we ee ole 
Reply of Dr. Daubeny to Prof. Bischof. 83 
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8th Objection.—If, according to Gay-Lussac, the hydrogen of 
the decomposed water goes to form muriatic acid with chlorine, 
the above mentioned acid ought to be general in volcanos. Now, 
it is wanting, according to Boussingault, in the voleanos under 
the equator in the New World, and according to Bischof, in those 
near the Rhine. 
Answer.—I believe, that muriatic acid will be found pretty 
constantly present in volcanos now in activity. Sir H. Davy 
found it at Vesuvius on both the occasions he visited that vol- 
cano, viz. 1815 and 1829. I myself in 1834, detected it there 
in great abundance; and in 1825, found it at the Solfatara, 
in the Island of Vuleano, and near Mount Etna. It has been 
discovered also in the volcanos of Iceland; in those of Java, 
at Mount Idienne; and of South America, at Purace. The 
sal-ammonia which so abounds in the volcanos of Tartary, 
shows, that it is also present there ; and the existence of it in 
the trachytic rock of the Puy de Sarcouy in Auvergne, proves, 
that it was a concomitant of volcanic action in days that have 
gone by. 
All therefore that Bischof is warranted in inferring from its 
absence in the case of the volcanos of the Rhine and Equatorial 
America, is, that it ceases to be disengaged when the action be- 
Comes languid or extinct. Now there are many ways of account- 
ing for this. In the first place, granting the acid to be derived 
from the sea-salt present in the water which originated the vol- 
Cahic action, it would cease to be generated when this fluid no 
longer obtained admission ; or, when the heat was inadequate to 
Cause the union of the alkali of the sea-salt with the earths 
Present ; and even if it were still generated, it might be pre- 
Vented from rising to the mouth of the crater, by combining in 
lis way with the calcareous rocks through which it had to pass. 
ence the carbonic acid, which Professor Bischof remarks as so 
abundantly evolved by the voleanos of the Rhine, may perhaps 
Tepresent an equal volume of muriatic acid, by whose agency it 
ad been evolved from the limestones that contained it. 
Thus have I replied seriatim to all the objections, which an 
‘cute and learned opponent has been able to adduce against the 
chemical theory of volcanos; and having done so, might be ex- 
Peete perhaps to proceed to some remarks on the one to which 
he himself has given the preference. 
