Galileo Galilei and the Roman Curia/Chapter 22

by Karl von Gebler

CHAPTER II.

FAILING HEALTH AND LOSS OF SIGHT.

Galileo's Labours at Arcetri.—Completion of the "Dialoghi delle Nuove Scienze."—Sends it to the Elzevirs at Leyden.—Method of taking Longitudes at Sea.—Declined by Spain and offered to Holland.—Discovery of the Libration and Titubation of the Moon.—Visit from Milton.—Becomes Blind.—Letter to Diodati.—On a hint from Castelli petitions for his Liberty.—The Inquisitor to visit him and report to Rome.—Permitted to live at Florence under Restrictions.—The States-General appoint a Delegate to see him on the Longitude Question.—The Inquisitor sends word of it to Rome.—Galileo not to receive a Heretic.—Presents from the States-General refused from fear of Rome.—Letter to Diodati.—Galileo supposed to be near his End.—Request that Castelli might come to him.—Permitted under Restrictions.—The new "Dialoghi" appear at Leyden, 1638.—They founded Mechanical Physics.—Attract much Notice.—Improvement of Health.—In 1639 goes to Arcetri again, probably not voluntarily.

Galileo was unceasingly active in his seclusion at Arcetri. In the year 1636 he completed his famous "Dialoghi delle Nuove Scienze."^[1] He also exerted himself, like a loving father who wishes to see his children provided for before he dies, about the preservation and republication of his works which were quite out of print. But all these efforts were frustrated by envy, ecclesiastical intolerance, and the unfavourable times. His cherished scheme of bringing out an edition of his collected works could neither be carried out by the French mathematician, Carcavy, who had warmly taken up the subject,^[2] nor by the Elzevirs through the mediation of Micanzio.^[3] He had also to give up his project of dedicating his "Dialoghi delle Nuove Scienze" to the German Emperor, Ferdinand II., and of publishing them at Vienna, as he learnt from his friend and former pupil there, Giovanni Pieroni, that his implacable foes, the Jesuits, were all-powerful; that Ferdinand himself was entirely under their influence; and moreover that his bitterest foe, Father Scheiner, was just then at Vienna.^[4] In the following year, however (1637), Pieroni succeeded by his prudent and untiring efforts, during the temporary absence of Scheiner, in obtaining a licence for Galileo's latest work,^[5] and afterwards one at Olmütz also; but meanwhile he had sent the MS. by Micanzio^[6] to be printed by the Elzevirs at Leyden, and, under the circumstances described by Pieroni, he did not prefer to bring out his book at a place where his bitterest enemies were in power.

He was at this time also deeply interested in a subject which originated as far back as 1610. It had occurred to him soon after the discovery of Jupiter's moons, by a series of observations of them, to make astronomical calculations and tables which would enable him to predict every year their configurations, their relative positions and occasional eclipses with the utmost precision; this would furnish the means of ascertaining the longitude of the point of observation at any hour of the night, which appeared to be of special importance to navigation. For hitherto the eclipses of the sun and moon had had to be employed for the purpose, which, however, on account of their rarity and the want of precise calculation, were neither entirely to be relied on nor sufficient. Galileo had offered his discovery,—the practical value of which he overrated,—in 1612, to the Spanish Government, and in 1616 tedious negotiations were carried on about it, which however led to no result, were then postponed till 1620, and in 1630 entirely given up.^[7] Now (August, 1636,) as he heard that the Dutch merchants had even offered a premium of thirty thousand scudi to any one who should invent a sure method of taking longitudes at sea, he ventured, without the knowledge of the Inquisition, to offer his invention to the Protestant States-General. Diodati at Paris was the mediator in these secret and ceremonious negotiations. On 11th November, Galileo's offer was entertained in the most flattering manner in the Assembly of the States-General, and a commission was appointed, consisting of the four savans, Realius, Hortensius, Blavius, and Golius, to examine into the subject and report upon it.^[8]

While Galileo was impatiently waiting for the decision that was never come to, he made his last great telescopic discovery, although suffering much in his eyes, that of the libration and titubation of the moon, about which he wrote his remarkable letter to Alfonso Antonini, bearing the signal date: "Delia mia carcere di Arcetri li 10 febbrajo 1637."^[9]

The complaint in Galileo's eyes grew rapidly worse. By the end of June the sight of the right eye was gone, and that of the other diminished with frightful rapidity from a constant discharge.^[10] But in spite of this heavy calamity, combined with his other sufferings, his interest in science did not diminish for a moment. Even at this sad time we find him carrying on a brisk correspondence with the learned men of Germany, Holland, France, and Italy, continuing his negotiations with the States-General with great zest,^[11] as well as occupying himself perpetually with astronomy and physics. He was indeed often obliged to employ the hand of another;^[12] but his mind worked on with undiminished vigour, even though he was no longer able to commit to paper himself the ideas that continually occupied him.

On 2nd September he received a visit from his sovereign, who came to console and encourage him in his pitiable situation.^[13] A few months later an unknown young man, of striking appearance from his handsome face and the unmistakable evidences which genius always exhibits, knocked at the door of the solitary villa at Arcetri: it was Milton, then twenty-nine years of age, who, travelling in Italy, sought out the old man of world-wide fame to testify his veneration.^[14]

In December of the same year Galileo became permanently quite blind, and informed Diodati of his calamity on 2nd January, 1638, in the following words:—

 

"In reply to your very acceptable letter of 20th November, I inform you, in reference to your inquiries about my health, that I am somewhat stronger than I have been of late, but alas! revered sir, Galileo, your devoted friend and servant, has been for a month totally and incurably blind; so that this heaven, this earth, this universe, which by my remarkable observations and clear demonstrations I have enlarged a hundred, nay, a thousand fold beyond the limits universally accepted by the learned men of all previous ages, are now shrivelled up for me into such narrow compass that it only extends to the space occupied by my person."^[15]

 

Up to the time when Galileo entirely lost his sight, absolutely nothing had been able to be done for his liberation at Rome. Even the faithful Castelli wrote on 12th September, to Galileo's son Vincenzo, that he had not been able to do anything whatever for his father; but he piously adds, "I do not fail every morning at holy mass to pray the Divine Majesty to comfort him, to help him, and to grant him His Divine grace."^[16] This precisely indicates the hopeless state of Galileo's affairs. Just then, during the first few days of December of the same year, darkness closed round him for ever; and not long afterwards, 12th December, Castelli suddenly wrote to him, that he had been given to understand that Galileo had not been forbidden in 1634 to send petitions direct to the Holy Office, but only through other persons.^[17] When the decided papal rescript of 23rd March, 1634,^[18] is compared with this curious interpretation of it, there can be no doubt that it was intended to enable the curia to take a more lenient view without direct collision with a former mandate. Galileo at once sent Castelli's letter to the Tuscan Court, with a request for instructions, as he did not wish to do anything without the concurrence of his sovereign.^[19] He was informed that he had better draw up a petition to the Holy Office, and get it handed in at Rome through Castelli.^[20] The latter had meanwhile informed himself under what formalities Galileo should make his request, and sent him on 19th January, 1638,^[21] a draught of the petition, with the remark that it must be sent, together with a medical certificate, direct to the assessor of the Congregation of the Holy Office; this Galileo immediately did. The petition was as follows:—

 

"Galileo Galilei, most humble servant of your most worthy Eminence, most respectfully showeth that whereas, by command of the Holy Congregation, he was imprisoned outside Florence four years ago, and after long and dangerous illness, as the enclosed medical certificate testifies, has entirely lost his eyesight, and therefore stands in urgent need of medical care: he appeals to the mercy of your most worthy Eminences, urgently intreating them in this most miserable condition and at his advanced age to grant him the blessing of his liberty."

