ON UNDERGROUND TEMPERATURE. 69 



and hauling it up again disturbs the contents of the bore at all parts 

 above this point, the general rule is to take the shallowest observation 

 first and work downwards. On the other hand, when there is danger 

 of caving in, it may be desirable to begin Vjy securing the most valuable 

 observation — that is, the deepest — and to work upwards This latter 

 was the order of observation adopted at Paruschowitz, the points of 

 observation being at the uniform distance of 31 metres, the lowest at 

 1,959 metres, and the highest at 6 metres. This makes sixty-four determi- 

 nations, each being the mean of six readings. 



Though the observations were taken under less favourable conditions 

 than those at Schladebach, they are of very unusual interest, and the 

 withholding of them from publication till the present time is a notable 

 instance of excessive modesty. When they are plotted the curve obtained 

 exhibits a sarisfactnry amount of regularity, and does not depart very far 

 from a straight line joining its two ends. Of the two most conspicuous 

 irregularities one extends over the portion where 183 metres of tubing 

 were broken away the temperature here being a degree or two higher 

 than one would have expected — and the other at the point where the 

 change was made from wrought-iron rods to Mannesmann steel, the in- 

 terval between the two consecutive temperatures on opposite sides of this 

 point being about three times the average interval. Several other points 

 can be selected which show an excess or defect of temperature amounting 

 to 1°, but this is only what was to be expected from the alternations of 

 different rocks. In some condensed reports of Bergrath Kobrich's com- 

 munication (but not in the full paper as given in ' Gliickauf ') the irregu- 

 larities are attributed to chemical action in the coal seams, causing in 

 some cases a heating and in others a cooling ; but in the absence of more 

 direct evidence this explanation seems rather forced. 



The curve for the shallower portion from 6 metres to 533 metres is 

 approximately a straight line of gradient 1° C. in 39 '6 metres ; while the 

 curve for the deepest portion — 1,680 metres to 1,959 metres — shows an 

 average gradient of 1° C. in 31 "0 metres. The intermediate portion — 

 533 metres to 1,680 metres (which is rather more wavy)— has an average 

 gradient of 1° C. in 32-9 metres. 



Comparing the shallowest observation, 12°'l at 6 metres, with the 

 deepest, 69°-3 at 1,959 metres, we have an increase of 57°'2 in 1,953 metres, 

 which is at the rate of 1° C. in 34-1 metres, or 1° F. in 62-2 feet. This 

 general average is the only result that has hitherto been published. 



No doubt seems possible as to the correctness of the determination 

 69°-3 at 1,959 metres. The firmness of the clay, being sufficient to pre- 

 vent a hollow rod weighing several tons from going deeper, must have 

 been sufficient to prevent convection. 



As regards the determination 12°'l C. at 6 metres, one naturally 

 compares it with the temperature found at precisely the same depth in 

 the Schladebach bore, which was 8°-3 R., or 10°*4 C. Paruschowitz is a 

 degree or degree and a half further south than Schladebach, but is 152 

 metres higher, which about compensates the difference of latitude, so that 

 one would expect their temperatures to be the same. Further light is 

 thrown upon the question of the temperature of Paruschowitz by com- 

 parison with the known temperatures of places lying around it. 



The following particulars respecting neighbouring places and their 

 mean annual temperatures are taken from Hann's ' Klimatologie ' 

 (Stutgart, 1897), vol. iii. p. 147 :— 



