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of publishing such of their works as lonna, Lucas Valerio, Guiducci, Welser, should be thought worthy of appearing Giovanni Fabro, Terrentio, Virginio Cewith the common sanction. Such libe- sarini, Ciampoli

, Molitor, Cardinal Barral offers were not likely to meet with berino, (nephew of Pope Urban VIII.) an unfavourable reception: they were Stelliola, Salviati, &c. thankfully accepted by many well quali- The principal monument still remainfied to carry his design into execution, ing of the zeal and industry to which and Cesi was soon enabled formally to Cesi incited his academicians is the open his academy, the distinctive title Phytobasanos, a compendium of the of which he borrowed from the Lynx, natural history of Mexico, which must with reference to the piercing sight be considered a surprising performance which that animal has been supposed to for the times in which it appeared. It possess. This quality seemed to him an was written by a Spaniard named Herappropriate emblem of those which he' nandez; and Řeccho, who often has the desired to find in his academicians, for credit of the whole work, made great adthe purpose of investigating the secrets ditions to it. During fifty years the maof nature; and although, at the present nuscript had been neglected, when Cesi day, the name may appear to border on discovered it, and employed Terrentio, the grotesque, it was conceived in the Fabro, and Colonna, allLynceans, to spirit of the age, and the fantastic names publish it enriched with their notes and of the numberless societies which were emendations. Cesi himself published rapidly formed in various parts of Italy several treatises,two of which are extant; far exceed whatever degree of quaint- his Tabulæ Phytosophicæ, and a Disserness may be thought to belong to the tation on Bees entitled Apiarium, the Lyncean name. The Inflamed — the only known copy of which last is in the Transformed — the Uneasy the Hu- library of the Vatican. His great work, morists—the Fantastic—the Intricate Theatrum Nature, was never printed; the Indolent-the Senseless--the Un- a circumstance which tends to shew that deceived the Valiant -- the Ætherial he did not assemble the society round Societies are selected from a vast num- him for the purpose of ministering to his ber of similar institutions, the names of own vanity, but postponed the publicawhich, now almost their sole remains, tion of his own productions to the laare collected by the industry of Morhof Hours of his coadjutors. This, and many and Tiraboschi*. The Humorists are other valuable works belonging to the named by Morhof as the only Italian academy existed in manuscript till lately philosophical society anterior to the in the Albani Library at Rome. Cesi Lynceans; their founder was Paolo collected, not a large, but an useful liMancino, and the distinctive symbol brary for the use of the academy, (which which they adopted was rain dropping was afterwards augmented on the prefrom a cloud, with the motto Redit ag- mature death of Cesarini by the donamine dulci ;—their title is derived from tion of his books); he filled a botanical the same metaphor. The object of their garden with the rarer specimens of union appears to have been similar to plants, and arranged a museum of natuthat of the Lynceans, but they at no ral curiosities; his palace at Rome was time attained to the celebrity to which constantly open to the academicians; his Cesi's society rose from the moment of purse and his influence were employed its incorporation. Cesi took the presi- with equal liberality in their service. dency for his life; and the celebrated Cesi's death, in 1632, put a sudden Baptista Porta was appointed vice pre- stop to the prosperity of the society, a sident at Naples. Stelluti acted as the consequence which may be attributed legal representative of the society, with to the munificence with which he had the title of procuratore. Of the other from the first sustained it: no one two original members Anastasio de Filiis could be found to fill his place in the was dead, and although Hecke returned princely manner to which the academito Italy in 1614, and rejoined the Aca- cians were accustomed, and the society, demy, yet he was soon afterwards struck after lingering some years under the nooff the list in consequence of his lapsing minal patronage of Urban VIII., grainto insanity. Among the academicians dually decayed, till, by the death of its we find the names of Galileo, Fabio Co- principal members, and dispersion of the whose sketch of the academy was with the laws and history of their fellowalmost the only one till the appearance ship; and I hope the like in due time of Odescalchi's history, made an attempt from our Royal Society; that so such as to revive it in the succeeding century, envie their fame and felicity, and such but without any permanent effect. A as suspect their ability and candor, may society under the same name has been be silenced and disappointed in their deformed since 1784, and is still flourish- tractions and expectations." ing in Rome. Before leaving the subject it may be mentioned, that one of the earliest notices that Bacon's works were

