Diagram
Date
17th century
Creator
Unknown, Artist
Object type
Archive reference number
Manuscript page number
p3
Material
Dimensions
height (page): 232mm
width (page): 169mm
width (page): 169mm
Subject
Description
Figure in a letter from Jean Dominique Cassini, dated at Paris, to Henry Oldenburg. It accompanies a description of Cassini's method (in English) for observing the altitude of the Sun using the meridian line inscribed on the floor of the St Petronio Church in Bologna. Similar examples of meridian lines may be found in Florence and elsewhere (see Heilbron, The Sun in the Church (1999)).
There is a copy of this figure at LBO/28/316.
There is a copy of this figure at LBO/28/316.
Transcription
The method whereby Cassini observeth the altitud[e]s of the Sun in St Petronius his church in Bologna.
A is a verie smal[l] round hol[e] in a thin brasse plate in the top of the church, AB is a perpendicular lett fal[l] to the floor, of which the the 1/100 part is F fixed on the wall of the church being ther[e] in brasse subsdivyded in a 1000 equal parts; BE is the mieridian line parallel to the horizon divyded in parts equal to F, which meridian in the mid[d]le is of brasse and in both sides of iron for the more firmnes[s] and soliditie.
Transcribed by the Making Visible project
A is a verie smal[l] round hol[e] in a thin brasse plate in the top of the church, AB is a perpendicular lett fal[l] to the floor, of which the the 1/100 part is F fixed on the wall of the church being ther[e] in brasse subsdivyded in a 1000 equal parts; BE is the mieridian line parallel to the horizon divyded in parts equal to F, which meridian in the mid[d]le is of brasse and in both sides of iron for the more firmnes[s] and soliditie.
Transcribed by the Making Visible project
Object history
For Cassini's design of the famous meridian line in the Church of St Petronio, see J. L. Heilbron, The Sun in the Church: Cathedrals as Solar Observatories (Cambridge, MA: Harvard University Press, 1999), pp. 82-119.
J. D. Cassini, La Meridiana Del Tempio Di S. Petronio: Tirata, e preparata per le Osseruazioni Astronomiche l'Anno 1655 (Bologna 1695).
J. D. Cassini, La Meridiana Del Tempio Di S. Petronio: Tirata, e preparata per le Osseruazioni Astronomiche l'Anno 1655 (Bologna 1695).
Related fellows
Jean Dominique Cassini (1625 - 1712, Italian) , Astronomer, Astronomer
Henry Oldenburg (1612 - 1677, German) , Scientific correspondent
Henry Oldenburg (1612 - 1677, German) , Scientific correspondent
Associated place