January 10, at 10.12 A.M. ... 23 deg..684 "
   " " 10.0 " ... 23 deg..9 "
   " " 11.20 " ... 24 deg..022 "
   " " 12.14 P.M. ... 24 deg..134 "
   " " 1.30 " ... 24 deg..35 "
   " " 2.30 " ... 24 deg..584 "
   " " 3.14 " ... 24 deg..8 "
   " " 4.0 " ... 25 deg..142 "

Supposing the weather to have been much the same on the 9th and 10th of January, as M. Thury’s account seems to say, there is something very strange in the great difference between the temperatures registered at 4 P.M. on the one day, and at 7.16 P.M. on the other.

The external temperatures at the mouth of the cave were as follows:—­

January 10, at 10.53 A.M. 25 deg..934 Fahr.
    " " 11.14 " 26 deg..384 "
    " " 11.45 " 28 deg..04 "
    " " 12.32 P.M. 27 deg..944 "
    " " 1.12 " 30 deg..644 "
    " " 3.3 " 26 deg..834 "
    " " 3.56 " 25 deg..7 "
    " " 4.26 " 25 deg..25 "

The minimum temperature of the external air during the night of January 10-11 was 18 deg..392 F., and that of the glaciere 19 deg..76 F.[219] During the preceding night, the minimum in the cave was 22 deg..442 F., which may throw some light upon the difference between the temperatures at 7.16 P.M. on the 9th, and at 4 P.M. on the 10th.

M. Thury bored a hole, of about 10 inches in depth, in the flooring of ice, and placed a thermometer in it, at 12.25 P.M., closing it up with cotton.  At 2.55 P.M., and at 4.7.  P.M., the thermometer marked the same temperature, namely, 26 deg..24 F.

M. Thury’s views on glacieres in general, based upon the details of the three which he has visited, are much the same as those which I have expressed.  He has, however, more belief than I in ‘cold currents.’

FOOTNOTES: 

[Footnote 217:  This was given by a thermometer only placed in the cave at 7 P.M., and by construction not very sensible.]

[Footnote 218:  The moment when the disturbance of the atmosphere commenced.]

[Footnote 219:  M. Thury gives—­4 deg..62 C. as the minimum in the glaciere during the night in question; but on the next page he gives—­6 deg..8 C. (=19 deg..76 F.).  It is evident, from a comparison with other details of his observations, that the latter is the correct account.]

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