Public domain
Senator E.F. Ladd, of North Dakota, and W.G. Campbell, chief of the Bureau of Chemistry, in a laboratory
From the collection of Library of Congress. Free to download, adapt and use — no permission needed.
Credit lineSenator E.F. Ladd, of North Dakota, and W.G. Campbell, chief of the Bureau of Chemistry, in a laboratory. 1923-01-01. National Photo Company Collection, Library of Congress. Public domain.
