
Gene G. answered 06/04/19
You can do it! I'll show you how.
You can type the umlaut characters directly. You've found the codes for them, so you have what you need. Entry format: while holding the <alt> key, type the 4-digit code. You need a leading zero.
ä = Depress and hold <alt>0228
This is a Windows functionality, so it works pretty much anywhere.
(...) bemerkte ich (...) eine mir auffällige Übereinstimmung bezüglich des Inhaltes der drei Zeitungsfetzen: sie enthielten nämlich alle drei einen Bericht über die Ermordung eines reichen französischen Kaufmannes in Blidah.
... namely [that] all three included a report of a rich French merchant's murder in Blidah.
Both "reichen" and "and "französischen" are adjectives modifying the genitive masculine Kaufmannes. They do not adopt the genitive case; they only agree with his gender.