• Polyhistor Literarius, &-.--Storia della Letterat. rest, it became entirely extinct*. Bianchi, Ital. The still existing society of Chaff, more generally known by its Italian title, Della Crusca, belongs to the same period.

* F. Colonna Phytabasanus Jano Planco Auctore. Florent, 1744.

CHAPTER X. known in Italy is to be found in a letter Spots on the Sun-Essay on Floating to Cesi, dated 1625; in which Pozzo, Bodies--Scheiner— Change in Sawho had gone to Paris with Cardinal turn. Barberino, mentions having seen them there with great admiration, and sug- GALILEO did not indulge the curiosity gests that Bacon would be a fit person of his Roman friends by exhibiting only to be proposed as a member of their the wonders already mentioned, which society. After Galileo's death, three of now began to lose the gloss of novelty, his principal followers, Viviani, Torri- but disclosed a new discovery, which apcelli, and Aggiunti formed the plan of es- peared still more extraordinary, and, to tablishing a similar philosophical society, the opposite faction, more hateful than and though Aggiunti and Torricelli died anything of which he had yet spoken. before the scheme could be realized, This was the discovery, which he first Viviani pressed it forward, and, under made in the month of March, 1611, of the auspices of Ferdinand II., formed a dark spots on the body of the sun. A society, whịch, in 1657, merged in the curious fact, and one which well serves to famous Academia del Cimento, or Ex- illustrate Galileo's superiority in seeing perimental Academy. This latter held things simply as they are, is, that these its occasional meetings at the palace of spots had been observed and recorded Ferdinand's brother, Leopold de Medici: centuries before he existed, but, for want it was composed chiefly, if not entirely, of careful observation, their true nature of Galileo's pupils and friends. During had been constantly misapprehended. the few years that this society lasted, one One of the most celebrated occasions of the principal objects of which was was in the year 807 of our era, in which declared to be the repetition and deve- a dark spot is mentioned as visible on lopement of Galileo's experiments, it the face of the sun during seven or eight kept up a correspondence with the prin- days. It was then supposed to be Mercipal philosophers in every part of Eu- cury". Kepler, whose astronomical rope, but when Leopold was, in 1666, knowledge would not suffer him to overcreated a cardinal, it appears to have look that it was impossible that Mercury been dissolved, scarcely ten years after could remain so long in conjunction with its institutiont. This digression may be the sun, preferred to solve the difficulty excused in favour of so interesting an by supposing that, in Aimoin's original establishment as the Academia Lincea, account, the expression was not octo which preceded by half a century the dies (eight days), but octoties--a barbaformation of the Royal Society of Lon- rous word, which he supposed to have don, and Académie Françoise of Paris. been written for octies (eight times); and

These latter two are mentioned toge that the other accounts in which the ther, probably for the first time, by Sa- number of days mentioned is different) lusbury. The passage is curious in an his- copying loosely from the first, had both torical point of view, and worth extract- mistaken the word, and misquoted the ing:-"In imitation of these societies, time which they thought they found menParis and London have erected theirs of ioned there. It is impossible to look Les Beaux Esprits, and of the Virtuosi : on this explanation as satisfactory, but the one by the countenance of the most Kepler, who at that time did not dream eminent Cardinal Richelieu, the other by of spots on the sun, was perfectly conthe royal encouragement of his sacred tented with it. In 1609, he himself obMajesty that now is. The Beaux Esprits served upon the sun a black spot, which have published sundry volumes of their he in like manner mistook for Mercury, moral and physiological conferences, and unluckily the day, being cloudy, did

• Nelli Saggio di Storia Literaria Fiorentina, * Salusbury's Math. Coll. vol. ii. London, 1664. Lucca, 1759.

