Art. LIV.—Notes on the Thermal Springs, in the Hanmer Plains, Province of Nelson.
[Read before the Nelson Association for the Promotion of Science and Industry, May 4, 1870.]
Amongst the manifold blessings bountiful Nature has bestowed upon New Zealand, to which hitherto very little or no attention has been paid, none deserve our consideration more than the thermal sprin's situated towards the central parts of both islands.
Owing to the difficulty of access, and the native disturbances, those in the North Island have generally been of little use to the colonists, although they are frequently resorted to by the natives; and I fear that it will take some time, from the two principal obstacles alluded to, before the colonists will be able to visit them with comfort and safety.
Of the thermal springs in this island, those of the Hanmer Plains, in the Amuri District, Province of Nelson, are the best known; but hitherto, from various reasons, of which I shall presently speak, they have been in most instances of no avail to those of our suffering fellow colonists who were in need of such remedies as they afford for the restoration of their health.
During a geological examination of the Amuri District, undertaken for the Geological Survey of New Zealand, I paid a short visit to these springs, and examined them as well as the means at my command would allow, and I now lay the observations I made before the Association. I hope at the same time, that these few notes will assist in making these valuable thermal waters—the healing qualities of which have in many cases been proved in a most remarkable manner—more accessible to suffering humanity.
The Hanmer Plains are about fifteen miles long, and two to three miles broad, and are without doubt a former lake basin, in which the Waiau-ua, the Hanmer, and some other smaller streams emptied themselves.
This lake, partly filled up by the detrital matter brought down by the rivers, at last cut the channel of its outlet so deep that it could empty itself by the gorge of the Waiau-ua, by which process the plains were formed as we now see them. The River Waiau-ua passes through their western side in a west and east direction, to about their central part, when it turns rapidly at right angle to the south, passing through the picturesque gorge over which Mr. Blackett, the Provincial Engineer of Nelson, has built that splendid bridge— the admiration of every traveller who passes that way.
However, before the Waiau-ua enters the gorge, it is joined by the River Hanmer, a small mountain torrent running in the opposite direction to the main river, namely, from east to west.
The shingle terraces by which these rivers are enclosed on both sides are
high and abrupt towards the south, where they ascend to an altitude of about 120 feet, rising gently on the northern side, and forming a shingle plain, with a great deal of swampy ground, cut through by numerous smaller rivulets and creeks.
The whole plains are surrounded by ranges 4000 to 6000 feet high, consisting of younger palæozoic or older mesozoic rocks, which, in many localities, are cut through by diorites, amygdaloids, and other trappean rocks.
About three miles in a north-east direction from the beginning of the Waiau-ua Gorge, and about 200 yards from the foot of the northern ranges, the thermal springs are situated. They occur over an area of about 2000 square yards, in a perfectly dry position, at an altitude of 1162 feet above the level of the sea, as calculated from a single barometrical observation. They are situated about five feet below the surface of the plains, and on a line running north-east to the south-west. There are four principal basins, having four smaller ones close to them, the outlets of which join together and form a swampy creek running into the Percival, one of the tributaries of the Hanmer.
We may safely assume, from the geological features of the country in which these springs take their rise, that they issue from a fault or fissure in the older sedimentary beds which has been formed in connection with trappean rocks, making their appearance at various intervals towards the close of the mesozoic period.
I have been informed that some other springs of similar nature occur on the northern side of the Percival Range, as well as on the southern banks of the Hurunni, above Lake Sumner, and these probably owe their origin to the same agencies.
Whatever their origin may be, these springs are very different from those of the lake regions in the North Island, which stand in close connection to the volcanic action still going on in that part of New Zealand.
The principal spring of the Hanmer Plains is situated in the north-eastern corner of the area. This basin has an average breadth of twelve yards. The water which it contains is perfectly colourless at the shallow sides, whilst towards the centre, which is much deeper, it has a beautiful greenish blue tint. It has a well-defined taste and smell of sulphuretted hydrogen. In the centre, at several spots, the water rises, continually throwing up large bubbles. Temperature on the sides, 97° 2′; in the centre, amongst the bubbles, on bottom, 104° 1′. Depth about eight feet. Temperature of air, 70° 3′; sky overcast.*.
