I am trying to trace part of my family tree -  One of the Zimmermann brothers - sons of Sophie Zimmermann of East Prussia, came to East Africa  and I think he was an artist or possible a scientist as he went around drawing pictures of birds and/or plants.   Does anyone  know more about this man?  His brother would have been Herman Zimmermann  the missionary in the Northern Transvaal, South Africa.
Any help would be most welcome.