' ASTRONOMY AND METEOROLOGY. 323 



out proof, though still among the unrevealed mysteries of nature, may 

 finally submit to unremitting researches. For instance, the solar spots 

 can now be safely pronounced to be no longer an object of idle curiosity, 

 like the casual clouds of our atmosphere. The few land-marks hitherto 

 recorded begin to indicate a regular progress of position in them, with 

 periodical maxima and minima in their amount. Thus, in the years 

 1845-46, the groups of solar spots extended to about 40 north of the 

 equator, and to 30 south of it, leaving a central blank band from 8 

 north to 5 south. This state of arrangement is now recurring, with 

 the exception that the preponderance is at present on the south side of 

 the equator. In 1853 and 1854, the spots wqre distributed from 20 

 north to about 20 south, decreasing in number till early in the year 

 1856, when there was a decided minimum, and the equatorial region 

 remained clear ; but spots appeared in both hemispheres from 20 to 

 40. Their parallels are already again contracting. So much for their 

 position, and now for their motion. Their daily drift in longitude re- 

 veals a general equatorial current 30 in breadth, in the direction of 

 the rotation, and a reverse current of nearly the same breadth is per- 

 ceptible beyond it, in each hemisphere. The observations of Gen. 

 Sabine have also established a correspondence between solar and ter- 

 restrial magnetic disturbances extending through a decennial period, 

 and also another connected with the earth's orbit. M. Dawes has also 

 noticed the rotation of a remarkable spot on the sun's disc, to an extent 

 of an arc of 100 in six days. 



Distribution of Heat on the Sun's surface, and the Currents in his at- 

 mosphere. - - Secchi, of Rome, has ascertained that the sun's equator 

 is sensibly hotter than its poles. That this should be the case, follows 

 from the meteoric theory of solar heat. The asteroids which revolve 

 round the sun and are supposed to fall into its atmosphere as meteors, 

 probably occupy, like the entire solar system, a lenticular space having 

 its greatest diameter nearly coincident with the sun's equator, and if 

 so, a greater number of meteors must fall on the equatorial than on the 

 polar regions of the sun, making the former the hottest. The meteoric 

 theory will also account for the currents in the sun's atmosphere ob- 

 served by Mr. Carrington. He finds that the spots in the lowest lati- 

 tudes drift most rapidly from W. to E. Were the sun's atmosphere, 

 like the earth's, acted on by no other motive power than the one equal 

 heating of different latitudes, the relative direction of the currents 

 would be the reverse of this, in virtue of the well-known principles of 

 the trade-winds and " counter-trades," and this would be true at all 

 depths in the sun's atmosphere. But if meteors are constantly falling 

 into the sun's atmosphere, moving from west to east with a velocity 

 scarcely less than that of a planet at the sun's surface, and in greatest 

 number in its equatorial regions, there is a motive power which is ade- 

 quate to drive its atmosphere round it from west to east, and with 

 greatest velocity at the equator. The intensely bright meteor-like 

 bodies which Mr. Carrington and another observer simultaneously saw 

 traverse the sun's disc, moved from west to east, and they were almost 

 certainly asteroids falling into the sun. 



Daily Photographs of the Sun's Disk. At the Kew Observatory, 

 England, two photographs of the sun's disk are taken daily (atmospheric 

 conditions permitting), one to the east and the other to the west of the 



