At Bordeaux in Gascony the sea rises about 40 braccia before its ebb, and the river there is filled with salt water for more than a hundred and fifty miles; and the vessels which are repaired there rest high and dry on a high hill above the sea at low tide. [Footnote 2: This is obviously an exaggeration founded on inaccurate information. Half of 150 miles would be nearer the mark.]

1072.

The Rhone issues from the lake of Geneva and flows first to the West and then to the South, with a course of 400 miles and pours its waters into the Mediterranean.

1073.

c d is the garden at Blois; a b is the conduit of Blois, made in France by Fra Giocondo, b c is what is wanting in the height of that conduit, c d is the height of the garden at Blois, e f is the siphon of the conduit, b c, e f, f g is where the siphon discharges into the river. [Footnote: The tenor of this note (see lines 2 and 3) seems to me to indicate that this pa.s.sage was not written in France, but was written from oral information. We have no evidence as to when this note may have been written beyond the circ.u.mstance that Fra Giocondo the Veronese Architect left France not before the year 1505. The greater part of the magnificent Chateau of Blois has now disappeared. Whether this note was made for a special purpose is uncertain. The original form and extent of the Chateau is shown in Androvet, Les plus excellents Bastiments de France, Paris MDCVII, and it may be observed that there is in the middle of the garden a Pavilion somewhat similar to that shown on Pl. Lx.x.xVIII No. 7.

See S. DE LA SAUSSAYE, Histoire du Chateau de Blois 4eme edition Blois et Paris p. 175: En mariant sa fille ainee a Francois, comte d'Angouleme, Louis XII lui avait const.i.tue en dot les comtes de Blois, d'Asti, de Coucy, de Montfort, d'Etampes et de Vertus. Une ordonnance de Francois I. lui laissa en 1516 _l'administration du comte de Blois.

Le roi fit commencer, dans la meme annee, les travaux de celle belle partie du chateau, connue sous le nom d'aile de Francois I, et dont nous avons donne la description au commencement de ce livre. Nous trouvons en effet, dans les archives du Baron de Foursanvault, une piece qui en fixe parfaitement la date. On y lit: "Je, Baymon Philippeaux, commis par le Roy a tenir le compte et fair le payement des bastiments, ediffices et reparacions que le dit seigneur fait faire en son chastu de Blois, confesse avoir eu et receu ... la somme de trois mille livres tournois ... le cinquieme jour de juillet, l'an mil cinq cent et seize._ P. 24: _Les jardins avaient ete decores avec beaucoup de luxe par les differents possesseurs du chateau. Il ne reste de tous les batiments qu'ils y eleverent que ceux des officiers charges de l'ad_ministration et de la culture des jardins, et un pavilion carre en pierre et en brique flanque de terra.s.ses a chacun de ses angles. Quoique defigure par des mesures elevees sur les terra.s.ses, cet edifice est tris-digne d'interet par l'originalite du plan, la decoration architecturale et le souvenir d'Anne de Bretagne qui le fit construire._ Felibien describes the garden as follows: _Le jardin haut etait fort bien dresse par grands compartimens de toutes sortes de figures, avec des allees de meuriers blancs et des palissades de coudriers. Deux grands berceaux de charpenterie separoient toute la longueur et la largeur du jardin, et dans les quatres angles des allees, ou ces berceaux se croissent, il y auoit 4 cabinets, de mesme charpenterie ... Il y a pas longtemps qu'il y auoit dans ce mesme jardin, a l'endroit ou se croissent les allees du milieu, un edifice de figure octogone, de plus de 7 thoises de diametre et de plus de neuf thoises de haut; avec 4 enfoncements en forme de niches dans les 4 angles des allies. Ce bastiment.... esloit de charpente mais d'un extraordinairement bien travaille. On y voyait particulierement la cordiliere qui regnati tout autour en forme de cordon. Car la Reyne affectait de la mettre nonseulement a ses armes et a ses chiffres mais de la faire representer en divers manieres dans tous les ouvrages qu'on lui faisait pour elle ... le bastiment estati couvert en forme de dome qui dans son milieu avait encore un plus pet.i.t dome, ou lanterne vitree au-dessus de laquelle estait une figure doree representant Saint Michel. Les deux domes estoient proprement couvert d'ardoise et de plomb dore par dehors; par dedans ils esloient lambrissez d'une menuiserie tres delicate. Au milieu de ce Salon il y avait un grand ba.s.sin octogone de marbre blanc, dont toutes les faces estoient enrichies de differentes sculptures, avec les armes et les chiffres du Roy Louis XII et de la Reine Anne, Dans ce ba.s.sin il y en avait un autre pose sur un piedestal lequel auoit sept piedz de diametre. Il estait de figure ronde a G.o.drons, avec des masques et d'autres ornements tres scauamment taillez. Du milieu de ce deuxiesme ba.s.sin s'y levoit un autre pet.i.t piedestal qui portait un troisiesme ba.s.sin de trois pieds de diametre, aussy parfaitement bien taille; c'estoit de ce dernier ba.s.sin que jallissoit l'eau qui se rependoit en suitte dans les deux autres ba.s.sins. Les beaux ouvrages faits d'un marbre esgalement blanc et poli, furent brisez par la pesanteur de tout l'edifice, que les injures de l'air renverserent de fond en comble.]

