I found Peter and Matilda in 1910 I think. You didn't give dates of births so I am not sure. But he does work in an iron foundry as a foreman.
Pennsylvania > Philadelphia > Philadelphia Ward 29 > District 672 Martz, Peter,55, b Pa, fa b Germ, mo b Pa, foreman, iron foundry. Mathilda,54, b Pa, par b Pa mar 38 yrs, had 13 children,8 living Peter, 33, b Pa, no occupation
I found this birth, not sure who he is. Likely the son above. Reading, Pennsylvania Births, 1876-1905 Name: Peter Martz Birth Date: 13 Dec 1876 File Number: 693 Source: City of Reading, Pennsylvania Birth Records
Possibly his parents: 1870 United States Federal Census
Name: Peter Mertz Estimated birth year: abt 1856 Age in 1870: 14 Birthplace: Pennsylvania Home in 1870: Richmond, Berks, Pennsylvania Family and neighbors: View Results Race: White Gender: Male Value of real estate: View image Post Office: Kutztown