Accession No
6065
Brief Description
Fineman’s Mirror Nephoscope, by Philibert and Felix Pellin, French, 1900 (c)
Origin
France; Paris
Maker
Pellin, Philibert and Felix
Class
meteorology
Earliest Date
1886
Latest Date
1902
Inscription Date
Material
metal (brass); glass; wood (boxwood)
Dimensions
triangular base 204mm x 204mm; height to black glass 136mm
Special Collection
Provenance
Purchased from Tesseract, Box 151, Hastings-on-Hudson, New York 10706, U.S.A., on or before 17/02/2006. Tesseract catalogue 81 Winter 2005/2006.
Inscription
‘Ph & F Pellin, Paris’
Description Notes
Fineman’s nephoscope; French; by Pellin; c.1900
Three legged base (brass) with levelling screws, and tapered pillar supporting a 12cm diameter glazed compass. Edge carries compass bearings N,E,S,W divided to 45°. Fitting over the compass is a flat brass assembly with black glass top, boxwood handles, and edge-mounted sharp-pointed indicator adjustable in height (by rack-and-pinion) from 20mm to 100mm above the top, with readout to 1mm.
The black glass contains a small transparent circular window for viewing the end of the compass needle, and is etched with 3 concentric circles, divided into 8 segments.
Stamped “3” by boxwood handle (serial no.?).
Condition: good; complete
References
Allison Ksiazkiewicz; 'Cloud Studies'; Explore Whipple Collections online article; Whipple Museum of the History of Science; University of Cambridge: https://www.whipplemuseum.cam.ac.uk/explore-whipple-collections/meteorology/cloud-studies
Events
Description
The Mirror Nephoscope, to a design first published by C. G. Fineman in 1886, is used to measure the velocity and direction of movement of clouds, and thus provides information about the wind at altitude.
The user sets up the nephoscope so that they see the tip of the adjustable pointer at the centre of the black glass mirror, and then aligns a specific cloud feature with this tip. Speed and direction are then determined by observing the motion of the cloud image against the etched lines on the mirror, and knowing the actual height of the pointer above the mirror. By timing the cloud movement angular velocity can be calculated, while absolute velocity of the cloud can be determined if the cloud's altitude is known.
The direction of motion of the cloud can be found using the compass placed beneath the reflective surface.
The maker of this specific instrument was the famous French Pellin firm, run by Philibert Pellin and his son, Felix. This instrument was listed in Pellin’s descriptive catalogue of meteorological instruments of 1902.
03/12/2007
Created by: Joshua Nall on 03/12/2007
FM:46534
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