not been seen in action since.

Dr. Peal finds the theories advanced for the generation of steam
unsatisfactory and insufficient, especially in the class of geysers
having a long steam period. He says: (page 423)

"The Castle Geyser differs from Old Faithful and the Bee Hive mainly in
the fact that it has a long steam period, during which the steam pours
out or is pushed from the geyser throat with great violence and a
terrific noise. There appear to be only two possible explanations of
this difference, viz., either an accumulation of immense volumes of
steam in the Castle, or an instantaneous formation of steam throughout
the length of the geyser tube. The former, to our mind, is untenable,
because it seems impossible that the water, which is exhausted in
fifteen minutes, should exert enough power to keep down the immense
amount of steam that escapes for more than an hour. According to
Bunsen's theory, it can be readily explained. The relief afforded by the
first part of the eruptions allows the superheated water to rise
rapidly, and before it can reach the top or orifice of the tube it is
all converted into steam from the top downward with inconceivable
rapidity, and must be forced out with the terrific violence which is
noted in the case of the Castle. On page 208 we have expressed the
opinion that it is the oldest geyser in the region, and it seems to us
that a greater length in the tube, with a consequent greater supply of
water, will account for the difference between the Castle and Old
Faithful, the latter of which we consider one of the youngest geysers in
the Upper Geyser Basin."

A study of the Caves in connection with the active Geysers indicates
that the theory he suggests and then rejects, is probably the true
explanation of the difference between the two kinds of geysers. It seems
that the length of the tube must necessarily have more effect on the
height of the jet than on the generation of steam; as after an eruption
the tube is hotter than at any other time and therefore the generation
of steam in it should be less than usual, unless the fresh inflow of
water was cold. Then if the storage cavities are broad but low, the
steam cannot accumulate above the water; but when the pressure becomes
sufficient to force a passage through the tube, the water and steam are
expelled together until the pressure is exhausted. But if the storage
chambers are vertical fissures, as Wind Cave illustrates, vast
quantiti