A recording hygrometer.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
an instrument for continuously recording the relative humidity of the air. The sensitive element of a hygrograph is a bundle of degreased human hair or organic film (see HYGROMETER). Recording is done on a calibrated ribbon mounted on a drum, which is rotated by a clock mechanism. The drum on a hygrograph may rotate once a day or once a week.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
A self-recording instrument that provides a continuous record of relative humidity on a drum-mounted chart known as a hygrogram
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved