While engaged in the discovery that this style of dress is not without its drawbacks, I found, to my surprise, that the direction of the current suddenly changed, and the cold blast which had before blown out of the cave, now blew almost as strongly in.

The arch of entrance was so low, that the top was about on a level with my waist; so that our faces and the upper parts of our bodies were not exposed to the current, and the strangeness of the effect was thus considerably increased.

As a matter of curiosity, we lighted a _bougie_, and placed it on the edge of the snow, at the top of the slope of 3 or 4 feet which led down the surface of the ice, and then stood to watch the effect of the current on the flame.

The experiment proved that the currents alternated, and, as I fancied, regularly; and in order to determine, if possible, the law of this alternation, I observed with my watch the exact duration of each current.

For twenty-two seconds the flame of the _bougie_ was blown away from the entrance, so strongly as to assume a horizontal position, and almost to leave the wick: then the current ceased, and the flame rose with a stately air to a vertical position, moving down again steadily till it became once more horizontal, but now pointing in towards the cave.