Accession No
2751
Brief Description
taffrail log, by John Bliss and Company, U.S.A., 1900 (c)
Origin
U.S.A.; New York
Maker
John Bliss and Company
Class
navigation
Earliest Date
1900
Latest Date
1900
Inscription Date
Material
metal (brass); enamel; glass; rope; wood
Dimensions
box length 500mm; breadth 195mm; height 108mm
Special Collection
Provenance
Purchased from Historical Technology Inc, Catalogue 121, Winter 1980, No 211.,1980.
Inscription
‘JOHN BLISS & CO.
TAFFRAIL
LOG NEW YORK U.S.A.’
‘BLISS. NEW YORK. U.S.A.’
‘BLISS TAFFRAIL LOG’
‘331’
‘BLISS Taffrail Log’ (on box)
Description Notes
Ships taffrail log. Brass register pivots in brass fork mount. Glazed white enamel register with 3 indexes. Length of rope with brass hook and rotor. Wooden box.
References
Events
Description
Log
A log is used to measure the speed of a ship relative to the surrounding water. Navigation can then be done using “dead reckoning”. The name “log” comes from the original method which involved throwing a log overboard so the relative speeds of the ship and log could be noted. However, by the 17th century, something more accurate was needed.
The first successful self recording log was patented in 1802. It consisted of a spiral moving along the direction of its length, and these revolutions turned a wheel. The speed of rotation of this wheel, and therefore the speed of the ship through water, could then be easily determined and recorded. The harpoon log followed this basic idea and was patented in 1861. The taffrail log did too, but it was easier to read off the dials in this case because, as the name suggests, they were put along the taffrail.
18/10/2002
Created by: Saffron Clackson on 18/10/2002
FM:44395
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