1074.

The river Loire at Amboise.

The river is higher within the bank b d than outside that bank.

The island where there is a part of Amboise.

This is the river that pa.s.ses through Amboise; it pa.s.ses at a b c d, and when it has pa.s.sed the bridge it turns back, against the original current, by the channel d e, b f in contact with the bank which lies between the two contrary currents of the said river, a b, c d, and d e, b f. It then turns down again by the channel f l, g h, n m, and reunites with the river from which it was at first separated, which pa.s.ses by k n, which makes k m, r t. But when the river is very full it flows all in one channel pa.s.sing over the bank b d. [Footnote: See Pl. CXV. Lines 1-7 are above, lines 8-10 in the middle of the large island and the word Isola is written above d in the smaller island; a is written on the margin on the bank of the river above 1. I; in the reproduction it is not visible. As may be seen from the last sentence, the observation was made after long study of the river's course, when Leonardo had resided for some time at, or near, Amboise.]

1075.

The water may be dammed up above the level of Romorantin to such a height, that in its fall it may be used for numerous mills.

1075.

The river at Villefranche may be conducted to Romorantin which may be done by the inhabitants; and the timber of which their houses are built may be carried in boats to Romorantin [Footnote: Compare No. 744.]. The river may be dammed up at such a height that the waters may be brought back to Romorantin with a convenient fall.

1076.

As to whether it is better that the water should all be raised in a single turn or in two?

The answer is that in one single turn the wheel could not support all the water that it can raise in two turns, because at the half turn of the wheel it would be raising 100 pounds and no more; and if it had to raise the whole, 200 pounds in one turn, it could not raise them unless the wheel were of double the diameter and if the diameter were doubled, the time of its revolution would be doubled; therefore it is better and a greater advantage in expense to make such a wheel of half the size (?) the land which it would water and would render the country fertile to supply food to the inhabitants, and would make navigable ca.n.a.ls for mercantile purposes.

The way in which the river in its flow should scour its own channel.

By the ninth of the third; the more rapid it is, the more it wears away its channel; and, by the converse proposition, the slower the water the more it deposits that which renders it turbid.

And let the sluice be movable like the one I arranged in Friuli [Footnote 19: This pa.s.sage reveals to us the fact that Leonardo had visited the country of Friuli and that he had stayed there for some time. Nothing whatever was known of this previously.], where when one sluice was opened the water which pa.s.sed through it dug out the bottom. Therefore when the rivers are flooded, the sluices of the mills ought to be opened in order that the whole course of the river may pa.s.s through falls to each mill; there should be many in order to give a greater impetus, and so all the river will be scoured. And below the site of each of the two mills there may be one of the said sluice falls; one of them may be placed below each mill.

