DMM 38939

Museum: Deutsches Museum, Munich

Title: Sector by Michael Butterfield

Inventory number: DMM 38939

Signature: "Buterfield a paris." 

Date: Between 1635 - 1724

Material: Brass

Dimensions: Lenght of limb: 110 mm; width: 13 mm

Description: See Schneider, 1970, p. 88. 

Preliminary examination of the metallic scales: The front presents a metallic line with 6 values. Planetary symbols on the metal scale, indicated a "Les Metaux". Two other scales, each on a face, when the sector is opened at 180 degrees, on the border. Called respectively "poi des boulets" [sic] and "Calibre des pies" [sic]. 

ReferencesSchneider, Ivo: Der Proportionalzirkel: Ein universelles Analogrecheninstrument der Vergangenheit. Deutsches Museum: Abhandlungen und Berichte. 38. Jahrgang 1970, Heft 2. München, Düsseldorf 1970, p. 88.

Maurice, Daumas: Les instruments scientifiques aux XVIIe et XVIIIe siecle. Paris, 1953, p. 107f.

Measurements of Scales (in mm)

"Les Metaux"

☉ [Sun, Gold]

79

♄ [Saturn, Lead]

93

☽ [Moon, Silver]

97

♀ [Venus, Copper]

101,5

♀ [repeats the Venus symbol,

but it is iron]

105

♃ [Jupiter, Tin]

108

"Calibre des pies"

1/4 34
1/2 41
3/4 47
1 51
2 65
4 81,5
6 93
8 103
10 110
15 116
20 128
25 138
30 147
35 153
40 164
45 175
50 185,5
55 194
60 205

"poi des boulets"

Note: the first two points for 1/4 and 1/2 are poorly indicated. I assume that the line of the scale corresponds to the line of the fraction.

1/4 34
2 [1/2] 40
3/4 45
1 51
2 65
4 82
6 94,5
8 104
10 112
15 119
20 131,5
25 142
30 151
35 157
40 168
45 179
50 191
55 199
60 210