This is what is readable on the Headstone:
GEORGE W. KOHLER
CO. ( ? REAL) N. H. VOL.
DIED JULY 1, 1896
AGED 50 YEARS

Where the question mark is it looks like a I, O, or maybe a G and the word “REAL” is probably REGT. but has worn over the years. 

Let us never forget the soldier's sacrifice.