 

The utmost caution was exercised at Rome before granting this petition. No confidence was placed in the medical certificate; but the Inquisitor-General of Florence, Father Fanano, was instructed to visit Galileo and to make an exact report of his health, and whether it was to be feared, if he lived at Florence, that he would promote the propagation of his errors.^[22] Fanano at once conscientiously executed his commission, and on 13th February, 1638, sent the following report to Cardinal Francesco Barberini:—

 

"In order the better to execute his Holiness's commission, I went myself, accompanied by a strange physician, an intimate friend of mine, to see Galileo, quite unexpectedly, at his villa at Arcetri, to find out the state he was in. My idea was not so much by this mode of proceeding to put myself in a position to report on the nature of his ailments, as to gain an insight into the studies and occupations he is carrying on, that I might be able to judge whether he was in a condition, if he returned to Florence, to propagate the condemned doctrine of the double motion of the earth by speeches at meetings. I found him deprived of his eyesight, entirely blind; he hopes for a cure, as the cataract only formed six months ago, but at his age of seventy the physician considers it incurable. He has besides a severe rupture, and suffers from continual weariness of life and sleeplessness, which as he asserts, and it is confirmed by the inmates of his house, does not permit him one hour's sound sleep in the twenty-four. He is besides so reduced that he looks more like a corpse than a living man. The villa is a long way from the city, and the access is inconvenient, so that Galileo can but seldom, and with much inconvenience and expense, have medical aid."^[23] His studies are interrupted by his blindness, though he is read to sometimes; intercourse with him is not much sought after, as in his poor state of health he can generally only complain of his sufferings and talk of his ailments to occasional visitors. I think, therefore, in consideration of this, if his Holiness, in his boundless mercy, should think him worthy, and would allow him to live in Florence, he would have no opportunity of holding meetings, and if he had, he is so prostrated that I think it would suffice, in order to make, quite sure, to keep him in check by an emphatic warning. This is what I have to report to your Eminence."^[24]

 

This report at last opened the eyes of Urban VIII. as to Galileo's real condition. The cry of distress from the blind old man, approaching dissolution, was too well justified to be wholly ignored, and a partial hearing was given to it at all events, at a sitting of the Congregation held on 25th February, under the presidency of the Pope.^[25] But a full release, in spite of the information that Galileo was more like a corpse than a living man, still appeared too dangerous to be ventured on. On 9th March Galileo received from the Inquisitor-General, Father Fanano, the following communication:—

 

"His Holiness is willing to allow you to remove from your villa to the house which you own in Florence, in order that you may be cured of your illness here. But on your arrival in the city you must immediately repair, or be taken, to the buildings of the Holy Office, that you may learn from me what I must do and prescribe for your advantage."^[26]

 

Galileo availed himself of the permission to return to his little house, Via della Costa, at Florence, on the very next day. Here the Inquisitor-General, as charged by the Holy Office, informed him, "for his advantage," of the order, not to go out in the city under pain of actual imprisonment for life and excommunication, and not to speak with any one whomsoever of the condemned opinion of the double motion of the earth.^[27] It was also enjoined upon him not to receive any suspicious visitors.

It is characteristic of the mode of proceeding of the Inquisition, that Fanano set Galileo's own son, who was nursing him with the tenderest affection, to watch over him. The Inquisitor enjoined upon Vincenzo to see that the above orders were strictly obeyed, and especially to take care that his father's visitors never stayed long. He remarks, in a report to Francesco Barberini of 10th March, that Vincenzo could be trusted, "for he is very much obliged for the favour granted to his father to be medically treated at Florence, and fears that the least offence might entail the loss of it; but it is very much to his own interest that his father should behave properly and keep up as long as possible, for with his death a thousand scudi will go, which the Grand Duke allows him annually." In the opinion of the worthy Father Fanano, then, the son must be anxious for his father's life for the sake of the thousand scudi! In the same letter the Inquisitor assured Barberini that he would himself keep a sharp look out that his Holiness's orders were strictly obeyed, which, as we shall soon see, he did not fail to do.

