[02 



NATURE 



[June 4, 1903 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



Coleridge's Theory of Life. 



The old subject of the nature of the vital force or vitality 

 having lately been under discussion, allow me to remind 

 some of your readers that Coleridge did not hesitate to 

 enforce his opinion that it came into the domain of the 

 scientific inquirer, and appertained to the other forces in 

 nature. I cannot express an opinion on his theories of the 

 nature of life, but his holding them in any tangible form 

 has had great weight with some persons, in consequence 

 of his being an orthodox Christian, belonging to what is 

 called the religious world, yet he considered that the nature 

 of life was open to investigation like any other natural 

 phenomenon. 



I may be allowed to quote a few passages for the inform- 

 ation of those who are not familiar with his essay on the 

 "Theory of Life." Coleridge's idea was that physical 

 life is a process or mode of operation, as we recognise under 

 such names as magnetism chemical affinity, for these, he 

 says, by their own properties affect all the results observed 

 in liiFe. " Life supposes a universal principle in nature with 

 a limiting power in every particular animal, constantly act- 

 ing to individualize and as it were figure the former. 

 Thus then life is not a thing — a subsistent hypostasis — but 

 an act and process." " To account for Life is one thing, to 

 explain Life another. To a reflecting mind indeed, the very 

 fact that the powers peculiar to life in living animals include 

 cohesion, elasticity, &c. (or, in the words of a late publica- 

 tion) ' that living matter exhibits these physical properties ' 

 would demonstrate that in the truth of things, they are 

 homogeneous and that both the classes are but degrees and 

 different dignities of one and the same tendency. Unless 

 therefore a thing can exhibit properties which do not 

 belong to it, the very admission that living matter exhibits 

 physical properties, includes the further admission that 

 those physical or dead properties are themselves vital in 

 essence, really distinct but in appearance only different ; 

 or in absolute contrast with each other." " If I were 

 asked for what purpose we should generalise the idea of 

 Life thus broadly, I should not hesitate to reply that were 

 ihere no other use there would be some advantage in merely 

 destroying an arbitrary assumption in natural philosophy 

 and in reminding the physiologists that they could not hear 

 the life of metals asserted with a more contemptuous sur- 

 prise than they themselves incur from the vulgar when they 

 speak of the life in mould or mucor. But this is not the 

 case. This wider view fills up the arbitrary chasm between 

 physics and physiology and justifies us in using the former 

 as means of insight into the latter." 



The author then proceeds to discuss his argument through 

 the lowest creatures in animal life until he reaches man. 



" The arborescent forms on a frosty morning to Re seen 

 on a window or pavement must have some relation to the 

 more perfect forms developed in the vegetable world." He 

 then alludes to the different classes of animals, and says, 

 " as the individuals run into each other so do the different 

 genera. They likewise pass into each other so indis- 

 tinguishably that the whole order forms a very network. 

 Man forms the apex of the living pyramid. He has the 

 whole world in counterpoint to him but he contains an 

 entire world within himself." 



It is clear, therefore, that Coleridge (and others may do 

 the same), whilst holding strictly to the belief in a spiritual 

 existence, yet regarded vitality from quite a different point 

 of view, resulting, indeed, from a combination of forces as 

 we see in other phenomena of nature. Samuel Wilks. 



Psychophysical Interaction. 

 Sir Oliver Lodge says (p. 53) that he would " interfere 

 with the course of nature," regarded as a mechanically 

 determinate problem, even by lifting a log. Why so? The 

 course of nature is exactly what happens, is it not? It is 

 the business of scientific men to find out the course of 



NO. 1753, '^OL. 68] 



nature, and the various connections which give it coherence 

 and consistency and determinancy. This has been largely 

 done, even in vital processes ; and in the obscurer regions 

 of psychics it seems probable that the course would be 

 determinate if we knew all the circumstances. In any case 

 we have nothing else but the course of nature to go by, in 

 the determination of ita^ws, and that psychic phenomena 

 are natural phenomena re, it seems to me, the only rational 

 view to take. Oliver Heaviside. 



May 21. 



May I contribute a pictorial illustration to the controversy 

 raised by Sir Oliver Lodge? 



P Q, part of a circular path described by a body of mass 

 m round a fixed centre C, under the influence of a con- 

 stant centripetal force of magnitude F. Whether this is 

 supplied by a string with a tension F or by an attraction 

 which will be constant if the path is circular does not seem 

 to matter in the least. 



Now let P T be the tangential distance which would be 

 traversed in a time t if the centripetal force were absent. 



When that force is introduced, P will come to Q instead 

 of to T, and the work done by the force consists of pulling 

 the mass from T to Q in the time t. The energy required 

 to do this is FxT Q, and the same amount is required and 

 absorbed in each successive interval of t. This result is 

 not affected by calling F a guiding force, which it is. If 

 instead of a body describing a circle we had dealt with a 

 body at rest in the position T, the energy required to bring 

 it to Q would be exactly the same. 



If Newton had had to express himself (modern fashion) 

 in terms of energy, can we imagine him dealing with the 

 problem except in some such way as my drawing indicates? 



Atheneeum. G. W. Hemming. 



ATMOSPHERIC ELECTRICITY. 



UNTIL within the last two or three years, the 

 advances made in our knowledge of atmospheric 

 electricity were mainly due to the investigation of the 

 electric field of the earth. An interesting summary of 

 the facts brought to light by such investigations will 

 be found in a paper by Exner in " Terrestrial Mag- 

 netism and Atmospheric Electricity " (vols, v., p. 167, 

 and vi., p. 1). 



Except at or near places where rain (or other form 

 of precipitate) is falling, there is in the free atmosphere 

 an electric field tending to drive positive electricity 

 downwards; the earth's surface is thus in fine weather 

 regions negatively charged. The strength of the 

 electric field and the magnitude of the_ charge per 

 square centimetre on level ground at a distance from 

 trees or buildings may be found by observing the 

 potential at a measured height. According to Exner, 

 the normal (fine weather) potential gradient in Euro- 

 pean latitudes varies from about 80 volts per metre 

 in summer to 400 or 500 volts per metre in winter. 



It has now been established by means of balloon 

 observations that the intensity of the electric field in 

 fine weather begins to diminish when a comparatively 

 small altitude is reached, and at a height of 5000 metres 

 has only a small fraction of the intensity at the earth's 

 surface. This shows that the lower layers of the atmo- 

 spliere possess a positive electrification very nearly 

 equivalent to the negative charge on the ground. 