This largest basin, No. 1, is the one which has principally been used for
[Footnote] * I may here observe that I made the observations in the centre of the basins with a good self-registering thermometer of Negretti and Yambra, which we let down (Mr. Hugh M'Ilraith, who was my companion that day, kindly assisting me) by a flax rope drawn across the basin, and to which I had tied the instrument
bathing purposes. Unfortunately, there is not the least facility for its use, as the small hut which one of the patients had built upon its banks has since been destroyed. The nearest locality where patients can find quarters is an accommodation-house, a few miles distant. It is therefore impossible for delicate patients to make any use of the springs at present, except under the most unfavourable circumstances, and with the imminent danger of aggravating their complaints by taking cold.
But notwithstanding all these great disadvantages, this basin has restored the health of many persons coming from various parts of New Zealand, and even from Australia. The greater number of the patients were sufferers from acute or chronic rheumatism, boils, and similar disorders; and from all I could learn from a few of them, and from some gentlemen in the neighbourhood, whose authority is reliable, the waters in most cases had a wonderful effect. It seems, therefore, that in many respects the springs may be compared with those of Aix-la-Chapelle, in Germany, and Cheltenham and Harrowgate, in England, which are used for the same complaints, and the principal mineral contents of which are sulphuretted hydrogen. Every well-wisher of the colony will, I am sure, share my sincere regret that these springs are still in their natural state, or even worse, being much disturbed by cattle, and that no means have yet been taken to have them enclosed, proper buildings erected near them, and to make their existence known over New Zealand and the Australian colonies.
Close to the large basin, No. 1, are two small shallow pools, one of which is situated at the south-eastern corner, and is only a few feet in circumference. The water, which rises in it in a few bubbles, has the same taste and smell as the main basin, with a temperature of only 78° 3′. This lesser degree of heat may be accounted for by the circumstance that the water rises only in small quantities in this spring, which has, like the preceding one, a fine muddy bottom.
Another small basin, No. 3, is situated at the eastern extremity of the principal basin. Its water showed a temperature of 106° 8′, and exhibited all the same properties which characterize the first described spring.
About fifty yards to the south of No. 1 is another basin, which has a diameter of ten feet. Numerous bubbles rise in and near its centre, where I found the temperature to be 103°, whilst on the shallow sides it diminished to 98° 1′. The water of this basin is also clear, and, although still showing the presence of sulphuretted hydrogen, this peculiarity is much less predominant than in that of the previously described springs. Its outlet is well defined, joining, after a course of about thirty yards, the swampy creek which flows from No. 1.
About thirteen yards from No. 4, in a south-west direction, another small basin is situated; it is very shallow, and the water (which has only a
temperature of 68° 9′) seems quite tasteless. Moreover, it has no outlet, the spring which feeds it being very small.
Still advancing seven yards towards south-west, we reach No. 6, a small intermittent spring, temperature 102° 2′, which fills a shallow basin about two feet in diameter. It is also strongly impregnated with hydro-sulphuric acid. In the outlet of this spring, which runs about three yards and falls into another larger basin, which I shall presently describe, a white powder is deposited, but of such a small extent that to collect some of it would have taken more time than I had at my disposal.
This is, as far as I am aware, the only spring where such deposits are formed, which, if carefully collected, would afford us reliable information concerning its mineral contents.
The next spring, No. 7, into which the outlet of the former falls, has formed a basin of a diameter of ten feet. Owing to the constant ebullition in many spots over its surface, the water it contains has a muddy appearance. It is the warmest of the whole series, registering 110° 5′ in the centre, whilst on the sides it falls to 94° 6′. It also shows the same characteristics of mineral contents as the foregoing springs. Its outlet, after the course of a few yards, joins the main creek.
