3S6 Prof. Bischof on the Temperature of 



springs are also found in all latitudes : in the polar regions, as 

 in Iceland and in Greenland,* as well as in the temperate zone 

 and under the equator. The heat which accompanies them 

 cannot, therefore, be sought in any particular formation of rocks, 

 nor in local chemical processes, but must be everywhere distri- 

 buted throughout the interior of the earth. We must necessa- 

 rily be brought to this conclusion, so soon as we succeed in prov- 

 ing that it cannot possibly result from any chemical processes. 



Chap. II. — Can the elevated temperature of acidulous springs be a 

 consequence of the absorption of carbonic acid gas? 



Leop. von Buch,*|* in the communication of his observations 

 on the temperature of the springs in the Canary Isles, finds it 

 very remarkable how small a proportion of carbonic acid gas is 

 sufficient to influence the temperature of springs. " But how- 

 ever astonishing," he says, " this circumstance may be, it is ne- 

 vertheless not peculiar to these islands, but, on the contrary, of 

 rather general occurrence. At least I have not as yet been able 

 to discover any acidulous waters, whose temperature has not in- 

 variably exceeded that of the fresh water springs " 



The experiments of Henry,:|: by which he found that carbo- 

 nic acid gas and water of equal temperature, acquired, by their 

 mixture, an increase of temperature of only 0°.45 to 0°-743, 

 were already unfavourable to this hypothesis. However, in or- 

 der to ascertain what increase of temperature would actually re- 

 sult from the absorption of heated carbonic acid gas by water, I 

 formed carbonic acid gas by heating carbonate of lime in a gun- 

 barrel, and made it pass into a receiver filled with water. The 

 quantity of water in the receiver was 174.5 volumes, and that of 

 unabsorbed carbonic acid gas, which had collected over the wa- 

 ter, 60 volumes. The temperature of the water at the begin- 

 ning of the experiment was 44°.375, and after the absorption of 

 the gas 45°.275 ; total increase 0°.9. 



A part of this increase must, however, be attributed to the 

 heat of the room (54°.5 to 56°. 75) during the hour and a half 

 that the experiment lasted, and to the strong charcoal fire neces- 



• Gilbert's Annalen der Physik, vol. Ixii. p. 174. 

 f PoggendorfF's Annal. der Physik, voL xii. p. 415. 

 X Philosophical Transactions for 1803, p. 1. 



