Page:Passages from the Life of a Philosopher.djvu/236

220 at tolerably regular intervals. At first, I performed this operation at a respectful distance and out of the reach of the projected red-hot scoria. But as I acquired confidence in their general regularity, I approached from time to time more nearly to the little cone of scoria produced by its own eruptions.

I now perceived an opening in this little cone close to the perpendicular rock of the interior of the great crater. I was very anxious to see real fluid lava; so immediately after an eruption, I rushed to the opening and thus got within the subsidiary crater. But my curiosity was not gratified, for I observed, about forty or fifty feet below me, a huge projecting rock, which being somewhat in advance, effectively prevented me from seeing the lava lake, if any such existed. I then retreated to a respectful distance from this infant volcano to wait for the next explosion.

I continued to note the intervals of time between these jets of red-hot matter, and found that from ten to fifteen minutes was the range of the interval of repose. Having once more reconnoitred the descent into the little volcano, I seized the opportunity of the termination of one of the most considerable of its eruptions to run towards the gap and cautiously to pick my way down to the rock which hid from me, as I supposed, the liquid lava. I was armed with two phials, one of common smelling salts, and the other containing a solution of ammonia. On reaching the rock, I found it projected over a lake which was really filled by liquid fiery lava. I immediately laid myself down, and looking over its edge, saw, with great delight, lava actually in a state of fusion.

Presently I observed a small bubble swelling up on the surface of the fluid lava: it became gradually larger and larger, but did not burst. I had some vague suspicion that