Download Galileo Studies: Personality, Tradition, and Revolution PDF

TitleGalileo Studies: Personality, Tradition, and Revolution
LanguageEnglish
File Size5.5 MB
Total Pages148
Document Text Contents
Page 1

Personality, Tradition, and Revolution

Stillman Drake

aAnn zArbor

The University of M ichigan Press

Page 2

Copyright © by The University of Michigan 1970
All rights reserved

ISBN 0-472-08283-3
Library of Congress Catalog Card No. 73-124427

Published in the United States of America by

The University of Michigan Press and simultaneously
in Don Mills, Canada, by Longmans Canada Limited

Manufactured in the United States of America

To Bernard Cohen and Marshall Clagett

— who encourage even dissenters—

this book is affectionately dedicated

Page 74

7

G alileo and the Telescop,e

Wide differences of opinion have been— and are— expressed about

Galileo’s role in the invention, development, and astronomical use

of the telescope. Some of the issues perennially raised are illusory,

as when he is reproached for having claimed the original invention

of the instrument, a claim he never made. Others are genuine

problems, capable of more precise solutions than they are generally

given; for example, the chronology of Galileo’s first involvement

with the instrument. Still other issues must remain in the area of

probability and conjecture; among these is the question of the

extent of Galileo’s knowledge of the optical principles involved

in the construction of his telescopes. The present essay is con­

cerned principally with the order of events in Galileo’s early work

with the telescope, though some light may be shed on other issues

in the course of that discussion.

Galileo’s first published account of his own connection with

the telescope, given in March 1610, ran as follows:

About ten months ago a report reached my ears that a
certain Fleming had constructed a spyglass by means of which
visible objects, though very distant from the eye of the observer,
were distinctly seen as if nearby. Of this truly remarkable effect
several experiences were related, to which some persons gave
credence while others denied them. A few days later the report
was confirmed to me in a letter from a noble Frenchman at
Paris, Jacques Badovere, which caused me to apply myself
wholeheartedly to inquire into the means by which I might
arrive at the invention of a similar instrument. This I did
shortly afterwards, my basis being the theory of refraction.
First I prepared a tube of lead, at the ends of which I fitted
two glass lenses, both plane on one side while on the other

140

Galileo and the Telescope 141

side one was spherically concave and the other convex. Then,
placing my eye near the concave lens, I perceived objects satis­
factorily large and near, for they appeared three times closer
and nine times larger than when seen with the naked eye alone.
Next I constructed another one, more accurate, which repre­
sented objects as enlarged more than sixty times [that is, of
about eight power, equivalent in magnification to the usual

field glass of today].1
It was this instrument that he presented to the Venetian govern­

ment late in August 1609.
Galileo made no claim to the original discovery, but only to

its independent duplication and subsequent improvement, in this

first printed narrative. In his letter of presentation to the Venetian

government, however, he spoke of his instrument as having been

developed by reflection on the principles of perspective, without

mentioning the work of others. That statement is often portrayed

as a false representation and deserves comment in passing.

It was impossible for Galileo to pretend successfully to the

Venetian government, late in August 1609, that the telescope as

such was his own invention. This is so evident from existing

documents that it would scarcely be worth mentioning, were that

preposterous idea not frequently put forth as a part of the evidence

against Galileo’s integrity and honesty. Numerous letters of the

period show not only that word of the Dutch invention had reached

Italy by the first of August 1609, but that an unidentified person

visited Padua in July with a telescope in his possession, and then

traveled on to Venice in the hope of selling it.2 The Venetian

government referred the matter to Fra Paolo Sarpi for his opinion,

and on his recommendation the offer was refused. A ll this was

known to Galileo, whose instrument was accepted by the same

government a short time afterward. In addressing them, he claimed

only that his own instrument had been devised on optical principles,

and this was quite consistent with what he wrote and published

elsewhere, though his terminology varied.

