72 Dr Paterson on the Temperature of 



regarding these springs, that the following observations have 

 been drawn up. 



It has already been mentioned that M. Arago was the first 

 who supported the idea that the temperature of the water, 

 issuing from an artesian well, is the means least liable to give 

 fallacious results of any which have been yet proposed, to as- 

 certain the increased temperature of the centre of the earth. 



If the water, as it makes its exit from the mouth of a 

 bored well, possesses a temperature above that of the sur- 

 rounding atmosphere, it must have acquired that temperature 

 from the rock out of which it came. But two very import- 

 ant objections have been urged against its possessing precisely 

 the same temperature as the rock which contained it. First, 

 That frequently springs coming from a higher level mix, and 

 consequently modify the temperature of the water. Second, That 

 water coming from a great depth, loses a certain degree of its 

 temperature in imparting it to the cooler sides of the perforation. 



That such objections might not be brought against this 

 species of information, we used an instrument which has been 

 long known for ascertaining the temperature of water at great 

 depths. It consists of a glass-tube with brass ends which 

 screw on ; in each of these ends there is placed a valve, and 

 both of the valves open upwards. It contains a thermome- 

 ter, and is surrounded with a non-conductor ; a string being 

 attached to it, it is lowered down into the bored well. The 

 water rushing up the bore, together with the instrument de- 

 scending against it, causes both valves of the instrument to 

 open, by which a free communication through the instrument 

 by the valves is kept up, until it reaches the bottom of the 

 perforation. The instrument is to be allowed to remain there 

 for a short time, and then withdrawn as quickly as possible. 

 As soon as we begin to withdraw this instrument, the valves 

 close, and consequently include a quantity of water from the 

 lowest level, at which it has been. 



We have used the above described instrument on many 

 different occasions, and in many different artesian wells, both 

 those of recent and of several years' formation, and on no occa- 

 sion did we find the slightest difference of temperature, be- 

 tween the Avater taken at the mouth of the bore, and that 

 brought up by the instrument. 



