205 
E A E T IT. 
recollect that Herculaneum, the date of whole debruc- 
tion is well known, is covered by nearly feventy feet 
of lava, intcrl'peifed with feven didindt feams of fri¬ 
able earth, the whole covered with good 1 'oil. Yet all 
this has been the undoubted produce of lefs than 1800 
years!” 
It appears to Mr: Howard, that M. de SaufTure, in con¬ 
ceding the infinitely removed origin of what he terms 
the carcafs of .the globe, has not adverted to the hetero¬ 
geneous-afiemblages which much have been produced by 
the deluge; and which, to a mind acquainted with the 
celerity of chemical precedes, muft prove tIre poflibility 
of every alteration attebed by natural phenomena having 
happened within the period alligned by the facred writers. 
That the omnipotent Creator nuib, according to this au¬ 
thor’s hypothelis, have produced the vifibLe material 
univerfe by means of the fame general law's, which are 
now' employed to preferve it, is a mere petitio principii ; 
the affirmative is incapable of proof, and if it were aemon- 
brated, leads to no important conclufion. The Molaic 
account of the creation implies a diJlinEl revelation. Mr. 
Howard mud have forgotten that authentic tradition 
could not extend to events antecedent to the exidence of 
mankind. We may jnftly conclude, that -men are too 
fhort-fighted to claim wifdom as an argument a priori, to 
ebablilh what are to be the laws of nature, and what have 
been the events that have happened in the world : the 
only thing that our uiifdorn can. pretend to reach, is to 
judge, what are thofe laws, and what mud have .been the 
a£ling cdufes to have produced certain ejfeEls. —See the 
works above alluded to; and Monthly Review, New 
Series, vol. 2, 3, 5, 6, 15, 24, 25. 
The merits of the Huttonian Theory of the Earth 
have in part been recently debated between Sir James 
Hall, Bart, and the ingenious Mr. Kirwan. In the third 
and fifth volumes of the Edinburgh-Tranfadtions, Sir 
James Hall attempted, by feveral experiments, to inva¬ 
lidate fome of the podtions laid down by Mr. Kirwan, in 
his explanation of this Theory. In reply to thefe,, Mr. 
Kirwan has publilhed a paper in the eighth volume of 
Tranfaftions of the Royal Iridi Academy for 1802, with 
the view of examining the force of the reafoning em¬ 
ployed by fir James, as well as of determining the confe- 
quences fairly deducible from his experiments. Some 
difficulties had been darted againd the, opinion that gra¬ 
nite was ever in a date of fufion, from the feltfpar con¬ 
tained in it being, though the mod fufible of the two 
fubdances, found in this done with its crydals rqgularly 
defined, while t(ie quartz formed a confuted and irregu¬ 
lar mafs, moulded on the crydals of feltfpar; and dr 
James replied to them By arguments which Mr. Kirwan 
here eudeavours to refute. As the principal circum- 
dances, however, on which dr James reds his opinions 
refpedting the (ubjedt of granite, depend on fome expe¬ 
riments on whin, we fhall explain them. Whin, it may 
be obferved, comprehends in Scotland, grundein, bafalt, 
trap, wacken, and porphyry ; dones in which (except the 
lad) none of the component ingredients are found regu¬ 
larly crydallized. Grundein, a compound of feltfpar and 
hornblende, intimately mixed with eaclwnher, but im¬ 
perfectly and confufed-1 y crydallized in minute grains, was 
the fubjedt of t-he experiments here related. “ This fub- 
dance, (lays Mr. Kirwan,) dr James vitrided by adrong 
heat and fubfequent rapid cooling. A fragment of the glafs 
thus produced being introduced under a narrow muffle 
and heated to 21 0 , in one minute became fo foft as to yield 
readily to the preflure of an iron rod, but after a fecond 
minute it became quite hard, though the temperature 
had been dationary ; the fubdance thus hardened under¬ 
went a thorough change, it lod its vitreous character, 
its fradture was like that of porcelain, and it was fufible 
only in a heat of 31 0 . In another experiment he found 
this change to take place even before the glafs was in 
perted fufion ; -for while both ends of a fragment of this 
glafs were fupported on reds of clay, it was found not to 
' Vol. VI, No. 343. 
fink down between them until the heat was raifed to 30°. 
