E A R 
«.iG 
mg any thing of Dr. Stukcley’s difcoveries. But this 
learned Italian imagined the eledtric matter which occa- 
fions earthquakes to be lodged deep in the bowels of the 
earth, agreeably to his hypothefis concerning lightning. 
Dr. Prieftley alfo, in his Hiftory of Electricity, contends 
for the agency of the electrical fluid in the production of 
earthquakes; and, from the doctrines previoully advanced 
by Stukeley and Beccaria, he frames a third hypothefis 
of his own. 
All thefe, it is true, agree in the main ; but, if a par¬ 
ticular folution of the phenomena is required, perhaps 
every one of them will be found deficient. Later theo- 
rifts have therefore attributed earthquakes to the fudden 
explofion of inflammable fubftances in the bowels of the 
earth, verified upon the principles of modern chemiftry, 
and which feed volcanoes ; or from the hidden formation 
of elaftic gas, by the burfling of the waters of the ocean 
into the fiery chambersof volcanoes. Dr. Mitchell, pro- 
feffqr of chemiftry in Columbia college, New York, has 
lately written a very ingenious Effay on this fubjeCt, and 
adduced many fatisfadlory proofs that the earth is ex¬ 
tremely cavernous under the fea, and that fubterranean 
communications exift between the mod diftant craters : 
a faff which feems mod clearly evinced by the effects of 
the earthquake above defcribed in 1755, which deftroyed 
Lifbon, and which, from the point of its central explo¬ 
fion, pa'lfed under the fea, and found vent even at the 
narrow mouths of fprings in very diftant countries and 
iflands, and even in another continent, and as far as the 
American ifies. 
The theory juft ofFered by Mr. Blanchet, of the Ame¬ 
rican philofophical fociety, afcribes the explofion of vol¬ 
canos and earthquakes to the expanfion of atmofpherical 
air; upon the fame principle that (olid bodies are burft 
by the fro ft, or that trees are fliivered by lightning. The 
mod Ample principles of natural knowledge, ((ays this 
writer,) teach 11s that atmofpheric air cannot pafs from 
its permanently aeriform ftate to that of fluid or (olid, 
by any degree of cold with which we are acquainted. 
Admitting this to be true, there is no longer any ground 
of furprife in feeing the burfting of bodies which refill: 
the force of freezing water. The air, a fluid of perma¬ 
nent elafticity, being compreffed, and forced to give way 
to the particles of water, which cold, or the attractive 
power of the atoms of bodies, draws violently together* 
it follows that the ice, into which the water is converted, 
miid break afunder, in order to afford a paffage to this 
aeriform fubltance, which cold can neither condenfe nor 
make folid, and mud rend and (hiver, with a cracking 
noife, the veffels no longer able to hold it. 
“ No perfon feems yet to have accounted for the (hat. 
fering of trees by the ftroke of lightning. A moment’s 
reflection, however, fuffices to difcover and explain the 
caufe. As it is only by a careful analyfis of fadts that 
we carl deduce juft conclufions, I proceed to examine 
what happens in the moment of the lightning ftriking a 
tree, and it will be feen whether this ladder will enable 
us to reach the caufe of this phenomenon. Repeated 
experiments have demonftrated that caloric, or the matter 
of heat,, is the cati(e of the repulfive power ol the atoms 
of bodies ; and there is no doubt that the more the atoms 
of a body are removed from one another, the greater is 
the capacity of fuch a body to contain caloric. It is alfo 
inconteftably proved, that the bodies which are conftantly 
in the ftate of gas, in the common temperature of the 
atvnofphere, contain a great quantity of caloric, and in 
proportion to their fpecific capacity for holding it. So 
likewife the eleCtric fluid, or what might with more pro¬ 
priety be called the eledtric gas, muft contain a prodigious 
quantity of caloric, fince this element always exifts in the 
ftate of gas, and the more this gas is accumulated, the 
more the amount of fpecific heat muft alfo be augmented. 
