January 23, 1902] 



NA TURE 



267 



some thoughts which appear to me new. For example, 

 the question is asked, How comes it that all things 

 which we know on this earth possess at once elastic 

 energy as well as weight ? The answer is, that it is con- 

 ceivable that by a process of elimination all things which 

 have no weight have left our universe ; for the slightest 

 impulse would send them on a road into space, never to 

 return. A similar suggestion is put forward to account 

 for the coexistence and the proportionality of mass and 

 weight, and matter is defined in terms of energy as a 

 portion of space in which a number of kinds of energy 

 coexist. In reply to the question. Why do they coexist ? 

 it is answered that if they did not coexist we should be 

 without knowledge of that portion of space ; they may be 

 there singly, but if so they elude our senses or methods 

 of detection. 



Ostwald claims for this method of regarding Nature 

 that it is free from hypothesis ; that each conception 

 necessary for it has a demonstrable and measurable 

 capacity and intensity ; and that nothing is stated which 

 cannot be tested by experiment and measurement. 



It is impossible, in the limits of a review like this, to 

 follow the author in his contest with the "mechanical 

 explanation" of natural phenomena. An idea may be 

 gained of his method by the quotation, 



" Had our researches dealt originally with heat instead 

 of with mechanics, we might be reading books with 

 such titles as ' Motion Regarded as a Mode of Heat' ; 

 and there is as much justification for this title as for 

 the ordinary version.' 



Indeed, the phenomena of radiation begin to be 

 regarded as rapid alternations of conversion of electric 

 and magnetic energies into each other, and in this 

 the pictorial or mechanical idea is almost, though not 

 completely, abandoned and replaced by an energetic 

 interpretation. " Explanations," in the sense of pictorial 

 analogies, are bound in the long run to be fallacious, 

 and only those elements actually present in the 

 phenomena should appear in its representation. As 

 an illustration, it may be said that, in spite of our 

 knowing much about the relations of bodies towards one 

 another from an electrical standpoint, we are nevertheless 

 ignorant of the " nature of electricity." To this it is 

 answered that when we are acquainted with all such 

 relations we shall know as much of the "nature of 

 electricity" as is possible. 



Among the laws of energy are to be found the' follow- 

 ing : — Every equalisation of energy requires time for its 

 accomplishment ; no equalisation (Ausgleich) can ever 

 be complete. Only such energies can maintain them- 

 selves as distinct phenomena in space which, when 

 coupled with others, maintain a compound equilibrium 

 in which an increase of intensity of the one form is com- 

 pensated by an equivalent increase of intensity of the 

 other. In order that anything may take place, uncom- 

 pensated differences of intensity must be present ; the 

 uncompensated excess will act as if it alone were present ; 

 the weight hung from the spring will fall, unless it is 

 completely compensated by the tension of the spring ; 

 the spring will shorten, if the weight is not heavy enough 

 to keep it in equilibrium. 



While the happening of a.w occurrence is the resultant 

 of differences of intensity, what we term "matter" is 

 NO. 1682, VOL. 65] 



closely connected with capacities. The reason of this is 

 that chemically equivalent quantities or, in other words, 

 chemical capacities are either equal to or bear some 

 simple relation to other capacities. 



In treating of causality, Ostwald accepts Schopenhauer's 

 view that the mind is conditioned by the necessity of 

 ascribing a cause to all occurrences, as it must regard 

 them as existing in time and space ; but as with time and 

 space, he regards this condition as inherited. From the 

 point of view of energy, one form of energy is to be 

 regarded as the cause of another kind, into which it is 

 transformed, and it is to be noted that in such a trans- 

 formation energy of higher intensity is always converted 

 into energy of lower intensity. I n the case of compensated 

 energies, as, for instance, with a coiled spring, the cause 

 may be regarded as the small amount of energy 

 necessary to release or discharge it, that is, the removal 

 of the compensation of energies at one place. Another 

 group may be referred to a state in which the velocity of 

 change is insignificantly small ; an accelerator may be 

 introduced, thus acting as a discharging agent. Changing 

 his point of view, Ostwald suggests that the law of 

 causality is nothing more than another aspect of the 

 process of forming a concept. For this implies placing 

 together things which display agreement in properties, 

 and this " synthesis " may result either in the invention 

 of a name or in the statement of a law of nature ; 

 the applicability of this concept in new cases depends 

 only on our skill in originally forming the concept. 

 Passing to the discussion of " necessities of thought " 

 and applying them to the laws of logic, the question is 

 not. Are such laws inherently necessary ? but. Are our 

 concepts in general, and among them the laws of logic, 

 fitted to represent the sum of our experiences ? 



The phenomena of life next come under review. 

 Ostwald regards as the special characteristic of living 

 organisms self-preservation, that is, the preservation of 

 a "stationary" form of existence; the organism must 

 preserve its normal state by maintaining uncompensated 

 differences of intensity by continuous expenditure of 

 energy, and it does this by making use by its own act 

 of previously stored supplies of energy. Reproduction 

 is regarded as a special case of self-preservation. The 

 stores of energy, thus utilised, are mainly chemical, and 

 it is incidentally remarked how much more easily 

 chemical energy can be stored than any other form. 

 The rate of change is regulated by three methods — 

 first, by control of temperature ; second, by introducing 

 reagents only where they are required ; and third, by the 

 use of " catalysers," that is, of substances which have the 

 power of accelerating or of retarding chemical change. 

 Inasmuch as time is not a factor in chemical energy, 

 the retarding or accelerating action of catalysers requires 

 no " explanation." It is perfectly natural to suppose that 

 the presence of foreign bodies may exert mfluence as 

 regards the rate of the conversion of chemical energy ; 

 on the other hand, if the atomic hypothesis be accepted, 

 it is by no means evident why the motion of the atoms 

 should suffer change by the introduction of a substance 

 which, as it remains unchanged during the conversion of 

 chemical energy, brings no " force " to bear capable of 

 accelerating or retarding the supposed atomic motion. 



In the chapter on the "Purpose and Means of Life" 



