Another name for Henry was Henry Leis.
The 1910 US Census for Henry's son, Casper Henry Leas indicateds that Casper immigrated to the USA from Germany in 1874. Casper would have been 9 years old, so it is quite likely that Henry and Agnes Katherine also imigrated to the USA in 1874.
1 Gordon Jim, to David Leas, e-mail, June 15, 2011, privately held by Leas.
2 Notes from David A. Leas and/or the 1950 Leas Family Genealogy.
Arthur Leas on http://genforum.genealogy.com/leas/messages/42.html.