30 Oit tlic Chcmival Cmisfi(7ifii)ii and 



earth, by calculation, we may suppose its interior to consist of 

 materials of the densest kind, which are the best conductors of 

 heat. But were this not the case. Von Hoff continues, yet 

 the continued exit of so considerable a quantity of heat, as 

 that which the springs of Carlsbad discharge from the earth, 

 must produce a considerable cooling in its interior, if the 

 warmth was not continually generated. But since we have 

 known these springs there has not been the smallest gradual di- 

 minution of temperature, or any of the other effects, nor, conse- 

 quently, of the activity of the process ; on the contrary, their 

 force during the last century, since which their phenomena have 

 been more accurately observed, and viewed by more experienced 

 naturalists than formerly, has continued undiminished, and in 

 this period several new and permanent hot springs have burst 

 forth, without those already existing having ceased yielding watei- 

 of the same quality as before. 



That these objections are weighty cannot be denied ; but as 

 throughout nature, when we attempt to estimate things on the 

 large scale, for which a sure criterion is wanting^ false conclu- 

 sions may easily be made; while, on the contrary, quantities 

 found by incomplete experiments may more certainly guide us, 

 I instituted the following experiments. 



I brought basalt in a wind furnace, to the strongest white 

 heat, till it began to melt, and then suddenly plunged it into a 

 measured quantity of water, of a known temperature, contained 

 in a cylindrical vessel, constructed of cast brass, on which was 

 fitted an air-tight cover of the same metal. Immediately after 

 the immersion of the glovvlng basalt in the water, the cover was 

 applied, in order to prevent the escape of steam, and by that means 

 of heat. On a thermometer, inserted in an oi)ening of the 

 cover, the bulb of which leached the water, I observed the in- 

 crease of temperature as long as the hissing noise of the glow- 

 ing and gradually cooling basalt was heard. The following 

 are the results : — 



1. A piece of basalt, 9 oz. weight, heated to a bright red, 

 was plunged in 93-75 oz. of water, of 17°.7 R. The tempera- 

 ture of the water increased to 31°.2 R. 



2. A second piece of basalt, 9 oz. weight, was heated till 

 some melted portions dropt off, and immediately put in 112 oz. 



i 



