High Standard Alidade
This alidade consists of straightedges with a rigidly-mounted telescope that can be rotated through the vertical angle ±30. The telescope is set on a high standard or post (4 inches in height) to raise it above the table. The telescope for the high standard is 16 power, inverting type with internal focusing. It is made of brass and was manufactured by Keuffel & Esser Company, New York & New Jersey.
Object ID: USGS-000158