28 On Tropical Miasmata. 
“To each bottle of an acidulous water, bottled in the year 
1828, I added from six to cight grains of sugar, and preserved 
them properly corked and sealed in a cellar. After about 
three months, I opened some of the bottles; the water was 
found to smell very strongly of sulphuretted hydrogen. After 
about thirteen months, a few bottles were opened again, and 
the water smelled also very strongly of sulphuretted hydro- 
gen. ‘ In the bottles a black sediment was found, which I sup- 
posed to be a sulphuret of iron. Three years and a half after, 
many of these bottles were opened, and that black sediment 
collected. According to my analysis, it consisted of iron and 
sulphur very nearly in the same proportion as in iron pyrites. 
There was no doubt but the crigin of this sulphuret of iron 
must be derived from the reaction of the sugar upon the sul- 
phate of soda contained in the mineral water, whereby a sul- 
phuret of sodium was formed, which decomposed the carbonate 
of protoxide of iron contained in it, and thus produced a 
sulphuret of iron. Indeed, the water remaining after the se- 
paration of this sulphuret of iron, contained scarcely a trace 
of sulphate of soda, whilst the mineral water taken up from 
the spring contained, in 10,000 parts of water, 1.098 parts of 
this salt, without the smallest trace of sulphuretted hydrogen. 
“ Not only these experiments, but also other facts, favour 
the views of Professor Daniell concerning the origin of sul- 
phuretted hydrogen in the waters of the rivers on the western 
coast of Africa. It is well known that mineral waters con- 
taining sulphates,—for instance, that at Roisdorf near Bonn, 
—often acquire a smell of sulphuretted hydrogen, when any 
vegetable matter, as a small piece of straw, is accidentally 
present in the bottles. For this reason, in bottling, the great- 
est care is taken to remove such vegetable matter. 
“There is no question but that the sulphuret of copper 
found by Professor Daniell in the sheets taken from the bot- 
tom of the schooner Bonneta, has been formed in a similar 
manner as the sulphuret of iron above alluded to. A fur- 
ther proof of this opinion may be found in considering ano- 
ther observation, made public in the before-mcntioned Ger- 
man journal. 
“At the bottom of a basin enclosing a mineral spring, 
