Raising the bar for those who followed: Henry Rowland and the solar spectrum

HIST 18

Steven C. Turner, Division of Medicine and Science, Smithsonian Institution, mrc 627, P.O. Box 37012, Washington, DC 20013-7012
No consideration of twentieth century spectroscopy can be complete without recognizing the contributions of Henry Augustus Rowland. In particular, his Photographic Map of the Normal Solar Spectrum, 1888, and Preliminary Table of Solar Spectrum Wave-Lengths, 1898, provided the foundations on which future developments in spectroscopy would be built.

Like any true landmarks, these works are important on a number of historic levels. In their most obvious role, as laboratory standards, they represented a new level of precision measurement and created a global demand for diffraction gratings made on Rowland's machines. Yet Rowland's successes also inspired efforts to exceed him and pushed American spectroscopy to new levels of precision.

Ultimately we can gauge Rowland's importance by the fact that contemporary wavelength tables continue to be called “revisions” or “extensions” of his work.