B chapter.indd - Charles Babbage Institute - University of Minnesota

154
Pagination: pp. 28
Collation: A–C 4 E 2
Size: 258x201 mm
Reference: Pogg Vol. I, p. 200; Gun AOW II, 319
See also the entry for Bird, John; The method of dividing
astronomical instruments, 1767, London.
This volume is the second half of Bird’s commitment to
produce a full description of how he created the 8-foot
mural quadrant. It is interesting in that Bird describes
not only the details of his successful construction of
the quadrant but also his failures (such as an attempt to
create the telescope without bracing).
Illustrations available:
Title page
B 168
Bird, John (1709–1776)
The method of dividing astronomical instruments.
Year: 1767
Place: London
Publisher: J. Nourse; and Mess. Mount and Page
Edition: 1st
Language: English
Figures: 1 large engraved folding plate
Binding: later paper wrappers
Pagination: pp. vi, 14
Collation: A–E 2
Size: 258x201 mm
John Bird was a major instrument maker in London.
He began his career as a weaver but soon developed a
part-time business helping watch face makers. He later
worked for an instrument maker named Graham before
opening his own instrument shop. He was commissioned
to construct a large (8-foot radius) mural quadrant at
the Royal Observatory at Greenwich (completed in
1749) when the earlier one done by Graham began to
deform under its own weight. The Commissioners of
Longitude (and, in particular, the Astronomer Royal,
Neville Maskelyne) were responsible for the quadrant’s
construction and wanted to ensure that the methods used
by Bird (then in business for some thirty-four years)
would be available to his successors. In return for a sum
of £500 (plus an additional £60 for engraved plates), Bird
agreed to take an apprentice and instruct him for seven
years and to present to the commissioners a full and
complete description of how the quadrant scales were
divided. This volume is the fulfillment of the written
part of that commitment. The quadrant had actually been
constructed seventeen years earlier, and one can presume
that the commissioners were anxious to have all the plans
and descriptions finished.
Erwin Tomash Library
Bird, John Birkhoff, Garrett
Great care was obviously taken with the division of the
scales. Bird describes how the brass quadrant scales and
the pine beam compasses were left in a locked room over
night so that they might stabilize to the same temperature.
He also sketches out a method of dividing a scale by
establishing a few elementary basic measurements and
then using repeated bisections to create the other marks.
The one diagram is marked Plate iv because it is the
fourth plate from his engraved plates of the quadrant (see
entry for Bird, John; The method of constructing mural
quadrants. Exemplified by a description of the brass
mural quadrant in the Royal Observatory at Greenwich,
1768, for the other three).
Illustrations available:
Title page
B 169
Birkhoff, Garrett (1911–); K. O. Friedrichs and T. E.
Sterne, editors
Transactions of the symposium on fluid mechanics and
computing held at New York University, April 23–24,
1953. The first symposium on applied mathematics
sponsored by the American Mathematical Society and
Office of Ordnance Research, U. S. Army
Year: 1954
Place: New York
Publisher: Interscience Publishers
B 168