Signedunsigned
Inscribedlabel: Lead 2/25/25 D White.
FunctionThis is one of a group of bars in a box made so that they contain about one septillion atoms. As a consequence, all these bars will have the same heat capacity, that of about 6.1 gr. of water.
They may have been used by T. W. Richards to determine the exact atomic weight of the chemical (in this case lead).
It may also have been used to show that the heat capacity of a metal only depends on the number of atoms in the sample and not its composition. This would have been done with a calorimeter.
From Webster's 1913 unabridged: "Lead: 1. (Chem.) One of the elements, a heavy, pliable, inelastic metal, having a bright, bluish color, but easily tarnished. It is both malleable and ductile, though with little tenacity, and is used for tubes, sheets, bullets, etc. Its specific gravity is 11.37. It is easily fusible, forms alloys with other metals, and is an ingredient of solder and type metal. Atomic weight, 206.4. Symbol Pb It is chiefly obtained from the mineral galena, lead sulphide."
Historical Attributes
Belonged to Harvard Nobel Prize winner Theodore William Richards.