"Why not?" asked Nicholl.

"Because, if we are passing through an atmosphere of the
slightest density, these objects will be retarded. Again, the
darkness prevents our seeing if they still float around us.
But in order not to expose ourselves to the loss of our
thermometer, we will fasten it, and we can then more easily
pull it back again."

Barbicane's advice was followed. Through the scuttle rapidly
opened, Nicholl threw out the instrument, which was held by a
short cord, so that it might be more easily drawn up. The scuttle
had not been opened more than a second, but that second had sufficed
to let in a most intense cold.

"The devil!" exclaimed Michel Ardan, "it is cold enough to
freeze a white bear."

Barbicane waited until half an hour had elapsed, which was more
than time enough to allow the instrument to fall to the level of
the surrounding temperature. Then it was rapidly pulled in.

Barbicane calculated the quantity of spirits of wine overflowed
into the little vial soldered to the lower part of the
instrument, and said:

"A hundred and forty degrees Centigrade [4] below zero!"

[4] 218 degrees Fahrenheit below zero.