Galileo's confinement in Florence was so rigorous that at Easter a special permission from the Inquisition was required to allow him to go to the little Church of San Georgio, very near his house, to confess, to communicate, and to perform his Easter devotions,^[28] and even this permission only extended expressly to the Thursday, Good Friday, Saturday, and Easter Sunday.^[29] On the other hand, as appears from the dates of his letters,^[30] he was allowed, during June, July, and August, to go several times to and fro between his villa at Arcetri and Florence.

Galileo was now once more to discover how rigidly he was watched by the Inquisition. His negotiations with the States-General, in spite of the urgent intercession of such men as Diodati, Hortensius, Hugo Grotius, Realius, Constantine Huyghens (Secretary of the Prince of Orange, and father of the celebrated Christian Huyghens), and others, had not led to any result. His proposed method of taking longitudes at sea, well worked out as it was theoretically, presented many difficulties in practical application. His methods of precisely determining the smallest portions of time, and of overcoming the obstacles occasioned by the motion of the vessel, did not prove to be adequate.^[31] He had endeavoured, in a long letter to Realius of 6th June, 1637,^[32] to dismiss or refute all the objections that had been made; but this did not suffice, and although the States-General acknowledged his proposal in the main in the most handsome terms, even accepted it, and offered him a special distinction (of which presently), it appeared necessary to have some personal consultation on the subject with the inventor. For this purpose, Hortensius, who had also a great desire to make Galileo's acquaintance, was to go to Florence.^[33] The Inquisitor-General heard that a delegate was coming from Germany to confer with Galileo on the subject. He at once reported this on 26th June to Rome,^[34] whence he received instructions under date of 13th July from the Congregation of the Holy Office, that Galileo must not receive the delegate if he were of a heretical religion, or from a heretical country, and the Inquisitor will please communicate this to Galileo; on the other hand, there was nothing to prevent the interview if the person came from a Catholic country, and himself belonged to the Catholic religion; only, in accordance with the previous regulations, the doctrine of the double motion of the earth must not be spoken of.^[35]

A few days after the Inquisitor had delivered his instructions to Galileo, the German merchants of the name of Ebers residing in Florence, presented him in the name of the Dutch Government with a very flattering letter, and a heavy gold chain, as a recognition of his proposals and a pledge of the ultimate adjustment of the negotiations. The envoys of the States-General found Galileo very ill in bed, his blinded eyes continually running and very much inflamed. He felt the gold chain, which he could not see, and had the letter read to him. He then handed the chain back to the merchants, on the plea that he could not keep it now, as the negotiations had been interrupted by his illness and loss of sight, and he did not at all know whether he should ever be in a position to carry them through.^[36] The real motive, however, was nothing but fear of the Inquisition,^[37] and as the sequel showed, he was quite right. Fanano sent a report on 25th July of all these circumstances to Cardinal Barberini at Rome. It is so characteristic that we cannot refrain from giving it:—

"The person who was to come to see Galileo has neither appeared in Florence, nor is likely to appear, so far as I am informed; but I have not yet been able to learn whether in consequence of some hindrance on the journey or from some other cause. I know, however, that presents for Galileo and a letter to him have come to some merchants here. A highly estimable person, who is in my confidence, and has spoken with the person who has the presents and letter in charge, told me that both bear the seal of the Dutch Government; the presents are in a case, and may be gold or silver work. Galileo has steadily refused to accept either the letter or the presents, whether from fear of incurring some danger, on account of the warning I gave him on the first news of the expected arrival of an envoy, or whether because he really could not perfect his method of taking longitudes at sea, and is not in a state to do it; for he is now quite blind, and his head is more in the grave than fit for mathematical studies. Insurmountable difficulties had also occurred in the use of the instruments indicated by him. Besides, it is said here, that if he had fully brought his plan to perfection, his Highness (Ferdinand II. of Tuscany) would never have permitted it to pass into the hands of renegades, heretics, or enemies of the allies of his house. This is what I have to report to your Eminence."^[38]

The news that Galileo had not accepted the distinction offered him by the Dutch Government gave great satisfaction at Rome; and Urban VIII. even charged the Inquisitor at Florence, by a mandate of 5th August, to express to Galileo the gratification of the Holy Congregation at his conduct in this affair.^[39]

About this time he was sunk so low, physically as well as mentally, that he and every one thought his dissolution was at hand. In a letter to Diodati of 7th August, in which he told him of his interview with the German merchants at Florence, he expressed the fear that "if his sufferings increased as they had done during the last three or four days, he would not even be able to dictate letters."^[40] He added, perhaps in reference to the Inquisitor's intimation of 13th July: "It would be a fruitless undertaking if Signor Hortensius were to take the trouble to come and see me, for if he found me living (which I do not believe), I should be quite unable to give him the least satisfaction."

