32 AMERICAN MUSEUM GUIDE LEAFLETS 
presence of from 8 to 10 per cent of stony matter included in the nickel- 
iron, and the proportions of the mineral constituents vary considerably 
in different parts of the mass. ‘The nickel-iron is an alloy consisting 
of 89.89 per cent iron, 9.58 per cent nickel, 0.49 per cent cobalt and 0.04 
per cent. copper, while the stony matter consists of olivine, carrying an 
unusual quantity of lime and associated with noteworthy quantities of 
schreibersite and chromite. 
BRENHAM. 
(Siderolite. ) 
Brenham is classed as a siderolite, but some of its fragments are 
entirely of nickel-iron. ‘The etched section shown in the Foyer illustrates 
clearly the peculiar texture of the mass. ‘The metallic portions consist 
BRENHAM 
Siderite (left) and Siderolite (right) in the same piece. 
of about 88 per cent. iron, 10 per cent. nickel and 2 per cent. other sub- 
stances. ‘The dark green and glassy portions are crystals of olivine, 
which break out from the iron almost entire. 