Crossing this swampy watercourse, and ascending on its right bank, we soon reach basin No. 8, situated thirty-five yards from the north-east corner of No. 1. It is the second largest basin of the whole series, having a diameter of eighteen to twenty feet. Although numerous bubbles rise in different spots near its centre, so that it almost appears as if it were boiling, by which means the water is kept in its turbid state, its smell is less strong, and its taste purer than the former. I found the temperature in the centre 99° 7′, and on the sides 97° 8′, consequently very little difference all over the basin. On its western banks, a smaller shallow basin is attached to it, containing muddy water, strongly impregnated with sulphuretted hydrogen; temperature 99° 8′.
There is no doubt that, owing to the position of the springs, the water is not only greatly cooled by having to pass through a considerable thickness of sand and shingle, but also from the porous nature of the ground a further important dimunition in its temperature takes place by mixing with the leakage and surface waters.
This disadvantage also causes the mineral properties of the waters to be much diminished. Consequently, if the springs were properly enclosed so that they could rise unmixed to the surface as they issue from their rocky orifice below the shingle, they would improve in quantity and quality, as well as in temperature, and thus also doubtless in efficacy.
May I be allowed so suggest to the Association, the importance of having these springs properly surveyed, and of having collected from each a small quantity of water in well cleaned and corked bottles, to be sent to the Colonial
Laboratory for analysis, so that their mineral contents can be compared with those of well known springs in the northern hemisphere. I shall be truly gratified should these few notes assist in drawing the attention of the Provincial Government of Nelson to the great treasure it possesses in these springs, and that they may thus be made accessible to those of our suffering fellow colonists, who have hitherto only been deprived from using them by the neglected state in which they have been allowed to remain for years.
Further Notes on the Thermal Springs of the Hanmer Plains,
[Read October 5, 1870.]
“In reply to your request for any information I possess relative to the hot springs which occur on the Hanmer Plains, I beg to inform you that I examined them on the 8th May, 1867, and made the following notes at the time :—
“The altitude of the springs above the sea I found to be 1360 feet, and about 110 feet above the level of the neighbouring river. They occur on flat terrace land, under the range of hills that bounds the valley on the north side near where they are crossed by Jollie's Pass, leading to the Valley of the Clarence. I made my observations early in the morning, the temperature of the air being 52† F.
“1. A shallow muddy pool, twelve feet in diameter. Temperature, 50†5.
“2. At thirty feet distance from the above, and six feet lower, a pool of circular form, six feet in diameter, and more than eight feet deep, has a steady overflow and constant escape of bubbles of sulphurous steam. Temperature, 89†3.
“3. Twenty feet across, and seven feet deep close to the bank. Temperature, 89†5.
“4. Eighteen feet across, and more than ten feet deep. Temperature, 88†5.
“5. Several small pools around the sides of the two last, had a temperature of 90†5.
“There are, in all, three large holes and four small, the latter being about four feet in diameter.
“Four hundred yards to the east is an intensely green and cold spring, the water of which has a temperature of 43†, while the water in the neighbouring creek was 49†.
“The terrace on which these springs occur is composed of gravel and sand, and there is no appearance of any outcrop of rock nearer than the foot of the spur, which is 400 yards distant. There is no large deposit of silica from these springs as in the case of the geysers in the North Island. A small quantity of the water from the hottest spring was obtained for analysis, and gave the
following results :—Character: transparent, colourless, and tasteless; decidedly alkaline to test-paper. A flocculent precipitate had settled, the amount of which was equal to 2.11 grains upon the gallon, and principally silica. The quantity of water was too small to allow of a proper analysis; but the total of fixed matters in solution was equal to 86.4 grains per gallon, of which only 2.88 grains was silica. The remainder was alkaline chlorides and sulphates, but carbonate and sulphate of lime was present in moderate quantity, and the chlorides of magnesium and iron in much smaller proportion. Iodine was tested for with negative results, but it could hardly be discovered in so small a sample, unless present in notable quantity.”*
[Footnote] * The difference in the temperature of these springs as observed on this occasion from that recorded by Dr. Haast, appears to indicate that they are intermittent and variable in their temperature.—Ed.