1.  Marriage Record:

2.  1850

3.  1860

4.  1870

5.  1880 Census Every-Name-Index/Images (online at Ancestry.com):  I can't find Thomas, not with any certainty and not in this census or any of the earlier ones.

6.  1890 Census:  the 1890 Census Population Schedules were destroyed.

7.  1900 Census Every-Name-Index/Images (online at Ancestry.com, Image #7 of 11 — indexed "James Jones"):  Hale Twp. (East Pct.), Hardin Co., OH, Roll T623_1284, p. 78A, SN 12, SD 7, ED 85, enumerated 15 Jun 1900, official enumeration date 1 Jun 1900 (extracted by Diana Gale Matthiesen):

1900:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).
1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	19	20	22	23	24	25	26	27	28
250	257	Iams Thomas	Head	W	M	Jun 1830	70	M	8			Penn	Pennsylvania	Pennsylvania	Farmer	0	Y	Y	Y	O	M	F	78
		____ Sarah J	Wife	W	F	Jul 1845	54	M	8	5	5	Ohio	York State	New York	Keeping House		Y	Y	Y
		Rumbough Effie	GDau	W	F	Dec 1893	6	S				Ohio	Ohio	Ohio			N	N	Y

Effie RUMBOUGH is the daughter of Sarah Jane and her second husband, James W. DOUGLAS (i.e., Effie is not Thomas's granddaughter).

8.  1910 Census Every-Name-Index/Images (online at Ancestry.com, Image #5 of 26):  Village of Forest, Jackson Twp., Hardin Co., OH, Roll T624_1187 (Book 2), p. 122A, SN 3A, SD 7, ED 106, enumerated 20 Apr 1910, official enumeration date 15 Apr 1910 (extracted by Diana Gale Matthiesen):

1910:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).
1	2	3	4	5	6	7	8	10	11	12	13	14	17	18	19	23	24	26	27	28
68	70	Iams Sarah J	Head	F	W	65	Wd	1	0	OH	NY	NY	Eng	Own Income		Y	Y	O	F	H
		Rumbaugh Effie	GDau	F	W	16	S			OH	OH	OH	Eng	None		Y	Y

9.  1920 Census Every-Name-Index/Images (online at Ancestry.com, Image #13 of 15):  1008 East Wayne St., Lima City (Ward 1), Ottawa Twp., Allen Co., OH, Roll, p. 59A, SN 7A, SD 3, ED 20, enumertaed 9 Jan 1920, official enumeration date 1 Jan 1920 (extracted by Diana Gale Matthiesen):

1920:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).
1	2	3	4	5	6	7	8	9	10	11	12	17	18	19	21	23	25	26
*	1008	154	154	Imes Sarah J	Widow	O	Un	F	W	75	Wd	Y	Y	OH	OH	OH	Y	None
*East Wayne St

10.  WorldConnect / Ancestry World Trees (online at RootsWeb.com/Ancestry.com).

11.  Messages posted to the Iams, Iiams, and Imes Family Genealogy Fora (online at GenForum.com)

12.  Messages posted to the IAMS and IIAMS Surname Boards (online at RootsWeb.com/Ancestry.com).