This being premifed, w'henever the lightning (which is 
only an accumulation of eleitric gas, difeharged from one 
cloud to pafs to another containing a lefs quantity) hap¬ 
pens, in its courfe, to ftrike a tree, the tree becomes lb 
EAR 
fuddenly overcharged with caloric, that the air and other 
conftituent parts of it, which are difpofed rapidly to com¬ 
bine with heat, undergo expanfon , and thereby (hiver the 
tree, in order to force a paffage, and to fet themfelves at 
liberty. I cannot compare this phenomenon to any thing 
better than to the difeharge of a cannon or of a mulket; 
for every body knows that the difeharge of a cannon is 
owing to the ludden expanfion of the conftituent parts of 
the powder by the introduction of caloric. The fame 
principle is found to be the immediate caufe of the erup¬ 
tion of volcanoes, and of earthquakes. 
“ Whatever may be the agent which kindles and in¬ 
flames volcanic fubftances, whether it be the eledtric gas 
which communicates its fire to thofe mod: inflammable 
fubftances, fuch as fulphur, nitre, &c. or whether it be 
the fubterranean heat, which, in making its efcape, fets 
fire to thofe fubftances, dill it is certain that atmofpheric 
air muft be found in great quantities in the interior of 
volcanoes. For, fince the ever-memorable difcoveries of 
Lavoifier, of Fourcroy, of Scheele, and of Ingenhouz, 
on combuftion, it is admitted as a demonftrable truth, 
that the burning of combuftible fubftances is owing to 
oxygen; that is to fay, it is fixed and abforbed by the 
body in combuftion, while the caloric and the light, 
which are combined with it, efcape, in order to form the 
flame, the light, and the heat. In this manner atmo¬ 
fpheric air is one of the effential agents in fupporting 
the fire of a volcano. Thefe things being premifed, as 
foon as a volcano is kindled and fet on fire, the atmo¬ 
fpheric air which feeds it, as well as the bafes of lul- 
pliur, of water, &c. which are alfo converted to the ftate 
of gafes by the evolution or accumulation of heat, are 
expanded, and break out with a violence and impetuo- 
fity not to be reftrained by the force of oppofing bodies, 
and thereby give birth to.earthquakes, &c. This theory 
is remarkably countenanced by the common and uniform 
feries of occurrences which follows the eruption of a 
volcano. In the firft place, as foon as it is kindled, there 
appears a thick fmoke ; foon after, when the air, &c. be¬ 
come expanded, ftones of enormous bulk are thrown out 
to great diftances into the aerial regions, accompanied 
with earthquake, and agitation of all the furrounding 
country. As foon as the fuperfluous air is difeharged 
and fet free, there fucceeds a bright flame, which feems 
to reftore ferenity to the abyfs, which again, after H fhort 
time, vomits forth a (hower of fiery and definitive mat¬ 
ters. In fhort, all thefe explofions are produced by the 
fudden extrication of fome matter incapable of confine¬ 
ment, or to the expanfion of air in a refilling body.” 
EAR'THY, adj. Confiding of earth.—All water, efpe- 
cially that of rain, is fiored with matter, light in compa- 
rifon of the common earthy matter. Woodward. 
Long may’ft: thou live in Richard’s feat to fit, 
And foon lie Richard in an earthy pit! Shahefpearc. 
Compofed or partaking of earth ; terrene : 
To furvey his dead and earthly image, 
What were it but to make my forrovv greater? Shakfp. 
Inhabiting the earth : terreftrial: 
Thofe earthy fpirits black and envious are; 
I’ll call up other gods of form more fair. Drydeti. 
Relating to earth : 
Mine is the fhipwreck, in a watry fign; 
And in an earthy, the dark dungeon thine. Drydeti. 
Not mental; grofs ; not refined : 
Teach me, dear creature, how to think and fpeak ; 
Lay open to my earthy grofs conceit, 
Smother’d in errors, teeble, (hallow, weak. 
The folded meaning of your words deceit. Shakejpcare , 
EAR'THY Triplicity, in aftrology, the figns Tau¬ 
rus, Virgo, and Capricorn. 
EAR.'VVIG, f. [eape and pijja, Sax. a grub.] An 
infett, imagined to creep into die ear. See Fqrfscula, 
—Earwdgi 