His profound vexation about the regulations imposed upon him in this matter by the Roman curia is very evident in a letter to Diodati of 14th August. He writes:—

"As ill luck would have it, the Holy Office came to know of the negotiations I was carrying on about the geographical longitude with the States-General, which may do me the greatest injury. I am extremely obliged to you for having induced Signor Hortensius to give up his intended journey, and thereby averted some calamity from me which would probably have been in store for me if he had come. It is indeed true that these negotiations ought not to do me any harm, for the just and obvious reasons that you mention, but rather to bring me fame and honour, if my circumstances were but like those of other men, that is, if I were not pursued by misfortune more than others. But having been often and often convinced by experience of the tricks fate plays me, I can but expect from its obstinate perfidy, that what would be an advantage to any one else will never bring anything but harm to me. But even in this bitter adversity I do not lose my peace of mind, for it would be but idle audacity to oppose inexorable destiny."^[41]

Galileo, who thought his hours were numbered, dictated his will on 21st August, in the presence of a notary and witnesses, and directed that he should be buried in the family vault of the Galilei in the Church of Santa Croce at Florence.^[42] On 8th September the Grand Duke paid the dying astronomer, as was supposed, a visit of two hours, and himself handed him his medicine.^[43]

It had been for a long time a cherished wish of Galileo's to have with him during the evening of his days his most devoted and favourite disciple, Father Castelli.^[44] But the professorship which he held at Rome made the attainment of this wish difficult. As it was now supposed that a speedy death would deprive the world of the great philosopher, the Grand Duke requested through Niccolini at Rome that Castelli might come to Florence, for a few months at least, that he might yet receive from the lips of his dying master many ideas of importance for science, which he might not perhaps confide to any but his trusted friend.^[45] After some difficulties were surmounted, he actually received the papal consent, but only on condition that a third person should always be present during the conversations with Galileo.^[46] Early in October Castelli arrived in Florence, where the Inquisitor-General, as charged by the Holy Office, gave him permission to visit Galileo, with the express prohibition, under pain of excommunication, to converse with him on the condemned doctrine of the earth's double motion.^[47] The permission, however, to visit Galileo seems to have been very limited, for Castelli repeatedly wrote to Cardinal Francesco Barberini, with the most urgent entreaties to obtain an extension of it for him from the Pope. Castelli protests in this letter that he would rather lose his life than converse with Galileo on subjects forbidden by the Church. He gives as a reason for the need of more frequent interviews that he had received from the Grand Duke the twofold charge to minister to Galileo in spiritual matters, and to inform himself fully about the tables and ephemerides of the Medicean stars, because the Prince Giovanni Carlo, Lord High Admiral, was to take this discovery to Spain.^[48] The cardinal replied that in consideration of these circumstances. Urban VIII. granted permission for more frequent visits to Galileo, under the known conditions;^[49] but the official permission, was not issued until about November.^[50] Nothing is known in history, however, of the Lord High Admiral's having ever taken Galileo's method of taking longitudes to the Peninsula.

