946 Transactions of the American Institute. 



electrical disturbance of the atmosphere brought about through 

 these spots without the usual accompanying phenomenon of aurora 

 borealis. If, as has baen conjectured, the sun revolves a vast elec- 

 trical current, the friction of its enormous surface between a posi- 

 tive and negative pole, would doubtless be sufficient to produce 

 (lie light and heat given out by that fiery orb. It would not be 

 lifficult to believe the spots on its surface caused by special ciu*- 

 rcnts of electricity to and from the various large bodies of our 

 system, and perhaps in part by the specially attractive nature of 

 metallic scoras floating upon the liquid surface below. Sun-spots 

 are frequently seen with a core of intenser blackness than the sur- 

 rounding dark portions of the umbron, as they are called. This 

 black core, known as the nucleus, if seen in space would very pos- 

 sibly be too bright to be regarded with impunity. Both nucleus 

 and umbra are thought to appear black as an efiect of contrast 

 with the dazzling electric light of the solar photosphere. The 

 question suggests itself, may not this dark nucleus indicate the 

 solid- portion of the spot, and the seat of disturbance in some of 

 the electrical phenomena which are from time to time witnessed in 

 our earth, and cannot be accounted for in other ways? The specu- 

 lation poscsses no little interest. F. L. 



The Chair would add, that the description of the display of 

 ♦jpontaneous electricity tpon telegraphic lines, quoted by this cor- 

 respondent, will excite very general interest. Admitting the 

 connection of such displays with the northern aurora and with 

 solar spots, it may be questioned whether his explanation, of the 

 phenomenon is correct. The undulatory theorj^ of light, now gen- 

 erally accepted by scientists, assumes that the interstellar spaces 

 are filled with a highly attenuated fluid (ether), Avhich, by its undu- 

 latory motion, becomes the medium of light and heat; yet recent 

 experiments seem to indicate that this ether, which doubtless also 

 fills inter-atomic spaces, as well as the so-called vacuum produced 

 by an air-pump or a mercurial column, is not in its ordinaiy state 

 a medium of electricity. Electrical force may be generated on the 

 surtace of the sun, but it is not quite apparent how such force can 

 be exerted at the distance of ninety-two or three million of miles. 

 It may be said that gravitation acts at any conceivable distance; 

 but that force is constant, while the one under consideration is 

 variable; the one is inherent in all matter, while the other is only 

 observed under certain conditions. 



