Nevertheless, however pressing was the construction of the vessel, other duties demanded the presence of the colonists on various portions of the island.  Before everything it was necessary to go to the corral, where the flocks of musmons and goats were enclosed, and replenish the provision of forage for those animals.  It was accordingly arranged that Ayrton should proceed thither the next day, the 7th of January; and as he was sufficient for the task, to which he was accustomed, Pencroft and the rest were somewhat surprised on hearing the engineer say to Ayrton—­

“As you are going to-morrow to the corral I will accompany you.”

“But, Captain Harding,” exclaimed the sailor, “our working days will not be many, and if you go also we shall be two pair of hands short!”

“We shall return to-morrow,” replied Cyrus Harding, “but it is necessary that I should go to the corral.  I must learn how the eruption is progressing.”

“The eruption! always the eruption!” answered Pencroft, with an air of discontent.  “An important thing, truly, this eruption!  I trouble myself very little about it.”

Whatever might be the sailor’s opinion, the expedition projected by the engineer was settled for the next day.  Herbert wished to accompany Cyrus Harding, but he would not vex Pencroft by his absence.

The next day, at dawn, Cyrus Harding and Ayrton, mounting the cart drawn by two onagers, took the road to the corral and set off at a round trot.

Above the forest were passing large clouds, to which the crater of Mount Franklin incessantly added fuliginous matter.  These clouds, which rolled heavily in the air, were evidently composed of heterogeneous substances.  It was not alone from the volcano that they derived their strange opacity and weight.  Scoriae, in a state of dust, like powdered pumice-stone, and grayish ashes as small as the finest feculae, were held in suspension in the midst of their thick folds.  These ashes are so fine that they have been observed in the air for whole months.  After the eruption of 1783 in Iceland for upwards of a year the atmosphere was thus charged with volcanic dust through which the rays of the sun were only with difficulty discernible.

But more often this pulverized matter falls, and this happened on the present occasion.  Cyrus Harding and Ayrton had scarcely reached the corral when a sort of black snow like fine gunpowder fell, and instantly changed the appearance of the soil.  Trees, meadows, all disappeared beneath a covering several inches in depth.  But, very fortunately, the wind blew from the northeast, and the greater part of the cloud dissolved itself over the sea.

“This is very singular, Captain Harding,” said Ayrton.

“It is very serious,” replied the engineer.  “This powdered pumice-stone, all this mineral dust, proves how grave is the convulsion going forward in the lower depths of the volcano.”