40 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



ellipse, having a diameter of a third of a second, which lat- 

 ter is, at a distance of 5.5 seconds, carried uniformly about 

 the point central between A and B. Bullet. Ilebdomadaive 

 Assoc. Seientijlque, 1875, 217. 



OX THE CHEMISTRY OF THE SOLAR SYSTEM. 



Observation and theory have led Lockyer to the conclu- 

 sion that the various elements constituting the sun are ar- 

 ranged in layers according to the atomic weight of their 

 vapors. Thus outside of all is hydrogen, with an atomic 

 weight of one. Then follow, in regular order, magnesium, 

 calcium, sodium, chromium, manganese, iron, nickel, etc. At 

 the centre the nobler and rarer metals must be found, consti- 

 tuting the substance of the sun. In this same order should 

 the nebulous mass have been arranged from which the solar 

 system was developed, according to La Place's hypothesis, 

 consequently the exterior planets of the solar system should 

 be principally formed by the condensation of the metalloids, 

 and the inferior planets be composed of the metallic ele- 

 ments ; thus Lockyer explains the feeble specific gravity 

 of the former, and the greater mass of the latter planets. 

 The composition of the atmospheres of the planets, which 

 give only a few rays of absorption in the spectrum, seem 

 to confirm this view of Lockyer. Even the composition of 

 the outer shell of the earth would seem to accord therewith, 

 since it is formed in the following proportion : Oxygen, 500 ; 

 silicium, 250 ; the other metalloids, 227 ; and of other simple 

 bodies, 23 parts out of a thousand. If, on the other hand, we 

 add the liquid portion of water, it will be found that hydro- 

 gen enters in a still larger proportion, and, with oxygen, ac- 

 quires a predominance; so that it may be said our earth is 

 composed principally of oxygen and hydrogen, with a small 

 percentage of metals and metalloids. La Nature, III., 20G. 



A FAMOUS SOLAR ECLITSE. 



The total solar eclipse of the 3d of June, 1239, was a 

 memorable event in Central Europe, and has formed the 

 subject of an interesting memoir by Celoria, one of the as- 

 tronomers at the Observatory of Milan. This gentleman 

 lias collected together all the accessible notes with reference 

 to observations made at that time upon the eclipse, from 



