Penny Blood: Serial Sensation and Working-Class Entertainment — page 28: what you’re looking at

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

cH.1.] ON UNDERGROUND TEMPERATURE. II on the supposition that the increase per foot remained con- stant for that number of feet ; consequently large numbers show & proportionately slow increase. The seventh column, like the fifth, shows the increase of temperature at the depth against which the number stands, over that at the depth at which the previous number stands; the object of this column being to obtain averages at longer distances apart. The eighth column, like the sixth, shows the rate of increase of temperature with longer averages, measured by the number of feet of descent for 1° Réaumur. The ninth gives the same increase when measured in feet of descent for 1° F. In discussing this table the first point to be noticed is that the rate of ‘increase 1s by no means so equable as, from the homogeneity of the rock, 1t might have been expected to have been. In order to obtain anything like a general law of increase, it 18 necessary to take the average of the increase at considerable distances apart. The second point has been already adverted to, viz., that the shutting-off of the convection currents caused a diminution of temperature in the upper part of the bore-hole, and an in- crease of it in the lower. This shows clearly that the tempera- ture of the rock was altered temporarily, by the action of the convection currents, to some distance away laterally from the bore-hole. The hole was lined with three tubings, one behind another, for the upper 440 feet, and, on account of the pre- sumed convection currents still existing behind the tubing, the observations in the upper part of the column were not considered trustworthy. But this circumstance does not mili- tate against the conclusion at which we have arrived, because whatever effect convection currents might have upon the tem- perature would be pro tanto produced by these concealed currents, so that all they could do would be to lessen the effect of shutting off the currents in the main channel. And we may reasonably suppose that the change of temperature arising from that proceeding would have been still greater than recorded, if the tubing had been in close contact with the rock. GONG oOo SS (CO)