In another experiment he found the confolidati n which 
lie calls crydallization, to take place even while the heat 
was gradually increafed, and the fubllance dill fo vifeid 
as to retain the original fhape of the fragments. In ano¬ 
ther experiment, where the glafs was (lowly cooled, its 
texture was found completely to referable that of whin- 
done, the failure was rough, forty, and cryfalline, with 
a number of Ihining facettes interfperfed through the 
mafs, and a few crydals in the cavities produced by air- 
bubbles.” 
In order to (hew that thefe experiments are deceitful 
in the conclufions to which they lead, Mr. Kirwan com¬ 
pares the diferiminating characters of natural whin with, 
thofe of the artificial : “ 1. The natural tVhins, particu¬ 
larly amygdaloids (vulgarly called toadj'bnes) , frequently 
contain calcareous fpar and zeolyte , now as the former 
contains fixed air, and the latter a large proportion of 
water, I hardly think fir James, who profede^ not t-, agree 
with Dr. Hutton in all points, will allow thefe to have 
been .vitrified or fufed. 2. The natural whins, according 
to Dr. Kennedy’s datement, lofe five per cent, of water 
and other volatile matter when heated to rednefs.. It is 
not (aid whether the artificial lofe any part of their weight 
by fuch treatment, but it is plain they would not, (ince 
even the lavas of Catania and Piedmont, though of an¬ 
cient date, lod none, as Dr. Kennedy exprefsly notices, 
and have thus afforded an excellent criterion for diitin- 
guilhing the long conteded origination of thefe fubdances. 
3. As fir James has neglected giving a complete account of 
the external characters of the natural whins, which were 
the fubjedt of his experiments, as alfo of regenerated or 
artificial whins derived from them, and as I have not my- 
felf feen them, it is difficult for me to compare them 7 with, 
each other, and would indeed be impodible if fome ac¬ 
count of them had not been given by Mr. Pidtet in his 
valuable Journal Britannique, copied into the 5th vol. 
of the New Rozier’s Journal, p.313. It is the refult of 
the examination botii of the natural and artificial.whins 
by tire Society of Natural Hi dory at Geneva. 
“ As to the natural grundein, they remark that it be¬ 
trays not the lead mark of an igneous origin, but that 
the whins which dr James produced from it had every 
didinflive character of a lava, and even of a porous lava. 
The bafalt (or rather frapp) on which the'cable of Edin¬ 
burgh bands, is of a compadt druid lire ; the artidcial 
produced from it, (Ir James tells us, fo greatly refernbles 
it both in colour and texture that it would be difficult 
or perhaps impodible to didinguifh them, but for a few 
minute air-b~abbles, cliflingui/hable in thetartifcial. Neptunids 
will, however, confider this as a leading character of dif- 
tin/ftion. The mineralogids of Geneva add, that the 
colour of the artidcial is deeper, and its hardnefs greater, 
than that of the natural. If the fpecific gravity and 
other characters of both were given, it is probable that 
other differences might be perceived. It is only in thefe 
characters that any difference can be expeCted, as the in¬ 
ternal compofitiort muff be the fame in both. 
“ Of the remaining artificial whins I can .give no ac¬ 
count, their external characters having been omitted ; 
I cannot, however, pafs over the general inferences that 
(ir James deduces from his experiments, namely, ‘that 
the arguments againd the fubterraneous fufion of whin- 
done, derived from its bony character, feem now to be 
fully refuted for, net to repeat what has been already 
dud, that many of them contain fubdances whofe exi(t- 
ence is incompatible with that hypothefis, I mud farther 
add, that tire upright date in "which many of them exib, 
for indance, the bafaitic pillars of .Staffa, and of the 
Giants Caufeway, and of many other countries, the bads 
they red on, fometimes granite, fometimes gneis, fome- 
times coal or lime-done, and the total abfence of all dgns 
of the operation of fire, forbid us to entertain any doubt 
of their production in the moid way. Nay, the college 
of Dublin now poffefles fragments of bafaitic pillars in 
3 G which 
