1814.] and on Vegetation, 2$ 



ture of the earth may be determined, by examining them at their 

 origin, and the many interesting consequences which he has drawn 

 from a collection of such temperatures, are decisive proofs of what 

 may be done with a thermometer alone, without the assistance of 

 any other instrument. Lbopold Von Buch. 



I. 



Observations on the Heat of Springs, and the Temperature of the 



Earth, at Upsala, and at the Yngen Lake, in IVermeland. By 



George Wahlenberg.* 



That the climate can be determined with the greatest precision 

 by means of the plants which vegetate in any country, and that 

 observations on the distribution of plants in different countries serve 

 excellently to distinguish the climates of these countries from each 

 other, scarcely require any proof. These observations on vegeta- 

 tion, indeed, do not furnish us with particular facts applicable to the 

 whole surface of the earth, because it often happens that the same 

 plants are not found in similar, but far distant, latitudes. 



The temperature of the earth constitutes a much simpler measure, 

 which is more easily determined, and is most intimately connected 

 with the vegetation of plants. It constitutes, as it were, the mean 

 between the peculiar temperature at which plants grow, and that of 

 the atmosphere which surrounds them. Such determinations of the 

 temperature of the earth furnish grand points in a chart of the 

 climate of the country; while from the relations that plants bear to 

 each other, the intervals between these points might be filled up. 

 In order to satisfy myself fully of the truth of these observations, I 

 have endeavoured to determine the temperature of the earth in the 

 two places with the vegetables of which I am best acquainted, 

 namely, at Upsala and at the Yngen lake, in the parish of Kroppa, 

 which is under the mining jurisdiction of Philipstadt, in Werme- 

 land. 



The greatest spring at Upsala, in respect of the quantity of water 

 which it contains, is the Brennerei (distillery) spring, or as^ it is 

 also called, the Sanduiks (sandy) spring. It forms at once a rivulet 

 which is always capable, even at its source, of driving a small mill 

 1 have made the following observations on this spring. Its tempe- 

 rature was — 



1808. Temperature 1800. Temperature. 



30 March 43-9° 30 January . . . .44-0«° 



10 May 44-06 28 February . . .44*24 



6 June 43-«J 30 March 44*06 



25 Ditto 44-06 27 April 44*06 



17 July 44-06 15 August 44-24 



14 August 44*24 16 September . .44-24 



1 1 September . . .44-24 14 October 43*9 



* Kon K l. Vctensk. Acad. Nya Ilnndl. 1800, f, SOf). 



