430 



SCIENCE. 



[N. S. Vol. III. No. 64. 



bined. The constitutional motion is meas- 

 ured by the force with which the atoms, 

 molecules and cells are held together as an 

 organic body. If we attempt to realize this 

 we find it very great, yet we cannot attain 

 to its measure, from the fact that it is com- 

 plicated with the heat motion of the body, 

 but we can obtain some realization of the 

 sum of the two kinds of motion, though we 

 cannot with certainty divide the molecular 

 motion between them. 



Let us first consider the velocity of rea- 

 sonably well-known molecular motion: 



Velocity of Gas Molecules. 



Meters per second. 



Atmospheric air 485 



Oxygen 425 to 458 



Nitrogen 453 to 491 



Hydrogen 1838 to 1841 



Ammonia 628 to 737 



Aqueous vapor 614 



Velocity of the Teansmission of Sound. 



Meters per second. 



In air 333 



" oxygen 317 



" liydrogen 1270 



" ammonia 415 



" water 1435 



But all of these same molecules have the 

 motion of the earth, first about its axis, 

 which at the equator is 465 meters per sec- 

 ond, and in orbit 29,606 meters per second. 

 Neglecting the motion of the earth with the 

 sun about some other point in the heavens 

 we still see that the known molecular mo- 

 tion, plus the known telluric motion, which 

 we have considered, far exceeds any molar 

 motion observed in nature or produced in 

 art. The molecular motion of a cannon 

 ball at its mouth is from 518 to 671 me- 

 ters per second. In telluric motion we 

 have the motion of bodies, and again in 

 molecular motion we have the motion of 

 bodies. The molecules themselves are com- 

 pound, and in order that the molecular 

 bodies themselves should retain their con- 

 stitution it is necessary that the motion of 



their particles should be made immensely 

 composite as correlative motions. What 

 idea can we obtain of the velocity of this 

 particle motion? Take the wooden ball 

 which we have considered and burn it and 

 we have motion as light, and light is trans- 

 mitted at the rate of 299,878,000 meters 

 per second. Here we have particle motion 

 at a velocity so great that any observed 

 molecular motion sinks into insignificance; 

 all of the ethereal motions seem to be at 

 least of rudely commensurate magnitude. 

 If the atoms are compound, as seems to be 

 indicated by a large body of evidence ob- 

 tained through chemical research, possibly 

 it may be that the particles of atoms are 

 commensurate with th& particles of ether 

 and that they have the same speed; but 

 this hypothesis is not necessary to the pres- 

 ent argument. It is only necessary to show 

 that the molecular and constitutional mo- 

 tions, together with the telluric motions of 

 every particle, are of such a magnitude as 

 to fall far within the speed of molar motion. 

 None of these motions are persistently 

 right-line motions. It is manifest that the 

 stellar motions are great revolutions. The 

 constitutional motions are also enormously 

 composite. The heat motions, though they 

 may be right-line motions in minute parts, 

 must be composite motions, their paths 

 forever changing, else the body would be 

 dissipated. The particle motion of each 

 particle in the molecule has its path con- 

 fined to the sphere of the molecule itself. 

 Considering this motion, both structural 

 and thermic, not in relation to telluric mo- 

 tion nor in relation to molar motion, but 

 wholly in relation to the particles of the 

 molecule, it must be highly composite. The 

 molar motion of the rolling ball is revolu- 

 tion and translation, but it is so small as 

 compared with the others that it hardly 

 seems worthy of consideration. Still it 

 must not be neglected, for this is the motion 

 the characteristics of which we have set out 



