[317] 
According to this account the Elm mentioned Obf. 7th 
may be a proper.fimiHtudCi but I have informations from one in 
Town that was fifhing in thcChar '^el^that whilft his boat trembled 
under him, and the lefTer fillies f^med much affrighted by an un- 
ufual skipping, he heard the mnrmur as of a rifingv;ind, which he 
fancied juft then breaking out, and rupbling upwards, but felc 
none. The like relation, as to rumbling h\ the air, \ have from good 
hands concerning feme people that were ih Donrton park in Buckz 
ingham (hire^ which I mention only for the.diflance fake, for moll: 
hereabouts agree in the fame fancy, though at firft fome thought 
the rumtling might proceed from a Cart, but they could nordif- 
cern which way it went; Imy felf perceived it like diftant thun- 
der, a noife determined to one place, not fleeting or pafTing from 
me, tho the crafh which ended the (haking of the building a little 
deceived me in my firfl imaginations. 
Upon all which accounts its feems to me that the mode of its tre> 
mulous and vibrating motion, together with its found, may be 
befi: explained by thofe efFervefcences mentioned in theyth Obfer. 
and I believe you may have a great many more inftances from 
y out chemical cperationsi particularly in drawing off the fpirit of 
Nifrey with which Lewiyy will allow the third part only of^ retort 
£obe filled for fear it fhouid" break afunder. 
But to ftick to the moft common inftance of water feething in a 
covered vefTel, we find the Anciems dcfcribed a fort of earthi]Hakss 
by this very analogy ; and Arifiotle in his book de Mmdo^ where 
he gives them feven appellations according to fome accidental af- 
fedions, whereby they may be dif}:iguifhed, calls thofe of this kind 
by the name of BpccAja/ as if theyboyled, becaufe they ply up and 
down : I know that fome may interpret fuch a one to be apulfe» 
but when I faid that ours was none, I diftiuguifhed it from the 
other, according to .the common way, by a different mode in their 
motion as they affedl the fenfe, which now to explain more fully, 
I take this that happened here to be no fuch forcible, or irregular 
ehullition raifing the earth with intermitting (hocks, as that of 
Mechlin for inftance Afrit 4. Anno 1640. defcribed by VmlieU 
mont^ hxsx a regular effervefcence of inclofed vapours more evenly 
difperfed, working up and down the earth with a trembling of 
each part, and a reciprocal agaitation of the whole, for fo it was 
perceived. 
1 1 This explication feems to be the more probable, becaufe I 
could never yet meet with any> who pretended to determine from 
what part this #m%//^?fe came orv/hether it went, and if any one 
had 
