4. The Boiling Springs of Savu-savu.—These springs figure in all the descriptions of the group, and they are also famous amongst the natives. Since they were described by Wilkes, who visited them in 1840, in his narrative of the United States Exploring Expedition, many accounts of them have been written by subsequent visitors; not infrequently they have been sketched as well as described; and several analyses of their waters have been made.[[21]] The accounts of these springs that lie before me extend at intervals over a period of nearly sixty years; but I shall allude to them only so far as they throw light on the history of the springs during this period.
The principal springs are situated in a slight hollow in a more or less level tract extending in from the beach, and are distant about 150 yards from the shore and about ten feet above the sea-level. They are five or six in number, and at the time of my visits in July and November, 1898, they were boiling briskly, the thermometer readings being 208-210° F., but the mercury probably fell two or three degrees in withdrawing the thermometer. When, as was the case when Wilkes visited this locality in 1840, there is but a slight appearance of boiling, brisk ebullition is produced by covering them over with leaves. The natives call this locality Na Kama, which signifies “the burning place,” and employed the springs extensively for cooking their food. Just as Wilkes describes, a freshwater brook runs past the springs and receives their outflow. The temperature of the brook immediately above the springs is that of an ordinary freshwater stream 75-76° F.; but below it is scalding. The account given by Wilkes of the spring and of the brook in 1840 applies to them in our own time. The small stones lying in the effluent channels of the springs are incrusted with siliceous sinter, and a green alga lines the sides, bathed generally in the steam but sometimes partially immersed in water only a few degrees below the boiling point. It is noteworthy that this alga which was flourishing in July was all dead in November.
The scalding water also oozes through the sand of the adjacent beach in abundance for a distance of at least some hundreds of yards. It is even stated that as far as Ndaku, a mile to the westward, the hot springs issue at intervals through the beach.[[22]] There are evidently also extensive submarine springs close to the beach; and probably Wilkes was not far from the truth when he remarked that the “whole area of half-a-mile square seems to be covered with hot springs.”
Off the beach, a few hundred yards to the westward of the springs, is a batch of dead reef formed of massive corals and only approachable from the shore at extreme low-tide when it is a little exposed. From numerous small holes and cracks in the dead-coral hot water issues almost at the boiling point (210° F). It is apparent that these springs have appeared at this particular spot since the corals grew. But it is remarkable that this has been apparently going on since the visit of Wilkes in 1840. He refers to a coral rock, distant one-third of a mile from the springs and 150 feet from the beach, through which boiling water was issuing in several places. This rock which was then 10 feet wide and 20 feet long, was at his visit exposed for three feet at low-tide and covered at high-tide.[[23]]
The geological characters of this locality are described on page [191]. I may here remark that if these thermal springs occupy the position of an old crater, it would require much imaginative power to restore it now. The off-lying small island of Nawi might by its situation appear to countenance this idea, but I found no special indication, when I examined it, in support of this view. From the geological character of the district, I would infer that if a crater once existed here it was submarine and that it has been long since obliterated by marine and aërial denudation. The boiling springs come up through apparently a rotten volcanic agglomerate. The slight hollow of three or four feet deep, in which they lie, was considered by Kleinschmidt to be an old crater cavity; but it is only 40 or 50 feet across, and in the earlier descriptions the hollow is described as surrounded by a mound of earth. As shown below, the natives themselves may be held responsible for many changes in the surface around the springs. There is, in fact, no trace of a crateral cavity in this district now.
I will now briefly notice the history of the boiling springs since 1840, when they were visited by Commodore Wilkes. At that time there were five springs, situated in a basin 40 feet across, and possessing a temperature of 200-210° F. Although there was scarcely any appearance of boiling, rapid ebullition could be excited by covering the springs with leaves and grass. The natives alleged that the springs had always been in the same condition. In 1863, when the Chief of Wainunu (Tui Wainunu) came to fight the Savu-savu people, he endeavoured but without success to choke up the springs by heaping earth over them. I was informed of this circumstance by Mr. A. H. Barrack, the owner of the springs. Miss Gordon Cumming also refers to it in her book At Home in Fiji. When this lady visited the springs in August, 1876, they were intermittent in their action, the highest making a fountain two to three feet high. According to the description of Kleinschmidt they were in the same intermittent condition in May of the same year. There were then four springs situated in a bowl-shaped hollow. The two larger springs were not constantly bubbling up, but displayed periodic ebullitions of about twenty minutes’ duration, the waters disappearing in the intervals. The other two springs were not then active. Horne, who visited this locality in 1878, refers to three or four principal springs situated in the centre of a hollow, which was surrounded by a mound of earth, the water boiling up to the height of about a foot.
About this time the springs entered for a while into a new phase of action and assumed the form of geysers. According to information received from Mr. A. H. Barrack and other old residents in Savu-savu, the waters spouted up to a height of from 40 to 60 feet, not vertically but at an angle. Each outburst, which lasted for ten or twenty minutes, was followed by a similar interval of repose, during which the springs dried up. This continued for a month or two, after which the springs gradually resumed their normal level. When I visited the springs in July and November, 1898, they were boiling briskly, attaining a height of a few inches, and showed no signs of intermittent action.
I come now to the different analyses that have been made of the water of these thermal springs of Savu-savu. Specimens have been analysed at different times by chemists in various parts of the world, in America, in Germany, in Australia, etc., and the results as far as known to me are now appended.
A. Analysis by Dr. C. T. Jackson of Boston, U.S., of the water
obtained in 1840 by the Wilkes Exploring Expedition.[[24]]