Sift flour, salt, baking soda, cream of tartar and baking powder. Cut in the butter with two knives until the mixture resembles coarse crumbs. Add the milk and stir with a fork until the dough is mixed and pulls away from the sides of the bowl.
For drop biscuits, drop tablespoons of the dough onto buttered baking sheets.
For rolled biscuits, turn the dough onto a floured board and roll it into a sheet about 1 inch thick. Use a round cutter to cut out the biscuits. Do not handle the dough too much, for this will make the biscuits less tender.
For square biscuits, roll onto the dough and cut into squares, or par the dough into a buttered 9-inch-square pan or a rectangular pan 8 x 10 inches. Cut into squares when done.
Bake in a preheated 400 degree F. oven for 20 to 30 minutes, or until they are golden brown. Makes 16 to 24 biscuits.