of Edinburgh^ Session 1883-84. 
491 
measuring hardly 0'2 mm., generally they are smaller, their surface 
is quite covered with a brilliant black coating having all the properties 
of magnetic oxide of iron, often there may be noticed upon them cup- 
like depressions clearly marked. If we break down these spherules 
in an agate mortar, the brilliant black coating easily falls away and 
reveals white or grey metallic malleable nuclei, which may be beaten 
out by the pestle into thin lamellse. This metallic centre, when 
treated with an acidulated solution of sulphate of copper, immediately 
assumes a coppery coat, thus showing that it consists of native iron. 
But there are some malleable metallic nuclei extracted from the 
spherules which do not give this reaction ; they do not take the 
copper coating. Chemical reaction shows that they contain cobalt 
and nickel j very probably they constitute an alloy of iron and these 
two metals, such as is often found in meteorites, and whose presence 
South Pacific. 
in large quantities hinders the production of the coppery coating on 
the iron. G. Eose has shown that this coating of black oxide of 
iron is found on the periphery of meteorites of native iron, and its 
presence is readily understood when we admit their cosmic origin. 
Indeed, these meteoric particles of native iron in their transit 
through the air must undergo combustion, and, like small portions 
of iron from a smith’s anvil, be transformed either entirely or at the 
surface only into magnetic oxide, and in this latter case the nucleus 
Fig. 2, — Black Spherule with 
Metallic Nucleus (^). This 
spherule covered with a coat- 
ing of black shining mag- 
netite represents the most 
frequent shape. The de- 
pression here shown is often 
found at the surface of these 
spherules. From 2375 fins. 
Fig. 3. — Black Spherule with 
Metallic Nucleus (^). The 
black external coating o 
magnetic oxide has been 
broken away to show the 
metallic centre, represented 
by the clear part at the 
centre. From 3150 fms. 
Atlantic. 