The change from the word "perspective” in the letter of

presentation to the word "refraction” in the Starry Messenger to

identify the optical basis of his telescope has given rise to doubts

about Galileo’s own knowledge of the theoretical principles in­

volved. Such doubts are in part created by misunderstanding of the

Page 75

142 G A L I L E O S T U D I E S

sense of the word "perspective” at the time. The name "perspective

glasses” had been applied in England for at least thirty years to

single lenses or concave mirrors capable of enlarging the images

of distant objects. The word "perspective” was the standard Latin

synonym for the Greek "optics” in the nomenclature of mathe­

matical sciences during the Middle Ages and throughout the six­

teenth century. Tartaglia, in his preface to Euclid, included under

"Perspective Science” the works of both W itelo and Albrecht

Diirer, whereas we should be inclined to speak of W itelo’s optics

and Diirer’s perspective. Hence there exists no suitable basis in

the words alone for concluding that Galileo was either ignorant or

was bluffing. His knowledge of perspective was at least equal to

that of the ordinary professor of mathematics in any Italian uni­

versity of the time, and his knowledge of refraction equaled that

of any other professor of astronomy. In order to move from a

three-power to an eight-power instrument in a very short time— a

move that Dutch and French makers had not made in several

months— Galileo probably did apply his knowledge of optics. If

he did not, he certainly had extraordinary luck in improving the

instrument to eight power, to say nothing of incredible luck about

the end of the year in moving on to a thirty-power telescope,

which he applied to the heavens. Others were still unable to

produce an equivalent instrument for a very long time afterward.

Jacques Badovere had been a pupil of Galileo’s at Padua,

residing in his house in 1598. He was a frequent visitor from

France. In 1607 he provided an affidavit, for use in legal pro­

ceedings, concerning the manufacture of the proportional compass

by Galileo. But no correspondence between Galileo and Badovere

is known to exist. Badovere (more properly Badoer) was the son

of a rich Venetian merchant who had been converted to Protes­

tantism and migrated to France. Jacques returned to the Catholic

faith and became closely associated with the French Jesuits, for

whom he undertook various risky enterprises. For a time he held

a diplomatic post with the French government, abruptly terminated

by vigorous opposition from Sully and other important ministers.

Scandalous rumors were circulated against him, but he remains a

shadowy figure. If he ever wrote to Galileo about the telescope,

or anything else, the letter is lost. Yet one would expect Galileo

to have kept such a letter if he had received it, particularly in view

of his having referred to it in print.

The Fleming referred to by Galileo was Hans Lipperhey

(originally the family name was La Prey), who had obtained a

patent from Count Maurice of Nassau for his invention. Fra Paolo

Sarpi, who was appointed to report on the foreigner’s instrument

to the Venetian government and was the pivotal figure in its re­

jection, had been the first man in Italy to learn of the Flemish

invention. His information came from Francesco Castrino in

November of 1608, only a month after Lipperhey applied for the

patent. In a letter to Castrino dated 9 December 1608, Sarpi

acknowledged receiving "a month ago” a report of the embassy

of the king of Siara to Count Maurice and news of the new

"spectacles.”3 Writing to Jerome Groslot de L’Isle on 6 January

1609, Sarpi said:

I have had word of the new spectacles more than a month,
and believe it sufficiently not to seek further, Socrates forbid­
ding us to philosophize about experiences not seen by ourselves.
When I was young I thought of such a thing, and it occurred
to me that a glass parabolically shaped could produce such an
effect. I had a demonstration, but since these are abstract matters
and do not take into account the fractiousness of matter, I
sensed some difficulty. Hence I was not much inclined to the
labor, which would have been very tiresome, so I did not
confirm or refute my idea by experiment. I do not know whether
perhaps that [Flemish] artisan has hit upon my idea— if indeed
that matter has not been swelled by report, as usual, in the

course of its journeys.4

Probably a similar account of Sarpi’s own speculations had

been sent to Badovere, with whom Sarpi (unlike Galileo) was

definitely in correspondence at this time. Sarpi maintained an

extensive correspondence with foreigners, Protestant and Catholic

alike, concerning every kind of political and religious develop­

ment in Europe and every important item of news. On 30 March

1609 he wrote to Badovere:

