However assuming William did not stay long on Zanzibar after his brother's departure, due to ill health, I believe these are views of Zanzibar from about 1870.
Mbali na hayo, tukichukulia kuwa William hakukaa sana Zanzibar baada ya kuondoka kwa ndugu yake kutokana na afya mbaya, basi naamini hizi ni mandhari za Zanzibar kuanzia takribani mwaka 1870.