It was not until 1933 that another German missionary lived in Tanga again and worked together with Yakobo Ng´ombe. This pastor, Ernst Dammann, [34] later became a well known scholar in African Studies. He preserved some of Yakobo`s manuscripts and also published Safari ya Bukoba ("A Journey to Bukoba") [35], Yakobo Lumwe`s diary of a trip in 1930 to Buhaya, northwest Tanganyika.
Haikuwa kwamba hadi mwaka wa 1933, kuwa mmissionari mwingine mjerumani alirudi kuishi Tanga tena na kufanya kazi pamoja na Yakobo Ng`ombe. Huyu mchungaji, Ernst Dammann, [34] baadaye alifahamika vizuri kama mtaalamu katika Lugha za Kiafrika. Alihifadhi baadhi ya maandishi yaliyoandikwa kwa mkono ya Yakobo Ng'ombe na pia kuchapisha "Safari ya Bukoba" [35] kitabu cha Yakobo Lumwe cha kumbukumbu, safari ya Buhaya, Magharibi Tanganyika, katika mwaka wa 1930. Alichaguliwa pia kumsindikiza Kurt Ronicke wa Bethel-- Mission aliyekuwa mwangalizi mkuu wakati ule, kwa safari ya kutembelea.