Tom,
William Jacob Witherall married Inez M. Knapp. William was the son of Rudolphus, who was son of Naphtali who was son of Jacob Witherell of Barre, Mass. See the following Wisconsin marriage record:
Not sure about your information or if you are refering to a different Witherall family. I don't have an Emma Knapp in my database nor have I heard of Runy Witherall. I can trace our Knapp family back to Colonial, but cannot find parentage of Julia Maria Lathrop. We have corresponded before. You should have my info. If not, check out my Ancestry tree http://trees.ancestry.com/tree/17758420/family?fpid=
David

Wisconsin Pre-1907 Marriage Record
Date of Registration: Oct 28, 1886
The Color of the Parties: White
Full Name of Husband: William Jacob Witherall
Name of the father of Husband: Rudolph Witherall
Name of the mother of husband before marriage: Sarah Witherall [maiden name Wray]
Occupation of Husband: Conductor
Residence of Husband: Grand Rapids
Birthplace of Husband: Fond du Lac
Full Name of Wife Previous to Marriage: Inez M. Knapp
Name of Father of Wife: Alfred Elias Knapp
Name of Mother of Wife before marriage: Julia Maria Knapp
Birthplace of wife: Not given
Place Where the Marriage was Contracted: New London, Wisconsin
Time When the Marriage was Contracted: Oct 19, 1886
By What Ceremony Contracted: Religious
Name of Person Pronouncing Marriage: William Blackwell
Residence of Person Last Named: New London, Wisconsin
Names of Subscribing Witnesses: Leo T. Edwards, Thos Fomfscoke??
Date of Certificate of Marriage: Oct 26, 1886