Preheat oven to 475 degrees F. Sift flour, cream of tartar, baking soda, and salt into a medium bowl. Cut in lard using a pastry blender. Add milk all at once and toss with fork. Knead 5 or 6 times on a lightly floured board, and roll or pat to a ½- or ¾-inch thickness. Cut with a biscuit cutter, and top each biscuit with a bit of butter. Place onto a greased cookie sheet and bake for 5 minutes. Turn off heat and leave in the oven for 5 to 10 minutes longer, until golden. Serve hot.