After reading the story now think why in the fourth chapter Sir Henry's only one boot from a pair disappeared another boot from another pair disappeared and the previous one reappeared .Give the logic

Stapleton stole one of Sir Henry's boots from the hotel, in order to acquaint the hound with his scent. But when Stapleton discovered that the first boot was too new to carry any personal scent, he had to steal an older one. It was the robbery of this second boot that initially convinced Holmes that they were indeed dealing with a real hound.