During the same year (1638), the Elzevirs at Leyden issued Galileo's famous work: "Discourses on and Demonstrations of Two New Sciences appertaining to Mechanics and Motion."^[51] This work, known under the abridged title, "Dialoghi delle Nuove Scienze," was dedicated to the Count de Noailles, in grateful remembrance of the warm interest which he had always shown in the author.^[52] It is the most copious and best of all Galileo's writings, and he himself valued it more highly than any of the others.^[53] In it he created the new sciences of the doctrine of cohesion in stationary bodies, and their resistance when torn asunder; also that of phoronomics, and thereby opened up new paths in a field of science that had been lying fallow. He must, indeed, be regarded as the real founder of mechanical physics. It is not our province to enter farther into the contents of this work, or its importance for science. It has, however, some significance in our historical review of Galileo's relations with the curia, for it excited immense attention in all learned circles, and increasingly attracted the notice of the scientific world to the prisoner of the Inquisition. This was by no means agreeable to the Romanists, who would have been glad to see him sink into oblivion. Galileo now again received communications from all countries, some of them expressing the highest admiration of his new work, and others asking more information on many of the theories expounded. And we now behold the shattered old man of seventy-four, only partially recovered from his severe illness, carrying on an extensive correspondence full of the most abstruse problems in physics and mathematics.^[54]

In January, 1639, as his health had so far improved as to allow the hope to be indulged that he might be spared some time longer, he returned to his villa at Arcetri, not to leave it again alive. Was this move a voluntary one? We have no document which finally settles the question. But we hold ourselves justified in doubting it. Not only because it is difficult to reconcile a voluntary return to Arcetri with his previous efforts to obtain permission to reside in Florence, but there is a later letter from him bearing the expressive date: "From the Villa Arcetri, my perpetual prison and place of exile from the city."^[55] And when the wife of Buonamici, who was distinguished for her mental powers, gave him a pressing invitation to Prato, which is only four miles from Florence, he reminds her in his reply of 6th April, 1641, that "he was still a prisoner here for reasons which her husband was well aware of"; he then presses her to visit him at Arcetri, adding: "Do not make any excuses, nor fear that any unpleasantness may accrue to me from it, for I do not trouble myself much how this interview may be judged by certain persons, as I am accustomed to bearing many heavy burdens as if they were quite light."^[56] From such utterances it is clear that Galileo had little pleasure in residing at Arcetri, and that therefore his second banishment from Florence was not voluntary, but was the result of a papal order.^[57]

