Letters on Iceland: containing observations on the civil, literary, ecclesiastical, and natural history; antiquities, volcanos, basaltes, hot springs; customs, dress, manners of the inhabitants, &c. &c / Made, during a voyage undertaken in the year 1772, by Joseph Banks, assisted by Dr. Solander, Dr. J. Lind, Dr. Uno von Troil, and several other literary and ingenious gentlemen. Written by Uno von Troil. To which are added the letters of Dr. Ihre and Dr. Bach [i.e. Bäck] to the author, concerning the Edda and the elephantiasis of Iceland: also Professor Bergman's curious observations and chemical examination of the lava and other substances produced on the island. With a new map of the island, and a represtation of the remarkable boiling fountain called by the inhabitants geyser.

Uno von Troil

Date:: 1780

Credit: Letters on Iceland: containing observations on the civil, literary, ecclesiastical, and natural history; antiquities, volcanos, basaltes, hot springs; customs, dress, manners of the inhabitants, &c. &c / Made, during a voyage undertaken in the year 1772, by Joseph Banks, assisted by Dr. Solander, Dr. J. Lind, Dr. Uno von Troil, and several other literary and ingenious gentlemen. Written by Uno von Troil. To which are added the letters of Dr. Ihre and Dr. Bach [i.e. Bäck] to the author, concerning the Edda and the elephantiasis of Iceland: also Professor Bergman's curious observations and chemical examination of the lava and other substances produced on the island. With a new map of the island, and a represtation of the remarkable boiling fountain called by the inhabitants geyser. Source: Wellcome Collection.

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[ .3S2 ] liquid mafs whilfl it is cooling : and 3dly, the burfting of a moift fubflance whilfl: it is drying. The firfl: method is the moft com- mon, but to all appearance Nature has not made ufe of this in the prefent cafe. Cryftals are feldom or never found in any confiderable quantity running in the fame direftion, but either inclining from one another, or, what is ftill more common, placed to- wards one another in feveral floping direcflions. They are alfo generally feparated a little from one another, when they are regular; the nature of the thing likewife requires this, becaufe the feveral particles, of which the cryflals are compofed, mufl: have the liberty of following that power which affects their regular difpofition. • - : The bafalt columns, on the contrary, Avhofe height are frequently from thirty to forty feet, are placed parallel to one another in confiderable numbers, and lb clofe together that the point of a knife can hardly be introduced, be- tween them. Befides, in mofl; places, each pillar is divided into feveral - ..V parts

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