. . . I have given you my opinion of the Holland spec­
tacles. There may be something further; if you know more
about them, I should like to learn what is thought there. I have

Galileo and the Telescope 143

Page 147

286 G A L I L E O S T U D I E S

Olschki, Leonardo (1885—19 6 1),

64, 66, 72, 74, 76, 116

one-to-one correspondence, 225,
229, 234-35

orderly universe, 271—72, 275—76

Oresme, Nicole (1320—1382), 95,
237

Orlando, 169
Orsini, Alessandro Cardinal

(15 9 3 -16 2 6 ), 200
Oxford University, 95

Padua, 86, 111, 123-26, 141,

144-45, 148, 152-53, i74n,
181, 202; University of, 31, 33,

76, 87—89, 95, 100, i22n, 126,
131, 150, 214, 250, 262

Palisca, Claude, 62n

Palmerini, Thomas (d. 1625),
170-71

Papazzoni, Flaminio (1550?—

16 14 ), 161—62, 170—73, i74n,

i 75n
Pappus of Alexandria (fl. 285),

22, 32, 33, 35, 46

Paris, 40, 140, 178, 180, 185;
University of, 38, 95

Passignani, Domenico (1560—

1638), 189, i98n
Paul V (1552—16 2 1), 80, 88, 147

Pavia, 28

pendulum, 58, 70, 109, 2 15 -16
Peripatetics, 67, 90, 91, 114, 161—

65, 170, I74n, 179-80, 236,
245, 276; tradition of, 21, 24—

26, 28, 31, 35-39
Persio, Antonio (1542—16 12 ),

88-89
perspective, 141—42, 147, 149;

glasses, 142
Perugia, University of, 84
Pesaro, 33

Philoponus, Johannes (fl. 525?),
38, 95, 242

philosophy: and history, 2, 6—7,

19—20, 41, 231-32, 246, 266;

and physics, 6, 9, 13, 36, 39,
61, 63, 68, 72, 76—78, 101,

n o —11, 241-46, 253, 255, 265;
and mathematics, n o —11, 168;
of motion, 36—41, 221—23,
242-47

physics: pre-Galilean, 5—6, 68;

separate discipline, 13, 63, 68,
i n ; and mathematics, 23—24,

68-69, 97-98, 100—106, 109-
12, 114, 116, 12m , 168, 236-

37, 241—42, 276; and astron­

omy, 97-98, 113—20; see also
philosophy

Piccolomini, Eneas (fl. 16 10 ), 153

Pifferi, Francesco (fl. 1605), 90

Pignoria, Lorenzo (15 7 1—16 3 1),
146, 148

Pinelli, Giovanni Vincenzio

(t5 3 5 —16 0 1), 130
Pisa, 137, 170, 172, 261-62;

University of, 57, 72, 88, 100,
i n , 159, 161, 171, 220

plagiarism, 19, 28, 30, 127—29,

137, 180—182, 187, 188, 190,
224

planets: motion of, 126, 240, 253,

271—72, 275—76; circular orbits
of, 109, 254, 272-73, 277;

atmosphere of, 114; elliptical

orbits of, 254; and Platonic

solids, 128

Plato (427-347 B.C.), 6, 38, 83, 97

Platonic concepts, 61, 128, 272,

273

Platonism, 3, 7—8, 13

Playfere, Thomas (156 1 ?—1609),

98
Porta, Giambattista [della]

(1535?—1615 ), 80, 83, 86-87,

91, 146, 156, 177

Prague, 85, 132—34

Prime Mover, 244

printing and science, 20, 25, 28,

36-37, 45, 80, 220

Index 287

Priuli, Antonio (15 4 8 -16 2 3 ),
150, 152

projectiles, 4, 24, 26, 28, 39, 76,
214, 241-42, 244, 248, 250,
252, 257, 260, 262, 263, 266—

67, 274
proportion: theory of, 29, 48, 100,

223; in music, 47, 48, 56, 59—

60; see also speed

Ptolemaic system, 180

Ptolemy (fl. 14 0 ) , 2, 27, 31, 52,
74, 93; Almagest of, 100

Pythagoras (fl. 550 B.C.): and
musical theory, 48-49, 53, 57;

theorem of, 241

Ramee, Pierre de la (Ramus)

