A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS. 417 
The remaining metallic iron was more rich in nickel than before, and con- 
tained, besides, the sulphuret of iron combined together with the phosphuret, 
in the form of the triple phosphuret of iron, nickel, and magnesium (disco- 
vered in meteorites by Berzelius), which was separated from the iron by acid 
in metallic-looking grains. 
A synthesis of the chief ingredients of aérolites being thus found possible 
without the use of reducing agents, M. Daubrée is finally disposed to adopt 
the opinion that aérolites originally underwent a process of scorification, 
accompanied by incomplete oxidation, or a species of natural cupellation*, in 
which the substances having most avidity for oxygen were first completely 
oxidized, and the less chemically active elements and metals remained partly 
in the uncombined state, or alloyed with each other. The complete analogy, 
which this view presents to the generally received opinion regarding the 
formation, by oxidation, of the earth’s crust, recommends its unreserved 
adoption as the description of a cosmical process only differing from that 
recognized on the earth by its particular degree of completeness or duration. 
The highly oxidized materials, the absence of metallic iron, and the con- 
version of phosphurets and sulphurets in the earth’s crust into phosphates 
and sulphates, may be considered to have resulted from the same process of 
scorification, accompanied by a far more advanced oxidation than that con- 
cerned in the formation and metamorphoses of meteorites. 
In a later reprint of the same paper; M. Daubrée gives the following 
Table of the specific gravities of eruptive rocks and basalts, showing the su- 
perior gravity of peridot to all of them, closely approaching the ordinary 
specific gravity (3°35) of aérolites ;— 
Granite...... 2:64-2:76 Basalt...... 2-9-3:1 
Trachyte .... 2:62-2:88 Enstatite... 3°303 
Porphyrite... 2°76 Lherzolite .. 3:25-3:33 
Diabase. .... 2:66-2:88 Peridot .... 3:33-3°35 
Continuing his researches on the composition of aérolites t, a new classi- 
fication of aérolites, founded on the amount and mode of distribution of 
metallic iron in them, was suggested. The process adopted for this classifi- 
cation was proposed by M. 8. Meunier, and resembles that commonly em- 
ployed in the extraction of metallic gold from its matrix in quartz rocks. A 
fragment of the aérolite, supported by an iron wire, is heated to redness in 
a current of carbonic acid gas, and while still red-hot it is suddenly chilled 
by plunging into mercury. The siliceous portions of the aérolite are then 
easily crushed out from the interstices of the iron, and the mode of distribu- 
tion of the latter is most clearly distinguished: 1°, when the mass of iron is 
solid, the meteorite is termed a Siderite ; 2°, when it forms a continuous net- 
work in which the siliceous matter is included or interlaced, the meteorite 
is a Syssiderite ; 3°, when the iron forms separate grains, or is discontinuous, 
“as generally occurs in aérolites, the meteorite is a sporado-siderite; 4°, 
Cryptosiderites are those which exhibit a total absence or only very doubtful 
traces of metallic iron. In the Syssiderites of Pallas and Atacama the 
siliceous parts are discontinuous; but in that of Rittergriin they form, like 
the iron itself, a continuous mass, interwoven with the iron, 
* An expression used by M. Elie de Beaumont to describe the same process as it is 
supposed to have originally operated on the earth (Bulletin de la Société Géologique de 
la France, 1847, 2nd ser. vol, iv. p. 1326), 
+ Ibid. 2nd ser. vol. xxiii. p. 408, March 5, 1866. 
} Comptes Rendus, vol. lxv. pp. 60, 148 (July 22, 1867). 
