Who is Sandy Murry from Many Waters and what is their importance?

Sandy is one of the identical twins. He wants to become a lawyer and has no interest in science. Sandy has, however, picked up enough scientific knowledge from his family to understand what might be happening to himself and his brother in this strange new land. He's the one who figures out how to use a quantum leap in order to get back to their time. Over the course of the novel, Sandy becomes very ill from the sun, after which, he recovers in the tent of Lamech. He is close to his twin brother and misses him when they are separated. Sandy is fifteen years old and has a crush on Yalith. This startles him because he has never felt so strongly attracted to a female before. He asks the girl if she would like to go back to his time with him.