1.  LDS.  Family Search: Internet Genealogy Service: International Genealogical Index (IGI).

Martin HORN Spouse: Christina KEMMERER Marriage: 1 Jan 1833, Knox, Ohio Source: Marriage records, 1808-1912. Ohio. Probate Court (Knox County).

2.  Family Quest Archives:  Ohio Federal Census 1840:  Knox County.  Heritage Quest CD M704-406 (extracted by Diana Gale Matthiesen):

1840

OH

Knox Co.

Butler Twp.

p. 407B

Martin Horn ????

100 010 - 110 010

There is something written after his name, but I can't read it (doesn't really look like "Jr.").  These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	4 or under	1835-1840	= Christian (b. 1836/7)
1 male	20-29	1810-1820	= Martin (b. 1810)
1 female	4 or under	1835-1840	= Nancy (b. 1838/9)
1 female	5-9	1830-1835	= Mary (b. 1833)
1 female	20-29	1810-1820	= Christina (b. 1813)

3.  Family Quest Archives:  Ohio Federal Census 1850: Knox County.  Heritage Quest CD M432-700:  Butler Twp., Knox Co., OH, p. 395B, 2417/2477, enumerated 23 Sep 1850 (extracted by Diana Gale Matthiesen):

Martin S. Horn	39	M	Farmer	2000	Penn
Christina  "	37	F			Virginia
Mary       "	17	F			Ohio
Christian  "	13	M			"
Nancy      "	11	F			"
Julia A.   "	9	F			"
Noah       "	7	M			"
Peter      "	5	M			"
Hiram      "	3	M			"
Adam       "	11/12	M			"