8 Prof. Daniel 1 on Sulphuretted Hydrogen 



4. Water from off Grand Bonny, about three miles inside 

 the mouth of the river. 



One pint yielded 208 grains of the same salts as above, and 

 Sulphuretted hydrogen, 3\500cub. in. (28'Ocub. in. per gall.) 



These results appear to have attracted no particular atten- 

 tion at the time when they were obtained. The old hypothesis 

 of the corruption of the specimens probably sufficed for their 

 explanation upon this as upon other occasions. 



Thus there can be no doubt of the important fact of the im- 

 pregnation of the waters, upon the western coast of Africa, 

 with sulphuretted hydrogen, to an amount, in some places, 

 exceeding that of some of the most celebrated sulphur springs 

 in the world; and of the injurious effect of such impregnation 

 upon the copper sheathing of ships, you will be convinced by 

 the experiments upon the table. 



Were any further evidence wanting, it would be found in 

 the state of the copper of the Bonetta, which lately returned 

 from the coast of Africa, and three sheets of which were sent 

 to me from the Admiralty for examination. 



Nos. 1 and 2 were pretty uniformly covered on the outside 

 with a green crust ; and on the inside, as evenly, with a black 

 crust of equal thickness. They were very thin in parts, and 

 here and there eaten into holes. 



No. 3 was in a much worse state, very thin, and eaten into 

 large holes. In most parts it was easily broken by the fingers ; 

 one of the holes, of an irregular shape, measured eighteen inches 

 in length by four inches and a half in width. This sheet was 

 covered with green crust chiefly, on both sides; but there were 

 evident traces of the black crust on the inner side. 



Upon analysis the black crust was found to consist of sul- 

 phuret of copper, and the green of oxy-chloride of copper. 



There can be no doubt that the injury to the copper arose, 

 primarily, from the sulphuretted hydrogen. The gas appears 

 to have penetrated to the inner side of the copper, where in 

 Nos. J and 2 it has been protected from the further action of 

 the sea water; by which, on the outside, the sulphuret was 

 converted into chloride of copper. This conversion appears 

 to have taken place on both sides in No. 3, from the sea water 

 having penetrated to the under side in consequence of its greater 

 corrosion. 



That the establishment of this fact is of some importance in 

 a mercantile point of view, I think I shall be able to convince 

 you by two anecdotes which I will now narrate. 



Not many years ago a new copper company set up a smelt- 

 ing establishment and brought their copper to market : some 

 merchants purchased sheathing of them, coppered their ship, 



