336 Mr. P. E. Chase on Gravity and Magnetic Inclination. 



still more satisfactory when viewed in connexion with the gravi- 

 tation-disturbances, I will briefly refer to some of the more im- 

 portant points that have helped to confirm me in the various 

 views that I have hitherto advanced. Such are, e. g., the evi- 

 dences of the identity of helices and magnets (2239) ; the exist- 

 ence of magnetic repulsion without polarity (2274) ; the relative 

 magnetic position of gases and vapours (2416) ; the relations of 

 the magnecrystallic, cohesive, and magnetic forces (2479, 2562, 

 2578) ; the probable dependence of the magnetic motions of 

 fluids upon their mass and density (2768, 2769, 2781, 2863); 

 the magnetic influence of winds and varying atmospheric pressure 

 (2952, 2954) *; the supposed velocity of magnetic transmission 

 in [space or aether (2958) ; the daily bipolar minima of cold 

 (3006) ; the closed circuits and prominent characteristics of the 

 magnetic lines of force (3117, 3278, 3279, 3284) ; the tendency 

 of all bodies to evolve electric currents when moving in a mag- 

 netic field (3337) ; the relative diamagnetic and magnetic effects 

 of heat and cold upon air and the diamagnetic gases, as well as 

 upon iron, nickel, and cobalt (2861, and III. pp. 446, 460, 464, 

 472, 473, 489, 490). 



It should not be forgotten that there is no such thing within 

 the compass of our observation as i( potential " gravity, no in- 

 stance of matter in absolute rest, and just beginning or tending 

 to move under a gravitating pull. Every particle of the earth, 

 independently of the action of heat, chemical affinity, and cohe- 

 sion, is at every instant subjected to four principal and important 

 impulses — two toward the centres of the sun and earth respec- 

 tively, and two tangential to the earth's orbit and to its circum- 

 ference. Of the several motions, the orbital one is by far the 

 most important. Next in point of velocity is the one tangential 

 to the circumference ; in point of intensity, the one toward the 

 centre of the sun. Since the solar central and tangential motions 

 are in aquilibrio, it seems eminently proper that the others should 

 be regarded as disturbances, which tend, as I have elsewhere 

 shown, to give a daily ellipticity to each section of air parallel to 

 the equator. Not only are the barometric daily tides a necessary 

 consequence of such ellipticity ; owing to the difference of specific 

 gravity, the cold air, in addition to the proper motion of convec- 

 tion, is alternately drawn toward and repelled from the earth's 

 surface ; and I am inclined to believe that many of the pheno- 

 mena of the deposition of dew and the magnetic perturbations, 

 which cannot be explained by other more important gravitation- 

 currents, may be thus accounted for. 



* Humboldt speaks of the accumulation of electricity in the lower equi- 

 noctial regions, "at the maximum of heat, and when the barometric tides 

 are near their minimum." (Taylor's i Scientific Memoirs/ vol. iii. p. 398.) 



