( 179 ) 



On the Temperature of the Geyser Springs in Iceland, 



M. Flourens communicated to the Academy of Sciences on the 

 16th of November, the results of some observations of MM. Descloi- 

 zeaux and Bunsen last July, on the intermittent boiling springs of 

 the Geyser and Strockr,* the latter being within 140 yards of the 

 Great Geyser. f The observations were on the temperature of the 

 water, in the great column or well of each, made by suspending ther- 

 mometers at different depths, at different times, before and after 

 eruptions. The Great Geyser has a depth of 22 metres (72 feet), 

 and the experiments shewed that the temperature of the column di- 

 minished gradually from the bottom upwards, and that the maximum 

 temperature at the bottom before a great eruption was 127°*6 Centi- 

 grade (260^-° Fahr.), and the minimum 122° (251J° Fahr.), after 

 an eruption. The temperature of the water at the surface was 85°*2 

 (185° Fahr.), when that at the bottom was 127° C. 



After an eruption, the lowest thermometer stood at 121°*6 (251^^ 

 Fahr.); nine hours afterwards at 123°-6 (254-J° Fahr.). Between 

 11 o'clock A.M. of the 6th July, and 2*55 p.m. of the 7th, there was 

 no eruption, so that there had been an interval of nearly 28 hours ; 

 and the water at the latter time, at the bottom, was 127°'6 (261|-° 

 Fahr.) ; a quarter of an hour afterwards there was a slight eruption. 



The Strockr is a circular well 44|- feet deep, with an orifice of 

 about 8 feet, which rapidly diniinishes downward, and at about 27;^ 

 feet from the surface the orifice is only 10^ inches. The column of 

 water between the eruptions has a mean depth of 27|- feet, so that 

 its surface, which is in a constant state of ebullition, is generally from 

 10 to 13 feet below the surface of the ground. The temperature of 

 the water at the bottom varied from 112°-9to 114°-2 (235° to 237^° 

 Fahr.), and the same temperature continued throughout a depth of 

 about 20 feet, when it began to sink, and at the surface of the w^ter 

 the thermometer stood at 100° (212° Fahr.). 



These observations on the temperature of the water are highly 

 curious and important. We have a temperature of 261° Fahr. at 

 the bottom of a free open column of water, in which thermometers 

 could be suspended on a lino dropped from the surface, while it might 

 have been expected that, as soon as a film of water at the bottom 

 was raijscd to a higher temperature, it would ascend, and be replaced 

 by a colder and heavier film, and that thus a constant current would 



* It is called Strokkus in the Comptes Rendus, but Henderson calls it Strockr, 

 and says the name is derived from the verb " Strocka," to agitate, or bring into 

 motion. 



t Henderson's Iceland, p. 69. 