1. Comp. Galileo's letters to Micanzio at Venice of 21st and 28th June 1636. (Op. vii. pp. 63-66.)
2. Op. x. pp. 88, 89, 104, 105, 116-118, 191, 192; vii. pp. 132, 154, 155.
3. Op. x. pp. 157. 158, 165, 170, 171, 213; vii. 63, 64, 67, 68, 71, 138, 253.
4. Op. x. pp. 66-69, 108-111, 127-130.
5. Pieroni to Galileo, 9th July, 1637. (Op. x. pp. 222-226.)
6. Comp. Op. vii. pp. 138, 139, 152, 153; x. pp. 167 and 184.
7. Comp. Op. vi. pp. 238-276, 338-346.
8. Op. vii. pp. 73-93, and 136, 137.
9. Op. iii. pp. 176-183.
10. Comp. Galileo's letter to Diodati of 4th July, 1637. (Op. vii. p. 180.)
11. Comp. Op. vii. pp. 163-174, 190-204; x. pp. 215-218, 228-248; Suppl. pp. 282-284.
12. Op. vii. p. 193.
13. Op. x. pp. 231, 232.
14. . . . "Here I found and called upon the celebrated Galileo, now become old and a prisoner of the Inquisition," says Milton. Unfortunately we know nothing more of this interesting meeting. (Comp. Reumont, p. 405.)
15. Op. vii. p. 207. See on Galileo's total blindness, "Sull'epoca vera e la durata della cecità del Galileo," Nota del Angelo Secchi: (Estratta dal Giornale Arcadico, Tomo liv nuova serie); and "Sull' nella epoca della completa cecità del Galileo," Risposta di Paolo Volpicelli al chiaris e R. P. A. Secchi, Roma, 1868.
16. Op. x. p. 232.
17. Op. x. pp. 248, 249.
18. Comp. p. 275, note 1.
19. Galileo's letter to Guerrini, an official at the Tuscan Court, 19th December. (Op. vii. pp. 204, 205.)
20. Guerrini to Galileo, 20th December. (Op. x. pp. 249, 250.)
21. Op. x. pp. 254, 255.
22. Gherardi's Documents, Doc. xxiii.
23. This passage directly contradicts the remark on this subject in the report of Fra Clemente, the Inquisitor, of 1st April, 1634; his successor, Fra Fanano, seems to have been more favourable to Galileo.
24. Op. x. pp. 280, 281.
25. Gherardi's Documents, Doc. xxiv.
26. Op. x. p. 286.
27. Fanano's letter to Cardinal F. Barberini of 10th March, 1638. (Op. x. p. 287.)
28. Gherardi's Documents, Doc. xxv.
29. Letter of the Vicar of the Holy Office at Florence to Galileo, of 28th March, 1638. (Op. x. p. 292.)
30. Op. vii. pp. 211-216.
31. See letters from Hortensius and Realius to Galileo of 26th Jan. and 3rd Mar. 1637 (Op. vii. pp. 95-99, 100-102); letter from Const. Huyghens to Diodati, 13th April, 1637 (Op. vii. pp. 111-113).
32. Op. vii. pp. 163-174.
33. Op. vii. pp. 181-189.
34. Vat. MS. fol. 554 ro.
35. Vat. MS. fol. 555 vo.; and Gherardi's Documents, Doc. xxvi.
36. On all this see Galileo's letter to Diodati of 7th Aug., 1638. (Op. vii pp. 214-216.)
37. Comp. Nelli, vol. ii. pp. 678, 679, and Venturi, vol ii. p. 285.
38. Vat. MS. fol. 553 ro.; and Op. x. 304, 305, where it is dated 23rd nstead of 25th July.
39. Vat. MS. fol. 556 vo.; and Gherardi's Documents, Doc. xxvii.
40. Op. vii. p. 215.
41. Op. vii. pp. 216-218.
42. Op. xv. p. 401; Nelli, vol. ii. p. 838.
43. Op. xv. (Viviani), p. 371.
44. Comp. Castelli's letters to Galileo of 29th May and 30 July, 1638. (Op. x. pp. 300, 310-313.)
45. Cioli's despatch to Niccolini of 9th Sept., 1638. (Op. x. pp. 313, 314.)
46. Niccolini's despatches to Cioli of 15th and 25th Sept. (Wolynski, "La Diplomazia Toscana," etc., pp. 68, 69.)
47. Fanano's letter to Card. Barberini of 4th Oct. (Op. x. p. 314.)
48. See Castelli's letters to Card. F. Barberini of 2nd, 9th, and 16th Oct., in Pieralisi, pp. 291-296; and another of 23rd Oct., 1638, on an unnumbered page between fols. 552 and 553 of the Vat. MS. p. 175.
49. See Card. Barberini's letters to Castelli of 16th and 30th Oct. (Pieralisi, pp. 294, 295, and 298.)
50. Vat. MS. fol. 557 vo.
51. "Discorsi e Dimostrazione Matematiche intorno a due Scienze attenenti alla Meccanica e ai Movimenti Locali. Con una Appendice del Centro di gravita di alcuni Solidi."
52. See Galileo's letter to the Count de Noailles of 6th March, 1638, and his answer of 20th July. (Op. vii. pp. 209-211, and x. pp. 308-310.)
53. Comp. Op. vii. pp. 44, 46, 57, 70.
54. Op. vii. pp. 218-226; x. pp. 316, 317, 320, 321.
55. "Dalla Villa Arcètri, mio continuato carcere ed esilio dalla città." (Letter from Galileo to Cassiano dal Pozzo in Rome, of 20th Jan., 1641, Op. vii. p. 351.)
56. Op. vii. pp. 364, 365.
57. Pieralisi thinks ("Urbano VIII. and Galileo Galilei," p. 264) that it was left to Galileo's option during the last few years to reside either at Arcetri or Florence, and that his preference for his villa led him to choose the former; a statement for which Pieralisi has no proof to offer, and which is strongly opposed to what we have mentioned above.