The universal geography : earth and its inhabitants

ICELAND. 33Amongst the thousands of hot springs whose waters trickle away into hiddenlakes, streamlets, or the sea, some have become famous under the name of geysers,natural springs of water suddenly thrown up by the imprisoned vapours. In therecords of the thirteenth century occurs the first allusion to the Great Geyser,which is situated in the south-west part of the island, in the middle of a plainintersected by the river Hvita, and enclosed on the north side by the long ridge ofthe Blafell. It may have then made its appearance for the first time, but hasnever since ceased to act, at each eruption depositing a slight siliceous crust aroundits orifice. Thus has been gradually formed a margin now no less than 40 feethigh, whence is visible the interior of the well full of boiling water at the periodsof eruption. Previous to the jet the vapours are seen to rise in clouds, thendissolve, and form again. Suddenly the resistance of the upper water is overcome,and the column of deep vapours, 58° above boiling point, bursts upwards, bearingwith it, to the height of 100 feet, a volume of water estimated at upwards of 60 tonsin weight. Since the days of Olafsson and Palsson the descriptions of observersdiffer remarkably from each other. Those travellers saw a jet 360 feet high,while more recent accounts speak of heights not exceeding 60 feet, sothat the Great Geyser would seem to be subsiding. The neighbouring geyser,named by the peasants the Strokkr, or " Churn," formerly sent up jets as high asthe more famous spring ; now it emits its vapours regularly, but withoiit anysudden or violent eruption. The " Little Geyser," spoken of by travellers of thelast century, completely disappeared after an earthquake which occurred in 17S9.But a great many lesser " churns " still bubble in the plain, filled with waters ofdivers colours—red, green, blue, or grey—which are thrown up to various heightseither freely or when excited by the stones or mud cast in by visitors. A greatunderground lake is spread beneath the whole district, and it sometimes happensthat the unwary traveller sinks through the treacherous crust, and finds himselfsuddenly plunged into a hot spring beneath. An island in the neighbouring lakeis entirely formed of siliceous incrustations deposited by deep underground springs.About midway between the Geyser district and Reykjavik is found one of thegeological curiosities as well as the most memorable historical spot in the island.This is the pingvalla, or " Assembly Plain," enclosed on the south by the largestlake in Iceland. This plain, several miles broad, was formerly the bed of amighty lava stream, the remains of which are still visible. Both sides of the bedrise abruptly to a height of 100 feet, here and there presenting arcades and basaltcolumns which resemble regular buildings. Between the walls and the remains ofthe lava stream there yawn deep cavities formed by the central mass contractingfrom its sides in the process of cooling down. Thus were produced the greatlateral fissures of Almannagja, 5 miles long, and Hrafnagja, parallel and east ofbesides the various crevasses occurring here and there in the lavas of the plain.it,Three of these fissures are so connected as almost completely to isolate a huge lavablock now overgrown with grass. This block, connected by a narrow isthmuswith the rest of the stream, is the Albing, a natural stronghold chosen by theancient Icelanders as the site of their National Parliament. A hillock at the