Aimoini Hist. Francorum. Parisiis. 1567.

not allow him to contemplate it suffici- him." To this he afterwards subjoined, ently long to discover his error, which that, by continued observation, he had the slowness of its apparent motion would satisfied himself that these solar spots soon have pointed out.* He hastened to were in actual contact with the surface publish his supposed observation, but no of the sun, where they are continually sooner was Galileo's discovery of the solar appearing and disappearing; that their spots announced, than he, with that figures were very irregular, some being candour which as much as his flighty very dark, and others not so black; that disposition certainly characterized him one would often divide into three or four, at all times, retracted his former opinion, and, at other times, two, three, or more and owned his belief that he had been would unite into one ; besides which, mistaken. In fact it is known from the that they had all a common and regular more accurate theory which we now pos- motion, with which they revolved round sess of Mercury's motions, that it did not with the sun, which turned upon its axis pass over the sun's face at the time when in about the time of a lunar month. Kepler thought he perceived it there. Having by these prefatory observa

Galileo's observations were in their tions assuaged the public thirst for asconsequences to him particularly unfor- tronomical novelties, he ventures to intunate, as in the course of the contro troduce the principal subject of the treaversy in which they engaged him, he first tise above mentioned. The question of became personally embroiled with the floating bridges had been discussed at powerful party, whose prevailing influ- one of the scientific parties, assembled ence was one of the chief causes of his at the house of Galileo's friend Salviati, subsequent misfortunes. Before we enter and the general opinion of the comupon that discussion, it will be proper to pany appearing to be that the floating mention another famous treatise which or sinking of a body depended princiGalileo produced soon after his return pally upon its shape, Galileo undertook from Rome to Florence, in 1612. This to convince them of their error. If he is, his Discourse on Floating Bodies, had not preferred more direct arguments, which restored Archimedes' theory of he might merely have told them that in hydrostatics, and has, of course, met with this instance they were opposed to their the opposition which few of Galileo's favourite Aristotle, whose words are very works failed to encounter. In the com- unequivocal on the point in dispute. mencement, he thought it necessary to “Form is not the cause why a body apologize for writing on a subject so dif- moves downwards rather than upwards, ferent from that which chiefly occupied but it does affect the swiftness with the public attention, and declared that he which it moves ;"* which is exactly the had been too closely occupied in calcu- distinction which those who called themlating the periods of the revolutions of selves Aristotelians were unable to perJupiter's satellites to permit him to pub- ceive, and to which the opinions of Arislish anything earlier. These periods he totle himself were not always true. Gahad succeeded in determining during the lileo states the discussion to have immepreceding year, whilst at Rome, and he diately arisen from the assertion of some now announced them to complete their one in the company, that condensation is circuits, the first in about 1 day, 18, the effect of cold, and ice was mentioned hours; the second in 3 days, 13 hours, as an instance. On this, Galileo observed, 20 minutes; the third in 7 days, 4 hours; that ice is rather water rarefied than conand the outermost in 16 days, 18 hours. densed, the proof of which is, that ice All these numbers he gave merely as always floats upon water. It was reapproximately true, and promised to con- plied, that the reason of this phenomenon tinue his observations, for the purpose of was, not the superior lightness of the correcting the results. He then adds an ice, but its incapacity, owing to its flat announcement of his recent discovery of shape, to penetrate and overcome the the solar spots," which, as they change resistance of the water. Galileo denied their situation, offer a strong argument, this, and asserted that ice of any shape either that the sun revolves on itself, or would float upon water, and that, if a that, perhaps, other stars, like Venus and Mercury, revolve about it, invisible at all

+ For a discussion of this singular phenomenon, other times, on account of the small dis- sce 'Treatise on Heat, p. 12 ; and it is worth while to tance to which they are removed from remark in passing, what an admirable instance it

affords of Galileo's instantaneous abandonment of a

theory so soon as it became inconsistent with ex* Mercurius in sole visus. 1609.

periment.

