rmous fissures in colossal masses of highly polished yellow
lava. After solidification these masses of lava had been subjected to
violent commotion, as their stratification was nearly in a vertical
position.

Wherever possible I took observations for latitude and longitude, in
order to ascertain my exact position; an 8-in. sextant, mercurial
artificial horizon and chronometers being used for the purpose. It is not
easy to describe the torture I had to go through when taking those
tedious astronomical observations. The glass roof of the artificial
horizon had unfortunately got broken. I had to use a great deal of
ingenuity in order to screen the mercury from the wind so as to obtain a
well-defined reflection. No sooner was I getting a perfect contact of the
sun's image and its reflection than some huge fly or other insect would
begin to promenade on the mercury, disturbing its surface. Butterflies
were even more troublesome, as they left upon the mercury--by the
luminosity of which they were greatly attracted--sediments of
multi-coloured powder and down from their wings and bodies. The mercury
had to be carefully re-filtered before work could proceed. Then, what was
worse, when both your hands were occupied--one holding the sextant, the
other gently screwing the vernier--hundreds of mosquitoes, taking
advantage of your helpless condition, buzzed round and settled on your
nose, ears, neck, eyelids and forehead, stinging you for all they were
worth. Swarms of bees--a dwarf kind, with body in yellow and black
stripes; fortunately these did not sting--also placidly roamed upon every
available patch of skin with a provoking tickling. A great number of them
settled along the edges of the eyelids, attracted by the sheen of the
retina of the eye, into which they gazed with great interest. Others,
more inquisitive, would explore the inside of your ears; while
millions--actually millions--of _pium_, the tiny gnats--more impertinent
than all the others taken together--dashed with great force up your nose,
into your eyes, into your mouth, and far into your ears, and were most
troublesome to remove. Your ankles and knees and wherever the skin was
soft were itching terribly with _carrapatinhos_, and before you got
through with your work you were also swarming all over with ants of all
sizes--careering all over your body and inflicting painful bites whenever
you placed your hand upon your clothes to arrest their progress. When you
had