G. P. Merrill — Composition of Stony Meteorites. 471 



and the proper interpretation to be put upon the same, add to 

 the difficulties. Several of the constituents, moreover, occur 

 in such extremely small quantities, or like the chloride of iron 

 (lawrencite), undergo such rapid deterioration, that their deter- 

 mination has been largely overlooked, particularly' in the older 

 analyses. Or, again, if such determinations were made, the 

 results as given are at least open to doubt in the light of more 

 recent investigations. In or>inp; over all of the literature 

 available, I have found but ninety-nine analyses which were 

 made, as it seemed to me, with sufficient care, were sufficiently 

 complete, or stated in such a way as to render the results com- 

 parable with one another. Even in these ninety-nine, all of 

 the constituents were not determined, and in many instances, 

 where the presence or absence of a certain element was not 

 stated, one is left in doubt as to whether such was looked for, 

 or whether it was looked for and found lacking. Out of the 

 ninety-nine analyses, however, silica, alumina, iron, ferrous 

 oxide, lime, magnesia, potash and soda were found determined 

 in a sufficient number of cases to make the matter of an aver- 

 age a fairly safe approximation, the metallic iron affording the 

 most difficulty. Of the remaining constituents, as given in the 

 table below (No. 1), the manganese is an average of forty- one 

 determinations, the phosphorus of thirty-one, the chromic iron 

 of sixty-seven, the sulphur of ninety-two, and the nickel- cobalt 

 of ninety-three. The percentage amount of sulphur has, in 

 many cases, been arrived at by calculation, since the results 



Average composition of stony meteorites as calculated from 99 analyses 

 for all constituents but P, which is from 31 determinations ; MnO 

 from 41 determinations, Cr 2 3 + Fe 2 03 from 67 determinations; Ni,Co 

 from 93 determinations ; and S from 92 determinations. 



I II 



Average of Eecalculated on 



Eesults as given basis of 100 



Si0 2 38-98 38-732 



Al 2 O s 2-75 2-733 



Fe 11-61 11-536 



FeO 16*54 16-435 



CaO... 1-77 1-758 



MgO 23-03 22-884 



Na o 0-95 0-943 



K 2 0-33 0-328 



CrO +FeO ... 0-84 Av, 



Ni,Co._. 1-32 



S l-85» 



P... ._.. o-u 



MnO.. 0-56 



of 67 dets. 0-835 



' 93 " 1-312 



' 92 " 1-839 



' 31 " 0-109 



1 41 " 0-556 



100-64 100-00 



