Boil potatoes whole until done (when peels come away a bit). Mix soup cans with the milk to thin and set aside. When potatoes are cool enough to handle, gently remove peels and make a layer of sliced potatoes in 9x13 pan (they should overlap slightly). Spoon 1/3 of the soup mixture over potatoes. Dot with pats of butter. Then layer with slices of cheese. Repeat process, making 3 layers. Bake in oven at 350(covered with foil) about 45 minutes. Remove foil and bake another 15 minutes, just to make the top layer of cheese a bit brown and bubbly.