I just did some more looking through my records and thought I'd post a copy here from my family research work:
They were indeed living in Kansas..in around 1910 - 1915 - later I have a reference to them in Buhl, Twin Falls, Idaho from around 1920. (Where you found the Bible.)
Their first boy Clarence died at around 17 and I have no record of the second HARRY GUSTAVE BEHRHORST having children..he died in 1987...perhaps this is why the Bible was thus neglected...thankfully you found it!
However they did adopt two children: Leon Clifford and Rhonda Ranae. Where they are now is a mystery. They may have even not taken the Behrhorst name.
Here is the info text from my research work:
Descendants of Christina Friederika Maria Polack
Generation No. 1
1.CHRISTINA FRIEDERIKA MARIA7 POLACKwas born 22 Jan 1871, and died 11 Aug 1952.She married HENRY BEHRHORST1.He was born 06 May 1866, and died 06 Feb 1935.
Children of CHRISTINA POLACK and HENRY BEHRHORST are: i. CLARENCE BEHRHORST, b. 03 Dec 1910; d. 25 Oct 1927. ii. HARRY GUSTAVE BEHRHORST, b. 22 Jan 19142; d. 19 Oct 1987, Buhl, Twin Falls, Idaho, United States of America2; m. MILDRED VOORHECS, 1947.
More About HARRY GUSTAVE BEHRHORST: Residence: 1930, Buhl, Twin Falls, Idaho3 Social Security Number: 518-18-10634 SSN issued: Idaho4