. CarrutuEers.—Retardation of Earth’s Rotation by Volcanic Action. 865 
how their effects may be felt over only a few square miles. At the moment 
of this earthquake the voleano, at the foot of which Mendoza was situated, 
burst into eruption. 
On the other hand, in February, 1797, when Riobamba was destroyed 
by an earthquake, the voleanoes of Cotopaxi and Tunguragua, at the foot 
of which the town was situated, were not in the least influenced, while 
Pasto, at a distance of 120 miles, “‘ suddenly ceased to throw up its habitual 
column of water.” 
When the great earthquake visited Chili in 1835, its three great vol- 
canoes burst into activity, and continued eruptive for months, while during 
the earthquake at Valdivia, in 1822, the neighbouring volcanoes were 
active for a few minutes only. 
In 1772 a Javanese volcano, Papandayung, burst into activity. At the 
same moment two other volcanoes, distant respectively 184 and 852 miles, 
also became active, while many intervening volcanic cones remained undis- 
turbed. 
When, in 1843, Mauna Loa, one of the Sandwich Island volcanoes, was 
in violent eruption, the neighbouring permanently active crater of Kilauea, 
only fifteen miles distant, remained in its normal state. 
To account for these and other facts the central fire theory has to be 
modified by most extraordinary suppositions, all, of course, resting on no 
foundation whatever. 
First astronomers showed that the original idea was incorrect that the 
solid crust of the earth is very thin; it was shown that a less thickness 
than 400 miles would not accord with the observed precession of the equi- 
nox. Mathematicians also showed that the earth would not cool in the 
manner assumed, that is, only atthe surface. It was then found that even 400 
miles were too little for the thickness of the crust, and that 800 miles were 
necessary. This made it very difficult to believe that two pipes 800 miles 
long leading down to the fluid centre, could exist within fifteen miles of each 
other, and still be independent, as was necessary to account for the fact 
that Kilauea was not influenced by the eruption of its neighbour, Mauna 
Loa. A new disposition of the fluid matter was then devised, by which it 
was supposed to be placed as a fluid shell between a solid outer crust and 
a solid centre. 
The fluid shell was then supposed to be divided by walls of lava into 
separate channels, each crater having a connection with its own channel ; 
Mauna Loa and Kilauea, for instance, were not connected with the same 
channel. Papandayung, and the other two volcanoes which broke out at 
the same time with it, were supposed to be connected with the same 
channel, while the intervening craters were connected with different ones. 
