페이지 이미지
PDF
ePub

strongly of sulphuretted hydrogen. The sediment in the bottle only amounted to 0.5 graius of vegetable matter. Specific gravity to 1018.5. The results of the analysis, calculated for the imperial gallon. Sulphuretted hydrogen

6:18 cb. inches. Chlorine .

943-14 grains. Sulphuric Acid

82.70 Lime

19.14 Magnesia

27.68 Magnesium

32.71 Sodium . . . . 563.33

.....

1668.70

There was also a trace of potassa in this water.

The actual amount of dry salts obtained by evaporation, was 1696-0 grains. The difference between this, and the results of the analysis, is not more than usual in similar cases, and arises from the impossibility of determining the exact mode in which the several acids and bases are combined in the water, and from the difficulty of drying the salts without the decomposition of some of them.

2. “Water taken from river Volta, taken at twenty-eight miles from the mouth, (bearing north 67° 3' W,) by her Majesty's schooner Fair Rosamond, latitude 37° north, longitude 1° 10' east, on the 4th of September, 1839; season not rainy.” .

This water also smelt very strongly of sulphuretted hydrogen, the sediment in the bottle did not exceed 0.3 grains of vegetable matter. It contained per gallon Sulphuretted hydrogen

6.99 cb. inches.
Chlorine .

1411.68 grains.
Sulphuric Acid . . . 92.47
Lime

. . . . 14.75
Magnesia . . . . 35.70
Magnesium .

. •
.

.

. 12:46 Sodium

. . . . 916:20 Potassium

a trace

2483.26

Specific gravity 1025.4
Amount of Salts from evaporation 2480.0

3. “Water from the river Bonny, taken at anchor off the town in the river, by her Majesty's schooner, Fair Rosamond, on the 9th of October, 1839, about the conclusion of the rainy season.”

This water smelled slightly of sulphuretted hydrogen, and the sedi ment in the bottle weighed only 0•4 grains, and consisted of vegetable matter. The results of the analysis, were per gallon,

1.21 cb. inches.

Sulphuretted hydrogen ...
Chlorine
Sulphuric Acid
Lime
Magnesia
Magnesium
Sodium
Potassium

970-92 grains.

92. 10
17:36
33.65
47.11
553.06
a trace

1714.20

Amount of Salts from evaporation 1788

Specific gravity 1019.0 4. Water from the river Mooney, which empties itself in the northeast part of Corisco Bay, taken from about a mile inside the mouth, by her Majesty's brig Nautilus, September 4th, 1839. Rain had fallen, but the rainy season cannot be considered to have set in."

This water did not smell of sulphuretted hydrogen, nor did it afford any trace of that gas upon analysis; the total amount of sediment in the bottle did not exceed 0.1 grain. It contained per gallon, Chlorine .

1184:11 grains Sulphuric Acid

109 80 Lime . . . .

14:17 Magnesia ,

44.78 Magnesium

28.54 Sodium .

732:32 Potassium

a trace

2113.72

Amount of Salts from evaporation 2104

Specific gravity 1022.5 5. "Water from the river Gaboon, taken at four miles above Parrot and Konicky Island, by her Majesty's brig Nautilus, September 10th, 1839. Rain had fallen, but the rainy season was not considered to have set in. Latitude 0° 15' north, longitude 9° 33' east.”

This water afforded no traces of sulphuretted hydrogen. The sediment in the bottle weighed 0.2 grains. Chlorine

1130-75 grains Sulphuric Acid

120.08 Lime . .

23.05 Magnesia ,

43.58 Magnesium

35.41 Sodium

683.00 Potassium .

a trace

[blocks in formation]

6. “Water from Cape Lopez Bay, taken by her Majesty's brig Nautilus, September 28th, 1839, when the Cape bore W.b.Ń about ten miles. The rainy season had commenced.”

This water smelled very strongly of sulphuretted hydrogen. The sediment in the bottle weighed only 0.1 grain, and consisted of vegetable matter. It contained per gallon,

Sulphuretted hydrogen . 11.69 cb, Inches.
Chlorine

1467-37
Sulphuric Acid

115.20 Lime .

23:21 Magnesia . . . 41.02 Magnesium

28.44 Sodium

921-60 Potassium

a trace Lodine

a trace

[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]

2596,84

Amount of salts from evaporation 2576-00 .

Specific gravity 1026 7. “River Congo,—water taken off Shark's Point, at the entrance of the river, by ber Majesty's sloop, Wolverine, on the 11th of November, 1839, four days before the customary rains, but light rains having already taken place."

This water smelled very slightly of sulphuretted hydrogen. The sediment in the bottle weighed 0.4 grains, and consisted of vegetable matter. It contained per gallon,

Sulphuretted hydrogen , 0.67 cb. inches
Chlorine

106-11 grains
Sulphuric Acid

230 Sodium

70.00 And small quantities of other bases.

Amount of Salts from evaporation 188 grains

Specific gravity 1002-0 This is the only case in which the salts were discoloured by vegetable extractive matter.

