sulphuric acid. Thus:

CaCO_{3} } { CaSO_{4}.H_{2}O (gypsum)
H_{2}S, } yield { and
2H_{2}O, } { CH_{4}, which is marsh gas.

And

2CaCO_{3}, } { 2CaSO_{4}.H_{2}O
2H_{2}S, } yield { and
2H_{2}O_{2}, } { C_{2}H_{4}, which is _ethylene._

Tables are given showing the formulæ for the homologues of ethylene
and marsh gas resulting from the increase in regular gradation of the
same constituents.

_Formulæ Showing how Ethylene and its Homologues
(C_{n}H_{2}{n}) are Produced by the Action of the Volcanic
Gases H_{2}S and H_{2}O_{2} on Limestone._

Carbonate Sulphureted Peroxide of Ethylene and
of lime. hydrogen. hydrogen. Gypsum. its homologues.

2CaCO3 + 2H2S + 2H2O2 yield 2(CaSO4.H2O) + C2H4 ethylene
(gaseous).
3CaCO3 + 3H2S + 3H2O2 " 3(CaSO4.H2O) + C3H6
4CaCO3 + 4H2S + 4H2O2 " 4(CaSO4.H2O) + C4H8
5CaCO3 + 5H2S + 5H2O2 " 5(CaSO4.H2O) + C5H10
6CaCO3 + 6H2S + 6H2O2 " 6(CaSO4.H2O) + C6H12
Boiling