188 Description of « Lake of Sulphurie Acid. 
phate of lime: when the evaporation was pushed further, 
the same liquor furnished crystals of alum. 
5. The crystals of alum when separated, and the liquor 
when concentrated still further, gave simple sulphate of 
alumine. 
6. When, by successive crystallizations, the sulphate of 
lime and alum were. separated, the remaining liquor, or 
mother-water, decomposed by the ammonia, formed a pre- 
cipitate which was composed of iron and alumine. 
7. The liquor thus decomposed by ammonia, when eva- 
porated, and the residue calcined, gave me but very little 
sulphate of potash, without any thing else. f 
8. These experiments prove that the acid liquor in ques- 
tion is composed of, 
1. Sulphuric acid. 
2. Muriatic acid. 
3. Sulphurous acid. 
4. Simple sulphate of alumine. 
5. A small quantity of common alum. 
6. Sulphate of lime. 
7- Sulphate of iron. 
8. Some particles of sulphur. 
The sulphuric acid is more abundant than the other sub- 
stances : next comes the muriatic acid: the simple sulphate 
of alumine, the sulphate of iron, and the other substances, 
are but in very small proportions. 
Description of the Plates. 
Plate I. Sketch of the country in the yicinity of the 
volcano. 
A. Place where the river disappears. 
B. Mouth of the volcano. 
Plate II. Interior view of the Solfaterra. 
1. Lake of sulphuric acid. 
2. Section by which the water is discharged which forms 
the river Songi Pahete. 
3. Part of the volcano where the volcanic vents are. 
4. Old volcanic vents now extinguished. 
5. 5. Volcanic apertures vomiting smoke and fused sub-- 
stances, 
6. Place at which I descended into the volcano. 
7- The only place where water can be drawn from the 
lake. 
*,* In our last Number correct the following errata, occasioned by ty- 
pographical mistakes in the or1GINAL: page 130, line 28, read Sombrarou ; 
and in p: 130, 1, 41, p.131, 1, 18, 1, 22, and |. 25, read Sungi Pahete. 
XXXII, ln- 
