Dante wrote his first sonnet on the 15th of June, 1282; in the spring of 1300 he wrote the Vita Nuova; on the 3rd of April he began his great poem.[196] Darwin had the earliest ideas of his great work first in March, then in June.[197] Petrarch conceived the Africa in March, 1338. Michelangelo’s great cartoon, the work which so competent a judge as Cellini considered his most wonderful masterpiece, was imagined and executed between April and July, 1506. Manzoni wrote his 5 Maggio in summer. Milton’s great poem was conceived in the spring. Galileo discovered Saturn’s ring in April, 1611. Balzac wrote La Cousine Bette in August and September, Père Goriot in September, La Recherche de l’Absolu in June to September. Sterne began Tristram Shandy in January, the first of his sermons in April, the famous one on errors of conscience in May.[198] Giordano Bruno composed his Candelajo in July; and in his witty dedication he attributed it to the heat of the dog-days. Voltaire wrote Tancred in August. Byron wrote the fourth canto of Childe Harold in September, his Prophecy of Dante in June, his Prisoner of Chillon during the summer in Switzerland. Giusti wrote of Gingillino and Pero: “Here are the only leaves that April has drawn out of my head after fourteen months of idleness.” Schiller, it appears from his letters to Goethe, conceived Don Carlos and Wallenstein in the autumn, as well as Fiesco and Wilhelm Tell; Wallensteins Lager and Letters on Æsthetics in September; Kabale und Liebe in winter; the Magician, the Glove, the Ring of Polycrates, the Cranes of Ibycus, and Nadowessir’s Song in June; the Jungfrau von Orleans in July. Goethe wrote Werther in autumn; Mignon and other lyric poems in May; Cellini, Alexis, Euphrosyne, Metamorphosis of Plants, and Parnass in June and July; the Xenien, Hermann und Dorothea, Westöstlichen Divan, and Natürliche Tochter in winter. In the first days of March, 1788, which, he wrote, were worth more to him than a whole month, he dictated, besides other poems, the beginning of Faust.[199] Salorno’s hymn to Liberty was written in May. Rossini composed the Semiramide almost entirely in February, and in November the last part of the Stabat Mater.[200] Mozart composed the Mitridate in October; Beethoven his ninth symphony in February.[201] Donizetti composed Lucia di Lammermoor, perhaps entirely, in September; in any case, the famous Tu che a Dio spiegasti l’ale belongs to that date; the Figlia del Reggimento was also composed in autumn; Linda de Chamounix in spring; Rita in summer; Don Pasquale and the Miserere in winter.[202] Wagner composed Der Fliegende Holländer in the spring of 1841. Canova modelled his first work, Orpheus and Eurydice, in October.[203] Michelangelo conceived his Pietà between September and October, 1498,[204] the design of the Libreria in December, the model in wood of the tomb of Pope Julius in August.[205] Leonardo da Vinci conceived the equestrian statue of the Sforza and began his book Della luce e delle Ombre in April; for we find in his autograph manuscript these words: “On April the 23rd, 1492, I commenced this book and recommenced the horse.” On the 2nd of July, 1491, he designed the pavilion of the Duchess’s Bath; on the 3rd of March, 1509, St. Christopher’s Canal.[206] The first idea of the discovery of America came to Columbus between May and June, in 1474, in the form of a search for the western passage to India.[207] Galileo discovered the sun’s spots contemporaneously with, or before, Scheiner in April, 1611;[208] in December, 1610, and even in September (since he speaks of his observation having been made three months previously), he discovered the analogy between the phases of Venus and those of the moon; in May, 1609, he invented the telescope;[209] in July, 1610, he discovered two stars, afterwards found to be the most luminous points of Saturn’s ring, a discovery which, according to his custom, he expressed in verse:—
“Altissimum planetam tergeminum observavi.”
In January he found Jupiter’s satellites; in November, 1602, the isochronism of the oscillations of the pendulum.[210]
Kepler discovered the law which bears his name in May, 1618; the discovery of Zucchi regarding Jupiter took place in May; that of Tycho Brahe in November. Fabricius discovered the first changing star in August, 1546. Cassini discovered the spots which indicate the rotation of Venus in October and April (1666-67), and in October, December, and March (1671, 1672, 1684) four satellites of Saturn. Herschel discovered two in March, 1789. In June, 1631, Hevelius conceived the first ideas of selenography.[211] A satellite of Saturn was discovered by Huygens on the 25th of March, 1665; another by Dawes and Bond on the night of the 19th of September, 1848. Two satellites of Uranus were discovered by Herschel in 1787; one of them, considered as doubtful by Herschel, was again discovered by Struve and Lassel in October, 1847; the last, Ariel, was discovered by Lassel on the 14th of September, 1847; on the 8th of July in the same year he had also seen Neptune’s satellite for the first time.[212] Uranus was discovered by Herschel in March, 1781. The same astronomer observed the moon’s volcanoes in April. Bradley discovered in September (1728) the aberration of light, Enke’s and Vico’s fine observations on Saturn took place in March and April (1735-38). Of the comets discovered by Gambart, three were in July, two in March and in May, one in January, April, June, August, October, December.[213] The last three comets discovered in 1877 were perceived in October, February, and September; in August Hall observed the satellites of Mars. Schiaparelli’s discovery on falling stars dates from August, 1866.
We read in Malpighi’s journal that in July he made his great discoveries in the suprarenal glands. It is curious to observe how some one month predominates in certain years: for example, January in 1788 and 1790, and June in 1771, during which he made thirteen discoveries.[214]
The first idea of the barometer came to Torricelli in May, 1645, as may be seen by his letters to Ricci; in March, 1644, he had made the discovery, of great moment at that time, of the best way of making glasses for spectacles. The first experiments of Pascal on the equilibrium of fluids were made in September, 1645.[215] In March, 1752, Franklin began his experiments with lightning conductors, and concluded them in September.
Goethe declared that it was in May that his original ideas on the theory of colours arose, and in June that he made his fine observations on the metamorphoses of plants.[216] Hamilton discovered the calculus of Quaternions on the 16th of October, 1843.
Volta invented the electric pile in the beginning of winter, 1799-1800. In the spring of 1775 he invented the electrophore. In the first days of November, 1784, he discovered the production of hydrogen in organic fermentations. His invention of the eudiometer took place in the spring, about May. In April of the same year (1777) Volta wrote to Barletta the famous letter in which he divined the electric telegraph. In the spring of 1788 he constructed his great conductor.
Luigi Brugnatelli found out galvanoplasty in November, 1806, as is shown by a letter which the advocate Zanino Volta found in the correspondence of his grandfather. Nicholson discovered the oxydation of metals by means of the Voltaic pile, in the summer of 1800.
From the examination of Galvani’s manuscripts it appears that his studies on intestinal gases began in December, 1713. His first studies on the action of atmospheric electricity on the nerves of cold-blooded animals were undertaken, as he himself writes, “at the 20th hour of the 26th of April, 1776.” In September, 1786, he began his experiments on the contractions of frogs, whence the origin of galvanism. In November, 1780, he stated his experiments on the contractions of frogs by artificial electricity.[217]