190 TRANSACTIONS OF THE SOCIETY OF 



incandescent, and surrounded with a vast atmospliere ; he conceives that this 

 atmosphere, constituted chiefly of thick and metallic vapors, must be incom- 

 parably more dense than the terrestrial atmosphere, and he attributes to it the 

 protuberances and roseate border observed in total eclipses, as well as the dap- 

 pled appearance of the surface of the sun. But he denies to it the action 

 attributed by M. Kirchhoff in the production of the solar spots. 



As regards these spots, M. Gautier considers them to be connected with oxy- 

 dations, with masses of salts and scoriiB, avith solidificatious, in a word, which 

 are temporarily formed on the surface of the sun ; and this, under the influence 

 of exterior refrigeration or interior chemical action, in much the same manner as 

 is observed in great masses of metals in fusion, in our industrial operations. The 

 author admits the results of M. Spoerer and those of M. Carrington regarding 

 the apparent differences in the duration of the rotation of the sun, according to 

 the heliographic latitude of such of the spots as are adopted for the calculation 

 of this rotation. And in reference to the acceleration in longitude of the points 

 of the equatorial zone, he considers it, with our colleague M. Cellerier, as re- 

 sulting from the action exerted upon the solidified masses floating on the surface 

 of the sun, whether by the friction of the heavy and metallic atmosphere of that 

 orb, or by the interior rotary movement of the strata of its mass in fusion. These 

 two components being both a function of the velocity and of the cosine of the 

 latitude, (though this cosine has a different power for each of the two compo- 

 nents,) they vary with each parallel, and their resultant may supply the reason 

 of the acceleration in question. For the rest, although the 'author does not con- 

 sider the mean density of the sun to be inferior to that of water, yet he admits 

 that its low degree of density might form a serious objection to his theory of the 

 spots, an objection which will be met on his part by a deliberate and thorough 

 examination. 



Professor PLvUtamour read us an extract from a very interesting memoir on 

 the horary and telegraphic operations, by means of which the longitude of the 

 observatory of Neuchatel has been connected with that of the observatory of 

 Geneva. These operations have led to some new results on the employment of 

 the telegraph in determinations of this nature. But, as the paper of M. Planta- 

 mour appears in the present volume of the collection of our memoirs, we confine 

 ourselves to a simple mention of it. The same physicist presented a note on the 

 rectifications to be applied to the general system of levelling for Switzerland, 

 and on the choice to be made, as a point of departure above the sea, between the 

 mean level of the Mediterranean at Marseilles and the mean level of the ocean, 

 as the latter results from very exact measurements executed in nineteen of the 

 principal ports of France between Bayonne and Dunkirk. M. Plantamour would 

 prefer the level of the ocean, the mean of which is 0."' 80 higher than the mean 

 level of the Mediterranean at Marseilles. 



Verbal reports. — Professor Alfred Gautier presented statements, full of in- 

 terest, on several astronomical labors executed in different observatories of 

 Europe and America. These statements bore more particularly, firstly, on the 

 spots of the sun, their reciprocal occultation observed at Altona, and their pre- 

 sumed connexion with the aurora borealis and magnetic variations ; likewise, on 

 the two periods, one of eleven and the other of fifty-six years, recognized by M. 

 Wolf in the number of these spots; secondly, on the photometric researches of 

 M. Alvan Clarke, relative to the intensity of the light of the sun compared with 

 that of the fixed stars ; whence it would result that our sun cannot be one of the 

 brilliant stars of the heavens ; thirdly, on a slight augmentation to be applied to 

 the value of the parallax of Mars as hitherto recognized, an augmentation which 

 would imply that our distance from the sun is a little less than that at present 

 admitted ; fourthly, on the observation of shooting-stars by P. Secchi, from 

 which it results that these meteors are situated at a height of 100 to 150 kilome- 

 tres, and hence that they are within the limits of our atmosphere; fifthly, on 