8. “River Congo, water taken about thirty-five miles up that river, by her Majesty's sloop Wolverine, on the 11th of November, 1839, four days before the customary rains, but light rains having already taken place."

This water contained no sulphuretted hydrogen, and the sediment in the bottle was only 0.1 grain.

The amount of saline matter was only 8 grains, per gallon, and consisted of the Chlorides of Sodium, and Magnesium, and Sulphate of Soda chiefly.

Specific gravity 1000•3.

The most remarkable circumstance disclosed by the analysis of these waters, is the strong impregnation of the majority of them with sulphuretted hydrogen; which, in the case of the water from Lopez Bay, amounts to almost as much per gallon as in the Harrogate waters. The proportions of the saline contents do not differ materially from those which are usually found in sea water.

The extraordinary presence of this gas, would naturally lead at first to a suspicion that it might arise from some change which had taken place in the waters after they had been bottled, from the decomposition of some animal or vegetable substance, but this suspicion is inconsistent with two facts. 1st. That the waters became perfectly sweet a very few hours after the corks had been drawn. 20—That with the ex. ception of the very small quantity of sediment, mentioned in each analysis, the waters were perfectly free from any animal or vegetable substance, and the salts which they yielded upon evaporation, (with the exception of those from the Congo,) were snow white.

On the other hand, it is difficult to conceive how such a striking and important fact as the impregnation of the waters of the ocean, upon such a long line of coast, with this deleterious gas could so long have escaped observation. It is highly desirable, in many points of view, that its existence should be substantiated, and the limits of the phenomenon both along the coast and in the ocean, ascertained by further evidence. Its effects upon the copper-sheathing of ships cannot fail to be highly injurious, and a question of still higher interest even arises, whether this deleterious gas may not contribute to the well-known unhealthiness of the coasts, from which these waters are taken.

Upon searching for evidence of a similar phenomenon having been observed before, I have found in the Philosophical Transaction, for 1819, a memoir by the late Dr. Marcet, “on the specific gravity and temperature of sea-waters, in different parts of the ocean, and in particular seas, with some account of their saline contents." Out of sixteen specimens which he examined, he found one which was brought by Captain Hall, from the Yellow Sea, in the Chinese Ocean, which, from the account which he has given, must probably have been as highly charged with sulphuretted hydrogen, as those which I have just ex, amined from the coast of Africa ; and he observes, “ there is something in the developement of sulphur in sea-water, which is by no means well understood,” He also noticed, that a specimen brought by Mr. Schmidtmeyer, going to South America, from latitude 10° 50' north, longitude 24° 26' west, had an hepatic smell, and had blackened the bottle in which it was contained.

If the existence of this curious phenomenon should be confirmed, the origin of the sulphuretted hydrogen will probably be found to be the same, as that of the same gas in various saline lakes in different parts of the world, from which Trona or Natron is derived. The mud of the Lonar Lake in India, of a lake near Maracaybo, in South America, and of similar lakes on the north of Africa, are all found to be thus impregnated. The sulphuretted hydrogen thus adhering to the clay, has been supposed to be derived from volcanic sources, but Mr. Malcolm, son, in an able memoir lately printed in the Geological Transactions, says, that he has observed “the same phenomenon in the salt water inlets, along the Indian coast, wherever the bottom contained argillaceous and carbonaceous matter;" and he ascribes the effect to “ the decomposition of the sulphates in the water by the carbon, and the clay only prevents its passing off into the air, or mixing with the water by the power of adhesion."

The subject is full of interest, both in a practical and scientific point of view, and well worthy of further investigation.

I have the honor, &c.

J. F. DANIELL. To Sir John Barrow, Bart., fc.

King's College, 20th August, 1840. SIR.-In compliance with the directions contained in your letter to me of the 18tb inst., I have carefully examined three sheets of copper taken from the bottom of the « Bonetta," and transmitted to me by your orders, and have now the honor to report as follows:No. 1,-Labelled Bonetta, 1835; 6lbs. 2o2.—28 ounces.

2. " Bonetta, 1835; 6lbs. 402.—28 “

3. « Bonetta, 1835; 4lbs. 3oz.-28 “ All of the same dimensions, 4 feet long by 1 foot 2 inches wide.

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 incbes 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 sulphuret of copper, and the green of sub-chloride of copper.

Connecting these results with those previously obtained from the analysis of the waters on the coast of Africa, I have no doubt that the injury to the copper has arisen, primarily, from the sulphuretted hydrogen. The gas appears to have penetrated to the inner side of the copper, where in Nos. 1 and 2 it has been protected from the further action of the sea water; by which, on the outside, the sulphuret appears to have been 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.

I have the honor, &c.

J. F. DANIELL. To Sir John Barrow, Bart., fc.

King's College, Nov. 17th, 1840. SIR.-I have analyzed the two additional specimens of water from the Western Coast of Africa, which you did me the favour to send on the

ENLARGED SERIES.-NO. 1.-VOL. FOR 1841.

« 이전계속 »