227 
hay, or straw ; but he has left out the element of decay. The 
laboratory that I mentioned was the accumulated decayed 
vegetation which would naturally belong to an undisturbed 
forest. 
Since I made that suggestion in Nature I have again visited 
the cave, and not satisfied this time with seeing its interior, I 
obtained permission to examine the summit of the cavern. It 
is now a gentleman’s private grounds. The gardener pointed 
out to me certain spots where could be distinctly heard the 
workman’s hammer when he struck the top ; the thickness was 
not great. But what I want to direct attention to is this, that 
instead of the decayed vegetation that appertains to an unfre- 
quented forest, it is now a gentleman’s lawn, from which the 
gardener’s broom removes every seared leaf. The conditions are 
altered ; the laboratory is removed, less of the limestone is dis- 
solved, and as a consequence the formation of stalagmite must 
be slower. 
In the report read before the British Association at Exeter* 
Mr. Pengelly says, that “ it may not be out of place to state 
here as a fact of at least large generality, and to which there is 
no known exception, that in those branches of the cavern where 
the drip is at present very copious the stalagmitic floor is of 
great thickness, and where the drip is but little there is no 
floor, or an extremely thin one ; that, in short, the present 
amount of drip in any locality affords a good index of the 
thickness of the floor there.” 
Is it probable that for 7,750 years there has been a uniformity 
of drip in any one spot, seeing that any accidental accumulation 
of vegetable matter that retained the surface water at one time 
more than at another, would alter that drip ; and without uni- 
formity of drip it is shown by the above quotation that there 
would not be uniformity of accretion. 
The non-uniformity of stalagmitic accretion is observable in 
Poole’s Cavern ; for this boss, taken from the gaspipe, commenced 
forming at the rate of an inch in four years ; but it did not 
long continue to form at that rate, for the present measurement 
of the boss proves that it fell to a formation of an inch in 16£ 
years. 
Now uniformity of accretion is necessary to the correct action 
of Mr. Pengelly’s chronometer. 
It is no venture to say that neither in this nor any other 
country has any cave had more careful and scientific exploration 
than has this of Kent’s Cavern; and no explorer could be more 
explicit than Mr. Pengelly in telling us all the facts of the case. 
* British Association , 1869, pp. 16, 17. 
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VOL. XIII. 
