Penny Blood: Serial Sensation and Working-Class Entertainment — page 26: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

cH.1.]| ON UNDERGROUND TEMPERATURE. 9 The consequence would be that the open surface of the water would be cooled, sensibly to the temperature of the air. This would bring the curve of temperature of the water at the surface nearly to the same point as the temperature line of the rock there, and it would also have the effect of reducing the tem- perature of the water throughout the column, below what it would be if it had not this extrinsic cause of cooling. The ultimate result would be that the temperature curve of the water would assume some such form and position as AF’. It will be ob- served that this line also intersects AC; and the signification of this is, that the water in the bore-hole is warmer than the rock mass in its upper portion, and cooler than the rock mass in its lower portion; or, in other words, the water tends to warm the rock in the upper portion, and to cool it in its lower portion. Consequently, if the circulation of the currents be interrupted, the water imprisoned between the disks of the geo-thermometer would in the upper portion of the hole gradually become cooler, as heat was conducted away from it into the body of the rock ; and it would gradually become warmer in the lower portion, as heat was conducted into it from the body of the rock. But at the particular depth at which the two lines AC and AF intersect no alteration would take place. That such an effect was actually produced is shown by the following table, the first two columns of which are taken from Dunker’s Table II., in his paper entitled “ Ueber die Benutzung tiefer Bohrlécher zur Ermittelung der Temperatur des Erdkér- pers, und die desshalb in dem Borloche I zu Sperenberg auf Steinsalz angestellten Beobachtungen.” The two temperatures marked with asterisks differ from those quoted in the British Association Report from Dunker’s quarto paper of 1872 in the “ Zeitschrift fiir Berg-Hiitten und Salinen-Wisen.” But they are printed as here given in the octavo paper from which they have been copied, and are stated there to be the mean results of several observations. Dunker considéred the deepest observation with the geo-thermometer unsatisfactory. The difference between a Prussian and an English foot is so small that, for the purpose in hand, they may be considered equal, . GONG oOo SS (CO)