September 11, 1903.] 



SCIENCE. 



:i:V> 



discussed, he will admit that his points are 

 well artrued and that the book has given him 

 a clear outlook upon the broad subject of mu- 

 nicipal works. 



George C. Whipple. 



DliiCLSSIOy AXD CORRESPOXDEXCE. 



ELECTRICITY .\T HIGH PRESSURES. 



To THE Editor of Science: Some three or 

 four years ago* I put forward the idea that 

 just as with increase of vacuum and potential 

 the Roentgen rays become more and more 

 l)enetrating, there may possibly be produced, 

 when cathode ray ions (electrons) move with 

 the very highest velocities, rays that penetrate 

 considerable thicknesses of nearly all bodies 

 without undergoing absorption. Interstellar 

 sjjace may be traversed not only by light and 

 heat waves, but also by rays of the more re- 

 cently discovered penetrating kinds including 

 those of extreme penetrating powers above 

 assumed as possible. 



From what source would such highly pene- 

 trating rays as are referred to come? Might 

 they not come from matter (electrons or as- 

 semblages of electrons called atoms, or even 

 small masses of matter) moving with such 

 very high velocities as are somewhat com- 

 parable with the velocity of light? These 

 assemblages of electrons on impact would 

 probably give Roentgen rays of all orders up 

 to the very highest or most penetrating. Such 

 rays would be absorbed only in larger or 

 denser masses of matter and the absoiijtion 

 would ordinarily be undiscoverable. The ce- 

 lestial bodies, as the stars, planets, etc., would 

 probably absorb the rays, and the rays in being 

 so absorbed would add energy to the masses, 

 tending to some extent to keep up their tem- 

 perature. 



The natural question arises as to whether 

 there are any existing conditions under which 

 the smallest particles could attain high veloci- 

 ties. When an extremely minute particle of 

 matter near the sun or in the outer envelope of 

 gas around the sun is of a nature to absorb the 

 radiation, a radiation pressure will be e.xerted 



Electricity at High Pressures,' lecture before 

 tlie New York Electrical Society, March 29, 1899. 



upon it which may, if the particle is small 

 enough, be in excess of gravitational force. 

 Such particles continuously expelled, in vir- 

 tue of the excess of radiation pressure over 

 gravitation, may give rise to the coronal 

 streamers around the sun. If the condition 

 just pointed out be possible, the particle will, 

 under the difference of force, be accelerated 

 outwardly from the sun, and continue to move 

 away with an acceleration which, though 

 diminishing, is still an acceleration. Such 

 particles would naturally be expected to leave 

 or be driven away from any hot star. 



That a particle once started away will con- 

 tinue moving outwardly with an acceleration, 

 follows from the fact that both the radiation 

 pressure and gravitation vary as the inverse 

 squares of the distances. This means that if a 

 particle is moving towards the sun under the 

 influence of gravitation, it will not at any 

 time be stopped by the radiation pressure un- 

 less it be subdivided into smaller particles. 

 It also means that any set of particles moving 

 from the sun under radiation pressure in ex- 

 cess of gravitation must continue forever mov- 

 ing away, unless such particles are brought 

 together into large masses or collide with other 

 masses. It is possible that the limiting veloc- 

 ity which could be attained would be the speed 

 of light waves in the etlier. Such rapidly 

 moving particles, whether consisting of many 

 molecules or atoms (groups of electrons) or 

 consisting of separate electrons or ions would 

 probably, on striking other particles or masses, 

 give out intense radiation of the Roentgen 

 ray order, and accompany the same by heat 

 radiation, or visible radiation, or both. Such 

 particles might even serve to illuminate some 

 of the apparently cold nebula;, either by the 

 impact generating heat and light, or by fluor- 

 escence. 



Here, then, is the outline of a new cor- 

 puscular theory of energj' conservation, which 

 is not the Newtonian corpuscular theory, but 

 which supplements the undulatory theory in 

 providing a mode of recovery for at least a 

 portion of the energy of radiation. Any 

 particle which is set in motion by the radia- 

 tion pressure is within limits converting the 

 energy of radiation into mechanical move- 



