The spell was of little use. Albus deduced that the street side of Sirius’s Fidelius on his house was sixty feet wide and, since the other townhouses were four stories tall, the height of the street side of Sirius’s Fidelius had to be forty-eight feet tall (plus the height of the roof). But the spell that Albus had just cast told him only Here is where a part, which measures twelve feet by ten feet, is of one side of the Fidelius.