No. 4.— Conditions and Effects of the Expulsion of Gases from 
the Earth. v 
By N. S. Siialer. 
In an incidental way geologists have long remarked the facts 
connected with the expulsion of gases and vapors from the depths 
of the earth. These facts have been made familiar by the study of 
volcanic and solfataric actions as well as by the phenomena exhibited 
by springs which send forth their waters under the impulse of 
gaseous pressure. So far as I am aware, however, no one has 
undertaken to group certain of these exhibitions of the effects of 
elastic tensions in a manner which may be seen to show their gen¬ 
eral order. To effect this grouping is the aim of this paper. In 
this task I shall first consider the curious phenomena connected with 
the escape of gases from open-textured rocks during earthquakes of 
considerable intensity. In this connection the development of 
certain groups of ordinary springs will be taken up, and finally the 
likeness of these lesser manifestations of internal gaseous actions to 
those developed in volcanic action will be discussed. The central 
aim of the writing is to indicate certain general features probably 
related in causation which characterize all these methods of expul¬ 
sion of gases from the earth. 
Ever since we began to have detailed narratives of earthquakes 
the records have abounded in accounts of the way in which the 
earth during the movements opened, spouting forth more or less 
considerable quantities of water. In general these stories are con¬ 
fused, after the manner of the stories told by untrained observers. 
From the most of them we can gain no clear idea as to the form 
of the openings or the way in which the escape of the water was 
brought about. Of late, however, the studies which have been 
made on earthquake phenomena have shown that ejections of water 
take place in a violently shaken field under either of two conditions, 
by the opening and closing of elongated fissures or rents and by the 
formation of vertical, more or less cylindrical channels which lead 
from a considerable depth and which are opened coincidentally 
with the escape of jets of water. 
