”TERTIARY STANDARDS WITH THE PLANE GRATING1
THE TESTING AND SELECTION OF STANDARDS
FIRST PAPER
By CHARLES E. ST. JOHN And L. W. WARE

INTRODUCTION

At the meeting, on Mount Wilson August-September 1910, of the International Union for Co-operation in Solar Research, the question arose as to the adaptability of the plane-grating spectrograph of long focus to interpolating between the secondary standards in the determinations of the standards of the third order, and in the measurement of arc, spark, and solar spectra in the international units. …”

Reference Data:

The Astrophysical Journal, Vol. 36, by American Astronomical Society, University of Chicago, 1912, page 14