Briggs. } 154 [Sept. 21, 
the tube (or well) of uniform section, that is until the column reaches the 
point where the casing was blown out ; there being a great bubble of con- 
fined upper as well as a volume of confined lower gas in the bore of the 
well. Ultimately, before the column reaches the point of enlargement, the 
volumes of gas become much more considerable than those of the water. 
It may be assumed, as it is essential to do for the resulting expulsion, that 
of the 1400 feet (about) of total depth below the top of the casing not 
over 300 or 400 feet of water column (if so much) ever exists in the well. 
The water which up to this stage has ascended slowly, now rises into the 
enlarged mouth caused by theabsence of casing, and relieved from pressure 
of column, as the height reduces, the expanding gas of the upper bubble, 
becomes eruptive, and the first discharge of 3 or 4 feet height of water is 
effected. The relief of pressure attendant upon the removal of a portion 
of the water above into the pool, lifts the lower column of water to above 
the upper gas bearing strata; but before it reaches the enlargement at the 
casing the force of expulsion of the upper hybble will have been expended, 
and the water thus discharged will have returned wholly or in part to the 
well again, and will have restored the original column and its pressure 
upon a larger volume of gas with the supply of both gas bearing strata. 
The regular supply of gas continuing, the column again reaches the point 
of enlargement, and now, with a great reservoir of gas to expand, the final 
effort of a pulsation is consummated, with a discharge of gas and water of 
85 to 115 feet in height. Allowing for the mixture of gas and water in 
reducing the gravity of the column, it is possible that the greatest pulsation 
of emergence at the mouth of the well cannot be more than the equivalent 
to a height of 60 to 90 feet or 30 to 45 pounds per square inch. 
In the case of the Geyser the same necessity of conformation of the pit 
or hole, so far as regards the funnel-shaped mouth to relieve the pressure 
of water column at or near the top, exists. The heated water is then the 
reservoir of energy for producing an eruption ; a large volume of steam 
being formed at once when relief of pressure occurs. The phenomena of 
periodic discharge following a course similar to that described as coming 
from emission of gas from a strata when the cooled return water comes in 
contact with the volcanic heated rocks at the bottom of the hole, producing 
a steam pressure more rapidly than the water circulation will permit the 
heat to be transferred to the surface of the water quietly and thus lifting 
the column to the point of enlargement where its pressure is reduced. 
