Cream butter; gradually add 1 1/2 cups sugar, beating until light and fluffy. Add eggs, one at a time, beating well after each addition. Combine flour, cream of tartar, soda and salt; add to creamed mixture, beating until blended. Chill dough at least 1 hour.
Shape dough into 1-inch balls; roll in sugar. Place on lightly greased cookie sheets; bake at 400° 6 to 8 minutes or until lightly browned. Let cool on wire racks. Makes 5 dozen.