which fell near Adair, in the County of Limerick. 29 



And the insoluble portion, B, yielded, 



Silex 32.11 



Protoxide of iron and oxide of chrome 5.91 

 Magnesia and a little lime . . . 9.43 



47.45 



If then we exclude the pyrites, the following will be the component parts of 

 matrix of meteorite : — 



Silex 32.11 



Oxides of iron, nickel, cobalt, and 1 



\ 13..53 

 chrome j 



Magnesia, with a little lime . . . 22.81 



68.45 



But 



= 1.10 



36 

 22.81 



20.7 



Hence, the number of atoms of silex in the matrix of the stone is to the sum of 

 the numbers of atoms of protoxide of iron and of magnesia, as 2.07 to 0.37+1.10, 

 or as 3 to 2.13. Now, as the atom of lime is greater than that of magnesia, and as 

 the oxide of chrome and its associated iron do not exist in combination with silex, 

 the latter number, 2.13, must be a little too high, so that the decimal part, at least, 

 may be safely omitted. The number of atoms of silex will thus come out to be 

 to the sum of the numbers of atoms of the bases with which it is combined, as 

 3 to 2 ; so that the stone is composed of an atom of a silicate, associated with an 

 atom of a bisilicate, or, in other words, of an atom of olivine united to an atom of 

 pyroxene. That such is the true composition of the portion of the meteorite 

 under consideration, there can, I conceive, be no question, for the matrix is ob- 

 viously composed of two distinct minerals, one of which, like olivine, is soluble, 

 and the other, like augite. Insoluble in the acids. 



