JOHN BLISS & CO.'S
IMPROVED AZIMUTH INSTRUMENT
Designed to be used with "liquid compasses of standard sizes" to determine the bearing (azimuth) of objects at sea. Whatever compass was used had to be "prepared" by drilling an indentation in the very center of the glass to take the center pin. A swinging mirror (attached to the left side sight vane) allowed bearings of celestial objects, and a sliding eye shade on the right vane allowed bearings of the sun. Alternatively, sun bearings can be taken by lining up the shadow of the vertical thread with the line on the white section. Accurate sun bearings can be used to check compass variation at sea. For more details click on the catalog scan bottom right. Produced in 3 sizes which sold for $18.00, $20.00, or $22.00 in 1907. I don't know which size mine is, but overall length (vanes folded) is 7.5 inches, and the legs are 4.3 inches apart, requiring a compass face of at least 5 inches. This fits my No. 63 compass which has been "prepared" for this instrument.
Scans from the Bliss 1909 "Abridgment"
Text copyright Norman Bliss 2002. Photographs courtesy Captain
Page created 3/13/04.