We tarried in the foul and blackening emanations from the marsh because we had agreed to receive on board about thirty poor orphan boys and girls, and a few helpless widows whom Bishop Mackenzie had attached to his Mission.  All who were able to support themselves had been encouraged by the Missionaries to do so by cultivating the ground, and they now formed a little free community.  But the boys and girls who were only from seven to twelve years of age, and orphans without any one to help them, could not be abandoned without bringing odium on the English name.  The effect of an outcry by some persons in England, who knew nothing of the circumstances in which Bishop Mackenzie was placed, and who certainly had not given up their own right of appeal to the sword of the magistrate, was, that the new head of the Mission had gone to extremes in the opposite direction from his predecessor; not even protesting against the one monstrous evil of the country, the slave-trade.  We believed that we ought to leave the English name in the same good repute among the natives that we had found it; and in removing the poor creatures, who had lived with Mackenzie as children with a father, to a land where the education he began would be completed, we had the aid and sympathy of the best of the Portuguese, and of the whole population.  The difference between shipping slaves and receiving these free orphans struck us as they came on board.  As soon as permission to embark was given, the rush into the boat nearly swamped her—­their eagerness to be safe on the “Pioneer’s” deck had to be repressed.

Bishop Tozer had already left for Quillimane when we took these people and the last of the Universities’ Missionaries on board and proceeded to the Zambesi.  It was in high flood.  We have always spoken of this river as if at its lowest, for fear lest we should convey an exaggerated impression of its capabilities for navigation.  Instead of from five to fifteen feet, it was now from fifteen to thirty feet, or more, deep.  All the sandbanks and many of the islands had disappeared, and before us rolled a river capable, as one of our naval friends thought, of carrying a gunboat.  Some of the sandy islands are annually swept away, and the quantities of sand carried down are prodigious.

The process by which a delta, extending eighty or one hundred miles from the sea, has been formed may be seen going on at the present day—­the coarser particles of sand are driven out into the ocean, just in the same way as we see they are over banks in the beds of torrents.  The finer portions are caught by the returning tide, and, accumulating by successive ebbs and flows, become, with the decaying vegetation, arrested by the mangrove roots.  The influence of the tide in bringing back the finer particles gives the sea near the mouth of the Zambesi a clean and sandy bottom.  This process has been going on for ages, and as the delta has enlarged eastwards, the river has always kept a channel for itself behind.