254 EVOLUTION OF SULPHURETTED HYDROGEN. 
ART. LIV. — ON THE SPONTANEOUS EVOLUTION OF SUL- 
PHURETTED HYDROGEN IN THE WATERS OFTHE WES- 
TERN COAST OF AFRICA AND ELSEWHERE. 
In the course of a lecture on this subject, delivered at the 
Royal Institution, by Professor Daniell, he observed, that it 
was curious that the impregnation of the waters of Western 
Africa with this deleterious gas had so long escaped attention. 
In water seaward forty miles its presence can be detected; and 
it exists in considerable quantity in the Volta, in Lopez Bay, 
in the Grand Bonny, &c. ; it spreads over an area of 40,000 
square miles, from about 8° north to 8° south latitude. The 
origin of this vast accumulation of sulphuretted hydrogen, 
Mr. Daniell attributes, not to volcanic action, not to the de- 
composition of pyrites, nor to the process of the decay of ani- 
mal matter, but to the action and reaction of the vegetable 
matter carried down by the tropical rivers, and the sulphates 
always more or less present in sea-water. This, moreover, 
he has proved by experiment. Last winter he placed some 
fallen leaves in a jar of new river-water ; also a similar pro- 
portion in a second jar, with three ounces of salt, and in a 
third, with a like quantity of the sulphate of soda — all closely 
stopped, and a card-board, with acetate of lead, over each. 
After having been kept three months in a warm closet he ex- 
amined them. The first emitted the common smell of decay- 
ed leaves ; the second that of a pleasant conserve ; but the 
third, no words could convey the stinking odor, nauseous be- 
yond all description. This of itself was sufficient to establish 
the generation of sulphuretted hydrogen ; but further, the 
usual blackening of the lead of the card-board in this jar only, 
left no doubt on the matter. Whenever, then, sea-water 
holding sulphates in solution mixes with fresh water and veg- 
etable matter, this gas must be produced, and its effects on 
animal life are well known. It is a record in Italy, as well 
