— born in Indiana, probably in Evansville, Vanderburgh Co., IN:
7.  Elizabeth STRAUB, b. 1854/5; d.s.p. bef. 1870

1a.  Anon.  1966.  Marriage Index:  Ohio, 1789-1850.  Liahona Research, Orem, UT (Broderbund CD-400):  not found.

1b.  Indiana Works Progress Administration.  1939.  Index to Marriage Records, Vanderburgh County, Indiana, 1846-1920 (online at GenealogyLibrary.com):
Based on this source, there are no marriages for Mathilda or Elizabeth.

2.  1840 Census:  won't start looking for him in 1840 until I've found him in 1850.

3.  1850 Census:  still looking.

4.  1860 Census Images (online at Ancestry.com; Image #75 of 526):  Evansville P.O., City of Evansville, Pigeon Twp., Vanderburgh Co., IN, p. 473, PN 75, enumerated 20 Aug 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):¤•

1860:  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	12
568	573	Charles Greepke	20	M		Tinner			Prussia
		John Edwards	24	M		do			Eng
		Jacob Straub	52	M		Finisher?	4000	2000	Ga-Hessia Drstdt
		Regina	47	F					Bavaria
569		Friedr	24	M		Hd W. Merchant			O
		Charlotte	19	F					"
		Mathilda	17	F					"
		Louis	15	M					"
		Henry	13	M					"	/
		Emilia	10	F					"	/
		Elizabeth	5	F					Ind	/

The family and dwelling numbers make no sense.  Charles GREEPKE and John EDWARDS could hardly be members of Jacob's family, and it's absurb that Jacob's children would be living in a separate domicile.  This census-enumerator appeares to have misunderstood the intended meaning of dwelling and family numbers because, throughout his enumeration, his use of them is simply bizarre.  I think the dwelling and family numbers are best ignored, along with Mr. GREEPKE and Mr. EDWARDS.  I was barely able to decipher Jacob's occupation, so I may not have it right, but it definitely was not "Tinner."

5.  1870 Census Images (online at Ancestry.com; Image #383 of 851):  Evansville P.O., Evansville (Ward 5), Vanderburgh Co., IN, p. 280A, PN 51, enumerated 12 Aug 1870 (extracted by Diana Gale Matthiesen):¤•

1870:  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

19

411

404

Straub Jacob

62

M

W

Retl? Merchant

5000

12000

H Darmstadt

/

/

/

______ Regina

57

F

W

K H

Bavaria

/

/

______ Charlotte

30

F

W

Ohio

/

/

______ Epest??ia?

22

F

W

Do

/

/

______ Leroy?

27

M

W

Ret Hardware

3000

Do

/

/

/

______ Henry E

24

M

W

Clk    Do

Do

/

/

/

Good grief.  Charlotte and Henry are OK, and Leroy(?) has to be Louis.  But how in the world did the enumerator turn Amelia into… whatever that name is?

6.  1880 Census Images (online at Ancestry.com; Image #24-25 of 39):  5 Clark Street, Evansville, Vanderburgh Co., IN, Roll 317 (Book 1), pp. 380B-381A, PN 24-25, SD 1, ED 83, enumerated 7 Jun 1880 (extracted by Diana Gale Matthiesen):¤•

1880:  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	8	9	10	24	25	26
198	242	Straub, Jacob	W	M	72			/	Hesse Darmstadt	H Darmstadt	Bavaria
		_______ Racheal	W	F	67	Wife		/	Bavaria	Bavaria	Bavaria
[next page]
198	242	Straub, Amelia	W	F	29	Daughter	/		Ohio	H Darmstadt	Bavaria

Jacob's wife is obviously still the same woman, so it's hard to figure the name change.  Is it enumerator error?