( 1 5 1 5 - 1 5 7 2 ) , 9- i 1
refraction, 87, 140, 147, i58n

Renaissance: science in, 20, 24—41

passim, 44-47, 95. 96, 98;
music in, 52—61 passim

resistance, 25, 26, 36, 112, 244,
246, 250, 2 55n; of medium, 26,
30, 168; of water to division,

165, 168; to motion, 25, 106,

113, 244, 249, 274
Ricci, Ostilio ( i 550 ?-i 620? ), 35

Richelieu, Armand Cardinal

(15 8 5 -16 4 2 ), 178-79
Roffeni, Giovanni Antonio

( i 58o? - i 643), 161, I74n
Rome, 30, 31, 79, 84-88, 91- 94.

127, 146, 147, 159. 160, 162,
172, 184, 185, 187, 188

Rore, Cipriano da (15 16 —156 5),

54
Rosen, Edward, 124—25, i39n,

149
Rudolf II (Holy Roman Emperor)

(15 5 2 -1 6 1 2 ) , 85, n o , 130,

134, 138

Sacrobosco (Holywood), Joannes
(13th c.), Sphere of, 90, 99—

100

Sagredo, Giovanni Francesco

(15 7 1-16 2 0 ), 130-31, I 97n,
204; as interlocutor, 40, 60,

232-34, 236
Salusbury, Thomas (d. 1666), 231
Salviati, Filippo (15 8 2 -16 14 ),

159, 162, 167, 177, 181, I97ni
as interlocutor, 40, 181, 232-34,

236, 271
Sapienza (College), 90
Sarpi, Paolo (15 5 2 -16 2 3 ), 109,

129, 141, 143—44, 146, 147-48,

201-4, 216—17, 219, 222, 227

Saturn, 82, 91
Scheiner, Christopher ( 1 5 7 5 -

1650), 91, 92, 115, 180-96

passim, i97n
Schreck, Johann (15 7 6 -16 3 0 ), 88,

89
science of weights, 22—23, 27—28,

32- 33, 95
scientific method, 9 -1 1 , 66—67, 93,

98, 118, 120
scientific revolution, 1, 19, 64, 66,

95-96, 121, 240, 244-45

secondary qualities, 61
Seggeth, Thomas (fl. 16 10 ), 132,

134
Seleucus (fl. 150 B.C.), 21 in
semicircular fall, 257-60, 268—70

senario, 53—55
sensory criteria, 48, 52—53, 56,

59-61, 74, 155, 167
Settle, Thomas, 2 38n
shapes, perfection of, 114, 243-44,

253—54, 265, 271, 276; of
floating bodies, 159-60, 164-67,

i 73n
ship: motion of, 251; motion with

respect to, 252, 268—69, 274

Siara, 143, I57n
Siena, 85; University of, 90
Simplicio (interlocutor), 40, 232—

34, 236
Simplicius (6th c.), 18
Sirturi, Girolamo (d. 16 3 1), I58n

Page 148

288 G A L I L E O S T U D I E S

Sizzi, Francesco ( 1585?—1 6 1 8 ) ,

91, 177-8 0 , 191, i9 7 n

Soccorsi, Filippo (d. 19 6 2 ? ) , 191

Socrates (4 70 ? -3 9 9 B.C.), 143
Soto, Domingo de ( 1 4 9 4 - 1 5 6 0 ) ,

38, 40, 216, 218, 236, 237

Spain, 38—40 passim

specific gravity, 28, 168 -69

speed, 2 1—22, 106, 215, 247; aver­

age, 230, 237; and power, 21;
and shape, 166; and weight,

29, 112, 215, 226; on inclined

plane, 73, 107, 215, 225, 250;
proportionality to time, 5,
38-41, 214, 216, 221, 223,

