338 ANNUAL OF SCIENTIFIC DISCOVERY. 



all kinds ; so that its lower strata ought to be comparatively heavier 

 than those of the terrestrial atmosphere. As the rotatory motion of the 

 central globe cannot be supposed to be transmitted to its gaseous 

 envelop so far as its most elevated limits with the same angular veloc- 

 ity, the solar atmosphere is probably susceptible of exercising on the 

 liquid surface an action analogous to that of friction. 3. The emana- 

 tions or metallic vapors surrounding the sun, and impregnated with 

 dust, smoke, or lava, form around it a layer of variable thickness, and 

 present total eclipses, the appearance of red borders and protuber- 

 ances. 4. The solar dark spots are partial solidifications. of the 

 surface, due either to cooling or to chemical action, reuniting 

 momentarily into aggregates, salts, or oxyds, which have issued from 

 the mass in fusion, and float on its surface. 5. The faculae (bright 

 spots) are the result of the appearance on the sun of very brilliant 

 substances, endowed with radiating power. 6. The acceleration 

 observed in the rotatory movement of the spots situated near the solar 

 equator is the result of the exterior action of the atmospheric pressure 

 on the liquid surface, combined with that of the interior layers of the 

 mass in fusion. Accidental irregularities may proceed from the dis- 

 turbance of the chemical and physical equilibrium of the various 

 materials composing the mass. 



In a paper on this same subject, recently read by Mr. Dawes to the 

 Royal Astronomical Society, he stated that " the mottled surface of 

 the sun can be seen with a low power." It has been variously de- 

 scribed, and it appeared to him in many ways ; but he stated that he 

 had not been able to verify the appearance of the " willow leaves " 

 described by Mr. Nasmyth. Mr. Dawes considers Sir John Her- 

 schePs words, " the surface is like some flocculent chemical precipitate 

 slowly settling down, 11 to be by far the best description of the solar 

 disc. When Mr. Dawes used a very small perforation, with an eye- 

 piece of high powers (400 to 600), he rarely saw much change in the 

 pores, except in the vicinity of the spots, which were rapidly expand- 

 ing or closing, when the appearance of the surface at the margin 

 resembled small bits of straw or thatching, interlacing in all directions. 

 He says that with regard to the spots in the black centers, distinction 

 ought to be made between the umbra and the nucleus. The exist- 

 ence or absence of this black central portion may possibly determine 

 the origin of the spots. 



TEMPERATURE AND CLIMATE OF THE MOON. 



Mr. James Nasmyth of England, in a recent lecture before the 

 Royal Institution, on the above subject, dwelt on the great evidence 

 of volcanic action in the formation of the moon's surface, and ex- 

 pressed his own conviction that all volcanic action is of cosmical 

 origin and as ancient as the planets themselves ; the heat being essen- 

 tially different from that of ordinary combustion, which required the 

 presence of oxygen. The bulk or solid contents of the moon, as 

 compared with that of the earth, is as 1 to 49. The surface of the 

 moon, as compared with that of the earth, is as 1 to 16. On the sup- 

 position that the moon and the earth were formed at the same period, 

 by the condensation of nebulous matter, the rapidity of the cooling of 

 the moon would be four times as great as that of the earth, in conse- 



