ii6 DESIGN IN NATURE 



even then, be cumulative proof that a Creator produced both kingdoms ; but when it is found that the two kingdoms 

 dovetail into each other and interact at innumerable points, and are, in the widest and fullest sense, complemental 

 as regards their matter and much of their force, then the proofs of a First Cause, a Sustainer, and Regulator are, it 

 appears to me, indefinitely strengthened. 



In considering magnetism, electricity, heat, and Hght we have to deal with the movements of the atoms 

 and molecules of matter, and of the ether which pervades space. Magnetism, electricity, heat, and light may be 

 said to merge into each other. They are all forms of motion, and are best treated together. A knowledge of 

 electricity is necessary to a comprehension of the others, and forms, in a sense, a prehminary inquiry. 



The precise nature of electricity is unfortunately not yet quite understood. Recent researches, however, make 

 it all but certain that the old idea of an electric fluid must be abandoned. Electricity, there can be little doubt, 

 does not flow as water and other hquids do. When an electric current passes along a wire, the transference is effected 

 by continuous molecular action propagated within and outside the wire : the action extending to the atmosphere. 

 There is a movement of the molecules of the wire, and of the molecules of the ether between and outside those of 

 the wire in the atmosphere ; the latter constituting the so-called magnetic field. ^ Both sets of movements take 

 the form of waves, and the molecules rotate as well as vibrate or pulsate : there are longitudinal wave and rotatory 

 transverse movements. The molecular action is primarily between neighbouring molecules ; the remote molecules 

 being afiected secondarily. The movements are not those of fluids streaming steadily in a particular direction 

 between the molecules, but vibratory wave movements of the molecules themselves in several directions ; the 

 advance or transference being due to what is practically a system of percussion, one molecule acting on another in 

 rapid succession not only in the wire but throughout space. The molecules have a vibratory progressive wave 

 movement in the aggregate. They have also transverse, rotatory, and, some think, spiral movements individually. 

 Each molecule has an environment to which it is confined, but the molecules as a whole have movements apparently 

 co-extensive with space. 



Professor Trowbridge of Harvard University, in his work, " What is Electricity ? " ^ points out that when fluids 

 or compressed air are made to flow through tubes there is no disturbance outside the tubes in the surrounding 

 medium ; a magnetic needle placed outside the tubes not being affected. It is otherwise when a current of electricity 

 is passed along a copper wire. In this case, when a magnetic needle is placed in the vicinity of the wire it is 

 disturbed or deflected, showing that the atmosphere outside the wire is involved. The conducting wire is surrounded 

 by an atmospheric magnetic field, which influences substances placed in it. While it is convenient in popular 

 parlance to speak of the flow of electricity, and of electrical currents, it is necessary to make a distinction between 

 the passage of fluids in the ordinary sense and that of electricity. In electrical transferences it is the ether prin- 

 cipally which is concerned. That ether exists is all but proved by the transference of energy in magnetic in- 

 duction. When an electric current is sent through one circuit it begets a current in a neighbouring circuit. The 

 energy which disappears in the exciting current reappears in the induction current, and must have existed in the 

 space separating the currents during the transference. A medium of some kind (beHeved to be ether) is necessary 

 to convey the energy through the intervening space in question. The phenomena of light also involves the existence 

 of a medium. 



" The old fluid theories impUed that when a body was electrified it had something upon it which was caUed 

 electricity. According to the modem views, we regard the ether around the body as charged with energy which is 

 the result^of the work we have done in charging the body. This energy in the ether is the energy of motion, 

 ihere is a^state of stram m the ether which we term a polarised condition. Around a positively charged body this 

 polarisation has a certam direction and a certain amount. With a negatively charged body this polarisation is 

 m an opposite direction. It is suggested that these polarisations may be Uke right-handed and left-handed 

 rotations or twists. When we electrify a conductor we store up energy around the conductor in the ether. The work 

 we do IS spent m changing the state of the medium. When a body is discharged, the medium returns to its original 

 state, and the energy is dissipated as heat in the electric spark or as heat in the conductor. The electric current 

 IS therefore the mamfestation of energy in the ether along the wire through which the current appears to flow. The 

 consideration of the rotation of the plane of polarisation of Kght by magnetic force led Maxwell to a theory of 

 magnetism which is called ' the hypothesis of molecular vortices.' Since there is good evidence for the beUef that 

 there is some land of rotation going on in the magnetic field, Maxwell investigated the condition of motion which 

 exists when a great number of very small portions of matter rotate on their own axes, these axes being parallel to 

 the direction of the magnetic force. The motion of these vortices does not sensibly affect the visible motions of 

 large bodies, but it can be supposed to affect the periodic motion of the medium which constitutes the phenomena 



2 S^^^y,".'" "'/I^.^ «?;P™^'*'^d his belief that the ponderable atoms vibrate, but with much smaller amplitude than the ether nartinlPQ 

 inteinational Scientific Sencs. London, 1897. "'ci painoies. 