228—29, 232—38; proportionality
to space, 5, 38-41, 2 16 -17 ,
222—37; see also mean speed;

virtual velocities
statics, 27, 31, 34, 40, 101, 107,

112, 113; see also balance;
dynamics; equilibrium; motion

steelyard; see balance
Stelluti, Francesco (157 7—1646),

82-83, 87

Stevin, Simon (154 8 -16 2 0 ), 9,
30, 34, 50-52, 56, 102, 12m ;

on inclined plane, 103—4, 106
Strauss, Emil (d. 18 9 1), 181—84,

186, 190, I97n, I98n, 200, 205
strength of materials, 113
Strozzi, Giovanni Battista (15 5 1—

1634), 159, I75n
Sully, Maximilien (15 6 0 -16 4 1),

142
sun: rotation of, 115—16, 251;

tilted axis of, 120, 180,
182-96 passim, i98n;
incorruptibility of, 115

sunspots, 74, 75, 91, 92, 114, 115,

118, 120—21, 180—96
Swineshead, Richard (14th c.), 36

Tabaroni, Giorgio, 134, 136

Taisnier, Johannes (1509—1570?),

30

Tarde, Jean (15 6 1—1636), 190

Tartaglia, Niccolo (1500—15 5 7),

26-28, 31, 32, 35, 4m ,
46—47, 142, 236

technology, 22, 25, 68
telescope, 67, 76, 86—88, 90, 109,

114, 137, 140-57, 227; "Kep-
lerian,” 147, 155—56; reflecting,

156
Telesio, Bernardino (1509—1588),

245
Tengnagel, Francis (d. 1622), 85,

130-31, 138

Tenneur, Jacob Alexandre
(fl. 1650), 235-36

terminus ad quern, 223

Themistius (3 17 -3 8 7 ), 38
Thomaz, Alvarez (fl. 1510 ), 38

tides, 75, 118 -19 , 184, 194, 200-
2 11; model of, 206, 2i2n

times-squared rule, 109, 217—18,
222, 224, 227—28, 240

Torricelli, Evangelista (160 8-

1647), 13
translators, 222, 229-32
Turin, 30, 85

Twain, Mark (18 3 5 -19 10 ), 243
Tycho; see Brahe, Tycho
Tyrrhenian Sea, 119

universities: and music, 9; and

science, 24-25, 35-37, 63,

71—72, 76, 87, 89-90, ioo- i o i ,
109, n o , 112, i22n, 175, 220;

see also Bologna; Ferrara;

Oxford; Padua; Paris; Pisa;
Perugia

Urban VIII ; see Barberini, Maffeo
Urbino, 31

vacuum, 28, 242
Valerio, Luca (1552—1618 ), 90,

93, 109, 224-27 passim
Varro, Michael (fl. 158 5), 220
Venice, 26, 29, 38, 39, 86, 87,

126, 133, 141, 144-46, 148,

Index

152—53, 202, 216; tides at, 204,
209; government of, 76, 87,

141, 146, 147, 149-57 passim

Venus, 69, 70, 74, 9 U 120
Verona, 26
Vesalius, Andreas (15 x 4 -15 6 4 ),

27
Vicomercati, Francesco (fl. 1550),

38
Vieta, Francois (154 0 -16 0 3 ), 178

Vinci, Leonardo da (14 5 2 -15 19 ),

6, 19, 28
virtual displacement, 24, 106,

112

virtual velocities, 24, 35, 112

Vitruvius (fl. 50 B.C.), 22
Viviani, Vincenzio (1622—1703),

Wackhenfels, Wackher von (fl.
16 10 ), 133, 134

Wallace, William, 38—39
Wallis, John (16 16 —1703), 204
Welser, Mark (1558—16 14 ), 90,

91, 115, 133-34, 181, I98n
Weston, Thomas (d. 1728?), 231
Witelo (1225?—1275? ), 142
Wohlwill, Emil (1835—1912), 205

Zabarella, Giacomo (1533—1589),

9 -11
Zachariason, Johannes ( 1 6 1 1 —

1656?), 155-56
Zarlino, Gioseffo (1 5 1 7 —1590),

43, 52-56
Zimara, Marcantonio (1460—

1532), 38

289

roo

Similer Documents