculative cobwebs ; it is the plainest matter 

 of fact. Everyone who ignores it will simply 

 find himself left stranded, unable to play any part 

 in the conquest of the new realm opening before 

 science. 



In fact, it is not from philosophy, but from 

 science, that this rejection of materialism comes. 

 No one has expressed it with greater force and 

 with fuller conviction of its fundamental import- 

 ance than Prof. Weyl. In the introduction to the 

 book which I have quoted, the whole of which is 

 devoted to an exposition of the principle of rela- 

 tivity, he says : — 



Whatever matter might ultimately prove to be, one 

 thing we have always felt we knew for certain : that 



it is a substance underlying all change, and that 

 every bit of matter could be measured as a quantity. 

 Its substantial character found expression in a law 

 of conservation. We believed the quantity of matter 

 remained constant throughout all change. Till now 

 philosophy has usually regarded this as a priori know- 

 ledge, unrestricted alike in its generality and in its 

 necessity. To-day the certainty is changed to doubt. 

 After physics in the hands of Faraday and Maxwell 

 had set up another character, the field, above that of 

 matter, and after mathematics on the other side, bur- 

 rowing during the last century in a logical exploration 

 beneath the basis of Euclidean geometry, had 

 destroyed our confidence in its evidence, there has 

 burst in our days a revolutionary storm which has 

 swept away the ideas of space and time and matter, 

 which till now had been the firmest supports of 

 natural knowledge, — only, however, to make room 

 for a freer and deeper insight into things. 



Materialism is essentially a monistic and atom- 

 istic conception of reality. For it matter is 

 primordial, and mind is derived. Philosophers from 

 the beginning of philosophy have been conscious 

 of the intellectual diflficulty of such a concept, but 

 it has always seemed, even to philosophers, a 

 necessary presupposition of physical science. 

 Science, it was conceded, must at least proceed 

 as if it were so. The principle of relativity is the 

 rejection of it, a rejection based on the discovery, 

 not of theoretical difficulties, but of practical 

 matters of fact. The supposed fundamental 

 reality on which materialism as a world-view was 

 supported has proved a vain illusion, and 

 materialism is left in the air. The new scientific 

 conception of the universe is monadic. The con- 

 crete unit of scientific reality is not an indivisible 

 particle adversely occupying space and un- 

 changing throughout time, but a system of refer- 

 ence the active centre of which is an observer co- 

 ordinating his universe. The methodological 

 difference between the old and the new is that 

 mathematics is a material, and no longer a purely 

 formal, science. 



Damascene Steel and Modern Tool Steel. 



THREE years ago Col. N. T. Belaiew pre- 

 sented to the Iron and Steel Institute the 

 results of a very careful study of the general 

 properties and structure of Damascene steel, and 

 pointed out the great claims it had to the atten- 

 tion of all those interested in tool steel. He has 

 now contributed a second paper, entitled 

 "Damascene Steel," to the proceedings of the 

 institute, September, 1921, in which an endeavour 

 is made to substantiate this statement, especially 

 as regards high-speed steels. In his view a 

 marked analogy exists in the structure and also in 

 some of the properties of both types of steel, and 

 a comparative study, therefore, will probably 

 prove beneficial in explaining the properties of 

 these materials and improving the qualities of 

 existing rapid-cutting tools. 



Damascene steel belongs to the hypereutectoid 

 series of carbon steels with an average content 

 NO. 2712, VOL. 108] 



of about 1-5 per cent, of carbon. This carbon 

 exists as iron carbide, FcgC, the well-known 

 cementite; 1-5 per cent, of carbon represents 

 22-5 per cent, of cementite ; about one-half of 

 this is present with ferrite aS the eutectoid 

 pearlite ; the remainder forms excess or free 

 cementite. Of this the latter is distinctly the 

 coarser, and in order to globularise or spheroidise 

 the plates in which it exists in the casting, re- 

 peated careful hammering and heating are neces- 

 sary'. In this operation the plates are first broken 

 down into small, irregularly shaped crystals, and 

 are afterwards spheroidised, being of such a size 

 that surface tension is able to exercise a marked 

 influence on their ultimate form. The complete- 

 ness of this spheroidisation is shown in the photo- 

 micrograph of an Indian Damascene blade con- 

 tained in the author's paper, in which the large 

 spheroids have resulted from free cementite, while 



