Section of Meteorite showing Widmannstättian Lines.

(Field Columbian Museum, Chicago.)

Meteorite, Toluca.
(Field Columbian Museum, Chicago.)

In them prove to be occluded gases, which can be got out by heating in the laboratory, and which must have got in when the meteorites were still subjected to great heat and pressure. For only thus could these gases have been absorbed. Both such heat and such pressure accuse some great solid body as origin of this flotsam of the sky. Fragments now, they owe to its disruption their present separate state. This parent mass must have been much larger and more massive than the Earth, as the grate amount of occluded hydrogen, sometimes one-third the volume at 500° C., of the meteorite seems to testify.

The two classes of meteorites, the stone and the iron, show this further by the very differences they exhibit between themselves. For both the amount and the proportions of the occluded gases in the two prove to be quite distinct. In the stones the quantity of gas is greater and the composition is diverse. In the stones carbonic acid gas is common, carbon monoxide rare; in the irons the ratio is just the other way. Thus Wright found in nine specimens of the iron meteorites:—

CO₂ COHCH₄
11.5%32.4%54.1%00% of the total;