Geological Society. 239 



A Table was then given, showing the relative position of sun-spots 

 and their accompanying faculse for all the Kew pictures available 

 for this purpose. 



From this it appeared that out of 1137 cases 584 have their 

 faculae entirely or mostly on the left side, 508 have it nearly equal 

 on both sides, while only 45 have it mostly to the right. It would 

 thus appear as if the luminous matter being thrown up into a 

 region of greater absolute velocity of rotation fell behind to the left ; 

 and we have thus reason to suppose that the faculous matter which 

 accompanies a spot is abstracted from that very portion of the sun's 

 surface which contains the spot, and which has in this manner been 

 robbed of its luminosity. 



Again, there are a good many cases in which a spot breaks up in 

 the following manner. A bridge of luminous matter of the same 

 apparent luminosity as the surrounding photosphere appears to cross 

 over the umbra of a spot unaccompanied by any penumbra. There 

 is good reason to think that this bridge is above the spot ; for were 

 the umbra an opaque cloud and the penumbra a semi-opaque cloud, 

 both being above the sun's photosphere, it is unlikely that the spot 

 would break up in such a manner that the observer should not per- 

 ceive some penumbra accompanying the luminous bridge. Finally, 

 detached portions of luminous matter sometimes appear to move 

 across a spot without producing any permanent alteration. 



From all this it was inferred that the luminous photosphere is 

 not to be viewed as composed of heavy solid, or liquid matter, but 

 is rather of the nature either of a gas or cloud, and also that a spot 

 is a phenomenon existing below the level of the sun's photosphere. 



The paper concluded with theoretical considerations more or less 

 probable. Since the central or bottom part of a spot is much less 

 luminous than the sun's photosphere, it may perhaps be concluded 

 that the spot is of a lower temperature than the photosphere ; and 

 if it be supposed that all the sun's mass at this level is of a lower 

 temperature than the photosphere, then we must conclude that 

 the heat of our luminary is derived from without. 



GEOLOGICAL SOCIETY. 



[Continued from p. 159.] 

 December 21, 1864.— W. J. Hamilton, Esq., President, 

 in the Chair. 

 The following communications were read : — 

 1. " On the Coal-measures of New South Wales, with Spirifers, 

 Glossopteris, and Lepidodendron." By W. Keene, Esq. Communi- 

 cated by the Assistant- Secretary. 



The prevailing rock in New South Wales is a sandstone, which 

 is called the " Sydney Sandstone " by the author, and is the most 

 recent deposit in the colony. Its upper beds contain certain shales, 

 called the "False Coal-measures" by Mr. Keene, and the " Wya- 

 namatta Beds " by the Rev. W. B. Clarke, the position of which is 

 800 feet above the true Upper Coal-seam. On approaching the 

 latter, Vertebraria australis and Glossopteris are met with ; and these 



