part 1.] Medlicott: Observations on Underground Temperature. 
47 
Khappa bore-hole .—As the deepest boring of all, this was the one I was most anxious to 
observe in ; and the failure is partly due to over-caution. At the close of last season (31st 
May) this hole had reached the depth of 633 feet. I had requested that it might be securely 
closed; and this was so effectually done that it took five hours battering with hammer and 
chisel to remove the wooden plug. These shocks must have vibrated through the tube, with 
which the hole is lined to a depth of 270 feet, and thus disturbed the partially unstable 
equilibrium in the column of water upon which the result of observations in these small¬ 
bore sinkings depends. It would seem even that something more than active convection was 
thus produced: after the thermometers had been down for fifteen minutes at the 200 feet 
position, a strong bubbling set up both within and around the tubing, and the water rose 
three or four inches. This occurred 13 hours after the tube had been opened. Tbe reading 
then taken (the upper one of the table), at 11 p.m., showed an exceptional rise of tempera¬ 
ture ; and the next reading, at 250 feet, showed an equally exceptional fall of temperature. 
Both these points were observed again in the forenoon of the following day, with very 
different results (the lower readings of the table), and probably nearer to the normal state 
of the temperature. All the readings, however, about this depth (150' to 250'), if compared 
with the corresponding readings in the Manegaon bore, and with the sudden rise in the read¬ 
ing at 300 feet, suggest a zone of slow percolation of surface waters. The necessity to 
introduce piping to the depth of 270 feet is probably connected with this water-pressure. 
Nothing was noticed in the samples of rock from these depths to suggest a local cause for 
such percolation. The sandstones and clays have the same average characters and alternat¬ 
ing arrangement as throughout the boring. The reading at 300 feet in Khappa is probably 
a true earth-temperature. It agrees remarkably with the corresponding one at Manegaon. 
Another disappointment connected with the Khappa bore-hole was, that it bad filled up 
with mud to a depth of 260 feet. The observation at 370 feet was the lowest that could be 
taken. 
The observations at Khappa were made on the evening of the 4th and morning of the 
5th December. The air temperature was above 90° in the day; 75° at 5 p.m.; and 52° at 10 
p.m.; 62° at 8 next morning; and 78° at 10 a.m. 
Manegaon bore-hole .—Everything was favourable for satisfactory observations in this 
boring, except that the hole had silted up to a depth of 110 feet, its full depth having been 420 
feet, while the lowest observation obtainable at the time of the observations was 310. It 
was closed on the 24th of April 1875; so that it had been at rest for 20 months. There is 
only one guide-pipe, ten feet long, at the top of the bore, there never having been any pres¬ 
sure of water in the hole. The position is low, and the water had always stood at or near 
the mouth of the tube. There was no difficulty in removing the plug. 
The very equable series of temperatures is the natural result of these conditions. The 
observations were taken in the evening of the 5tli and morning of the 6th of December. At 
5 p.m., the air temperature was 72°; at 8 p.m., 59°; at 8 a.m., 65°; at 11 a.m, 84°. 
Tbe slight decrease of temperature in the top readings is a good proof of the perfectly 
tranquil conditions of observation. It is no doubt due to the excess of summer heat not 
yet abstracted; and it is apparent that that influence reaches to a considerable depth—quite 
to 60 feet. With a specially sensitive thermometer, the range of its variation might, no 
doubt, be determined with much accuracy in such a boring. 
An idea of the climatal conditions may be obtained from the following abstract of 
observations at the two nearest meteorological stations, kindly furnished to me by Mr. H. F. 
Blanford. Khappa and Manegaon are two miles apart, and at about the same level, in an 
