Necessity is not the mother of invention. Knowledge and experiment are its parents. It sometimes happens that successful search is made for unknown materials to fill well-recognized and predetermined requirements. It more often happens that the acquirement of knowledge of the previously unknown properties of a material suggests its trial for some new use. These facts strongly indicate the value of knowledge of properties of materials and indicate a way for research.
Blessed assurance, Jesus is mine! O what a foretaste of glory divine! Heir of salvation, purchase of God. Born of His Spirit, washed in His blood.