* De Calo. lib. 4.

flat piece of ice were forcibly taken to The marrow of the dispute is included the bottom, it would of itself rise again in Galileo's assertion, that “The diversity to the surface. Upon this assertion it of figure given to any solid cannot be in appears that the conversation became so any way the cause of its absolutely sinkclamorous, that Galileo thought it perti- ing or floating ; so that if a solid, when nent to commence his Essay with the formed for example into a spherical following observation on the advantage figure, sinks or floats in the water, the of delivering scientific opinions in writ- same body will sink or float in the same ing, “ because in conversational argu- water, when put into any other form. ments, either one or other party, or per. The breadth of the figure may indeed haps both, are apt to get overwarm, and retard its velocity, as well of ascent as to speak overloud, and either do not descent, and more and more according suffer each other to be heard, or else, as the said figure is reduced to a greater transported with the obstinacy of not breadth and thinness; but that it may yielding, wander far away from the ori- be reduced to such a form as absolutely ginal proposition, and confound both to put an end to its motion in the same themselves and their auditors with the fluid, I hold to be impossible. In this novelty and variety of their assertions.” I have met with great contradictors After this gentle rebuke he proceeds with who, producing some experiments, and his argument, in which he takes occa- in particular a thin board of ebony, sion to state the famous hydrostatical and a ball of the same wood, and shewparadox, of which the earliest notice is ing that the ball in water sinks to the to be found in Stevin's works, a contem- bottom*, and that the board if put lightly porary Flemish engineer, and refers it to on the surface floats, have held and cona principle on which we shall enlarge in firmed themselves in their opinion with another chapter. He then explains the the authority of Aristotle, that the cause true theory of buoyancy, and refutes the of that rest is the breadth of the figure, false reasoning on which the contrary unable by its small weight to pierce and opinions were founded, with a variety of penetrate the resistance of the water's experiments.

thickness, which is readily overcome by The whole value and interest of expe- the other spherical figure."-For the purrimental processes generally depends on pose of these experiments, Galileo rea variety of minute circumstances, the commends a substance such as wax, detail of which would be particularly which may be easily moulded into any unsuited to a sketch like the present shape, and with which, by the addition one. For those who are desirous of be- of a few filings of lead, a substance may coming more familiar with Galileo's be readily made of any required specific mode of conducting an argument, it is gravity. He then declares that if a ball fortunate that such a series of experi- of wax of the size of an orange, or bigger, ments exists as that contained in this be made in this manner heavy enough essay; experiments which, from their to sink to the bottom, but so lightly that simplicity, admit of being for the most if we take from it only one grain of lead part concisely enumerated, and at the it returns to the top; and if the same same time possess so much intrinsic wax be afterwards moulded into a broad beauty and characteristic power of forc- and thin cake, or into any other figure, ing conviction. They also present an ad- regular or irregular, the addition of the mirable specimen of the talent for which same grain of lead will always make it Galileo was so deservedly famous, of in- sink, and it will again rise when we reventing ingenious arguments in favour move the lead from it.—“But methinks of his adversaries' absurd opinions before I hear some of the adversaries raise a he condescended to crush them, shew- doubt upon my produced experiment: ing that nothing but his love of truth and, first, they offer to my consideration stood in the way of his being a more that the figure, as a figure simply, and subtle sophist than any amongst them. disjunct from the matter, works no effect, In addition to these reasons for giving but requires to be conjoined with the these experiments somewhat in detail, matter; and, moreover, not with every is the fact that all explanation of one of matter, but with those only wherewith the principal phenomena to which they it may be able to execute the desired allude is omitted in many more modern operation. Just as we see by experience treatises on Hydrostatics; and in some it is referred precisely to the false doc

Ebony is one of the few woods heavier than trines here confuted.

