Discusses changes in the crystal structure of iron and steel when these materials are heated. Focuses on observations related to an experiment in which a 60-inch length of piano wire (No. 29 steel wire) is heated and then cooled. (JN)

Relates how Charles Martin Hall discovered the method of making pure aluminum metal in 1886. Retraces the events and steps that led to the process of aluminum purification. Includes diagrams of the apparatus used in the investigations. (ML)

Describes a method to detect the presence of microgram quantities of nearly any metal in samples of alloys, minerals, water, and air. This chemical-spot testing technique requires no elaborate equipment and can be done by an amateur. (SK)