at Its very highest pitch, did not throw the
column of water above eighty feet; Avhile, bv
other travellers, it is stated to have been
as
u n d e r:—
Olafsen aud Povelsen
Von Troil . . . .
Sir John Stanley (by a quadrant)
Dr, Ilooker
Sir George Mackenzie
Mr. Henderson
F cet.
360
92
96
100
90
150
Of the first, being a. gross exaggeration, and indeed
impossible, nothing more need be said ; and the
last I think is not very probable. Dr. Hooker may
have been deceived in estimating the height, concealed,
as the greater part of the je t almost always is.
by the volumes of steam that are carried up with it.
By taking a mean of the remaining three, we have
92|-, or, if our estimate of 80 feet be taken into
the account, rve have 86^ for the average height,
which may perhaps be about the truth. The fact
however of Mr. Baine, who accompanied Sir John
Stanley, having ascertained geometrically, and Avith
great care by means of a quadrant, the greatest
height to have been 96 feet, AA'ould seem to put
conjecture out of the question. I make use of the
strong term “ impossible” as to the estimate of
Olafsen and Povelsen, advisedly; for, although I
am not aware of any theory in hydrodynamics by
Avhich the limit of such a je t may be assigned, yet
I understand it has been pretty Avell ascertained,
by direct experiment, that no momentum gÍA'en to
a column of water, issuing from a pipe, Avill throAv a
perpendicular jet to the height of ninety f e e t : that
at Versailles, the Grandes Eaux play only to the
height of eighty fe e t; and that, by an experiment
made of applying a double force, they could not
succeed in raising the column to ninety feet.
Three things Avould seem to operate against an
ascending column of Avater— the increased resistance
of the air from its increased velocity or momentum
;—the separation of the column into spray
as it ascends ;— and the gravity of the column itself,
each stratum of Avater pressing on that beloAV it.
But if practice has established the fact that ninety
feet is to be considered as the m aximum, Avhat are we
to say to the jets of the Ncav Geyser, the greatest elevation
of Avhich, as stated to have been observed by
Sir John Stanley, amounted to 132 feet?— only this,
that as it Avas not ascertained, like that of the Great
Geyser, by the quadrant, the small diameter of the
jet, and its extreme rapidity dividing the column
toAvards the upper part into threads, may have led
to an inaccurate estimate. But Sir John Stanley has
himself solved the question. H e says, speaking of
the Geysers, “ Nature noAvhere offers objects bearing
a resemblance to them; and art, even in constructing
the Avaterworks of Versailles, has produced
nothing that can at all illustrate the magnificent
appearance of the Geyser.” It is most true, as
K 3