The name is absent

Introductory Statement         47

Milky Way itself, or perhaps larger, and explored mainly
through photometry of the giant and supergiant stars, vari-
able and invariable, which are congregated into the hundred
known globular systems.

6. The Clouds of Magellan, almost a hundred thousand
light years distant, and yet the nearest of all external galaxies
and the most easily studied, whether photometrically, spec-
troscopically, astrometrically, or statistically.

7. The Supergalaxies, varying in distance from one mil-
lion to a hundred million light years and more, and in bright-
ness from naked-eye visibility to the ultimate of telescopic
faintness, composed of many unit galaxies, sometimes of
hundreds or even thousands—measured with increasing diffi-
culty as the distances increase and the light grows fainter.

8. The Metagalaxy, extending beyond the limits of the
greatest existing telescopic power, composed of millions of
individual and clustered galaxies, including also the Magel-
lanic Clouds, the globular clusters, our MilkyWay, and the
Local System. The faint external galaxies, which consti-
tute the body of the Metagalaxy, are investigated, in our ex-
plorations, for brightness, position, form, size, distance, and
velocity. It is in this extensive metagalactic realm that we
find some evidence of a literally expanding universe, as re-
markable as the expanding knowledge of the sidereal world.

To several members of the Observatory staff I am in-
debted for assistance in presenting this interim report on our
joint researches in galactic measurements and structure. The
details of our investigations are published principally in the
Bulletins, Circulars, and Annals of the Harvard Observa-
tory.

April 15, 1931

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