| Date collected. | Chlorine. | Sodium. | Calcium. | Calcium chloride. | Natrium chloride. | Total salts. | Density. | ||
|---|---|---|---|---|---|---|---|---|---|
| Dr. Jackson | 1840 | 3·57 | 1·66 | 0·36 | — | — | 7·20 | 1·009 | |
| Dr. Pieper | 1876 | 4·79 | — | 2·31 | 4·55 | 3·09 | 8·48 | — | |
| Mr. Rocholl | 1878 | — | — | — | 4·35 | 2·64 | 8·81 | — | |
| Prof. Liversidge | 1879 | (4·50) | (1·29) | (1·42) | 3·65 | 3·29 | 7·81 | 1·006 | |
| Sea-water, tropics | 19·46 | 11·08 | 0·46 | — | — | 35·00 | 1·02 | ||
| Date collected. | Chlorine. | Sodium. | Calcium. | |
|---|---|---|---|---|
| Dr. Jackson | 1840 | 3·57 | 1·66 | 0·36 |
| Dr. Pieper | 1876 | 4·79 | — | 2·31 |
| Mr. Rocholl | 1878 | — | — | — |
| Prof. Liversidge | 1879 | (4·50) | (1·29) | (1·42) |
| Sea-water, tropics | 19·46 | 11·08 | 0·46 | |
Comparison of the analyses of the water of the Savu-savu thermal
springs, stated in grains per thousand of water. continued
| Calcium chloride. | Natrium chloride. | Total salts. | Density. | |
|---|---|---|---|---|
| Dr. Jackson | — | — | 7·20 | 1·009 |
| Dr. Pieper | 4·55 | 3·09 | 8·48 | — |
| Mr. Rocholl | 4·35 | 2·64 | 8·81 | — |
| Prof. Liversidge | 3·65 | 3·29 | 7·81 | 1·006 |
| Sea-water, tropics | — | — | 35·00 | 1·02 |
It is to be inferred from the above that the quantity of salts in solution remains about the same, the proportion varying only in the four analyses, which extended over a period of forty years, between 7·2 and 8·8 grains per thousand grains of water. This is considerably less than the salts in solution in sea-water, namely 35 grains per thousand. The relative proportions of the salts, excepting those of calcium, do not vary more than we should expect in the case of analyses made by varying methods and probably with a varying degree of exactness.
Dana[[29]] considered from Dr. Jackson’s analysis that the water of the Savu-savu springs is probably of marine origin; but the absence of bromine and iodine, as especially remarked by Dr. Pieper and Prof. Liversidge does not support this view. We might also expect the proportion of the salts to each other to show a greater similarity to that in sea-water than they do. On the other hand the total volume of water discharged, not only by the springs proper but for several hundred yards along the beach, and also between the tide-marks and beyond, must be far greater than could be supplied by the rainfall of this portion of the Savu-savu peninsula, which is only one and a half to two miles across and 800 feet high. We must look, I think, for the source of these waters in deep subterranean streams or artesian basins that would be fed by the rains precipitated in the mountainous districts where the rainfall amounts to at least 200-300 inches in the year. This matter is further discussed in my general remarks on the hot-springs of this island (page [38]).
5. The Hot Springs near Ravuka.—These springs rise up in the centre of the breadth of the island about nine miles direct from the coast. They are about 200 feet above the sea and are situated on the Ndrawa branch of the Ndreketi River some two miles below the hamlet of Ravuka. They are on a small scale and ooze through a bed of rounded blocks and pebbles close to the water on the left bank. Their temperature in August, 1898, was 148° F. They are covered by the river when it is swollen by the rains, and very probably other hot-springs issue along the river-bottom. The conditions are not suitable for the formation of deposits.
6. The Hot Springs of Vuinasanga.—These thermal springs are also situated in the heart of the island on a tributary of the Ndreketi some three or four miles westward from Va Lili and about 150 feet above the sea. On each bank of the river four or five paces from the water and three or four feet above it, there is a small pool two to four feet wide. In June, 1899, the pool on the right bank had a temperature of 131° F., and that on the left bank of 134°. There were no deposits.
7. The Hot Springs on the South Side of the Nawavi Range.—These springs also lie within the borders of the valley of the Ndreketi. They may be “located” by describing them as lying a few miles inland from the north coast fronted by Mathuata Island. I did not visit them and have only learned of them from Mr. Thomson’s Mathuata paper.[[30]] That gentleman refers to them as two in number and situated at the back of the coast range about four miles inland from the village of Nangumu; but no particulars are given.