I have found who I beleive is your Jacob in the 1850 Pa. census in Upper Leacock Twp.,Lancaster Co.,Pa. It lists the following.
Jacob Rish 49
The only info on Jacob 1768 is He and his brother Peter were living in Northhampton Co in 1790 and both were married. Peter had a son that in the 1810 census there was a John living there. I found John in that Co. in 1850 age 64. However I have lost Jacob. He is not in that Co. in 1810. He could have went back to Lancaster Co. I'm still Looking