See Treatise on Hydrostatics.

water.

that an acute and sharp angle is more hand, to the resistance of the matter to apt to cut than an obtuse; yet always be penetrated. And, since I have chosen provided that both one and the other are a matter which does penetrate the resistjoined with a matter fit to cut, as for in- ance of the water, and in all figures destance, steel. Therefore a knife with a scends to the bottom, my antagonists fine and sharp edge cuts bread or wood can charge me with no defect; nor (to with much ease, which it will not do if revert to their illustration) have I atthe edge be blunt and thick; but if, in- tempted to test the efficacy of acuteness stead of steel, any one will take wax and by cutting with matters unable to cut. mould it into a knife, undoubtedly he will I subjoin withal, that all caution, disnever learn the effects of sharp and tinction, and election of matter would blunt edges, because neither of them be superfluous and unnecessary, if the will cut; the wax being unable, by reason body to be cut should not at all resist of its flexibility, to overcome the hard- the cutting: if the knife were to be used ness of the wood and bread. And there- in cutting a mist, or smoke, one of paper fore, applying the like discourse to our would serve the purpose as well as one of argument, they say that the difference of Damascus steel; and I assert that this is figure will shew different effects with the case with water, and that there is not regard to floating and sinking, but not any solid of such lightness or of such a conjoined with any kind of matter, but figure, that being put on the water it only with those matters which by their will not divide and penetrate its thickweight are able to overcome the visco- ness; and if you will examine more sity of the water (like the ebony which carefully your thin boards of wood, you they have selected); and he that will will see that they have part of their select cork or other light wood to form thickness under water; and, moreover, solids of different figures, would in vain you will see that the shavings of ebony, seek to find out what operation figure stone, or metal, when they float, have has in sinking or floating, because all not only thus broken the continuity of would swim, and that not through any the water, but are with all their thickproperty of this or that figure, but ness under the surface of it; and that through the debility of the matter." more and more, according as the float

When I begin to examine one by one ing substance is heavier, so that a thin all the particulars here produced, I allow floating plate of lead will be lower than not only that figures, simply as such, do the surface of the surrounding water by not operate in natural things, but also that at least twelve times the thickness of the they are never separated from the corpo- plate, and gold will dive below the level real substance, nor have I ever alleged of the water almost twenty times the them to be stript of sensible matter : thickness of the plate, as I shall shew and also I freely admit, that in our en- presently." deavours to examine the diversity of In order to illustrate more clearly accidents which depend upon the variety the non-resistance of water to peneof figures, it is necessary to apply them tration, Galileo then directs a cone to matters which obstruct not the various to be made of wood or wax, and asoperations of those various figures. I serts that when it floats, either with its admit and grant that I should do very ill base or point in the water, the solid if I were to try the influence of a sharp content of the part immersed will be the edge with a knife of wax, applying it to same, although the point is, by its shape, cut an oak, because no sharpness in wax better adapted to overcome the resistis able to cut that very hard wood. But ance of the water to division, if that yet, such an experiment of this knife were the cause of the buoyancy. Or the would not be beside the purpose to cut experiment may be varied by tempering curded milk, or other very yielding mat- the wax with filings of lead, till it sinks ter; nay, in such matters, the wax is in the water, when it will be found that more convenient than steel for finding in any figure the same cork must be the difference depending on the acute- added to it to raise it to the surface.ness of the angles, because milk is cut “ This silences not my antagonists; but indifferently with a razor, or a blunt they say that all the discourse hitherto knife. We must therefore have regard made by me imports little to them, and not only to the hardness, solidity, or that it serves their turn, that they have weight of the bodies which, under dif- demonstrated in one instance, and in such ferent figures, are to divide some mat- manner and figure as pleases them best, ters asunder; but also, on the other namely, in a board and a ball of ebony,

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