1078.

A trabocco is four braccia, and one mile is three thousand of the said braccia. Each braccio is divided into 12 inches; and the water in the ca.n.a.ls has a fall in every hundred trabocchi of two of these inches; therefore 14 inches of fall are necessary in two thousand eight hundred braccia of flow in these ca.n.a.ls; it follows that 15 inches of fall give the required momentum to the currents of the waters in the said ca.n.a.ls, that is one braccio and a half in the mile. And from this it may be concluded that the water taken from the river of Ville-franche and lent to the river of Romorantin will..... Where one river by reason of its low level cannot flow into the other, it will be necessary to dam it up, so that it may acquire a fall into the other, which was previously the higher.

The eve of Saint Antony I returned from Romorantin to Amboise, and the King went away two days before from Romorantin.

>From Romorantin as far as the bridge at Saudre it is called the Saudre, and from that bridge as far as Tours it is called the Cher.

I would test the level of that channel which is to lead from the Loire to Romorantin, with a channel one braccio wide and one braccio deep.

[Footnote: Lines 6-18 are partly reproduced in the facsimile on p. 254, and the whole of lines 19-25.

The following names are written along the rivers on the larger sketch, era f (the Loire) scier f (the Cher) three times. Pote Sodro (bridge of the Soudre). Villa francha (Villefranche) banco (sandbank) Sodro (Soudre). The circle below shows the position of Romorantin. The words 'orologio del sole' written below do not belong to the map of the rivers. The following names are written by the side of the smaller sketch-map:-tors (Tours), Abosa (Amboise) bres-for Bles (Blois) mo rica (Montrichard). Lione (Lyons). This map was also published in the 'Saggio' (Milano, 1872) Pl. XXII, and the editors remark: Forse la linia retta che va da Amboise a Romorantin segna l'andamento proposto d'un Ca.n.a.le, che poi rembra prolungarsi in giu fin dove sta scritto Lione.

M. Ravaisson has enlarged on this idea in the Gazette des Beaux Arts (1881 p. 530): Les traces de Leonard permettent d'entrevoir que le ca.n.a.l commencant soit aupres de Tours, soit aupres de Blois et pa.s.sant par Romorantin, avec port d'embarquement a Villefranche, devait, au dela de Bourges, traverser l'Allier au-dessous des affluents de la Dore et de la Sioule, aller par Moulins jusqu' a Digoin; enfin, sur l'autre rive de la Loire, depa.s.ser les monts du Charolais et rejoindre la Saone aupres de Macon. It seems to me rash, however, to found so elaborate an hypothesis on these sketches of rivers. The slight stroke going to Lione is perhaps only an indication of the direction.-With regard to the Loire compare also No. 988. l. 38.]

1079.

THE ROAD TO ORLEANS

At 1/4 from the South to the South East. At 1/3 from the South to the South East. At 1/4 from the South to the South East. At 1/5 from the South to the South East. Between the South West and South, to the East bearing to the South; from the South towards the East 1/8; thence to the West, between the South and South West; at the South.

[Footnote: The meaning is obscure; a more important pa.s.sage referring to France is to be found under No. 744]

On the Germans (1080. 1081).

1080.

The way in which the Germans closing up together cross and interweave their broad leather shields against the enemy, stooping down and putting one of the ends on the ground while they hold the rest in their hand. [Footnote: Above the text is a sketch of a few lines crossing each other and the words de ponderibus. The meaning of the pa.s.sage is obscure.]

1081.

The Germans are wont to annoy a garrison with the smoke of feathers, sulphur and realgar, and they make this smoke last 7 or 8 hours. Likewise the husks of wheat make a great and lasting smoke; and also dry dung; but this must be mixed with olive husks, that is olives pressed for oil and from which the oil has been extracted. [Footnote: There is with this pa.s.sage a sketch of a round tower shrouded in smoke.]

The Danube.

1082.

That the valleys were formerly in great part covered by lakes the soil of which always forms the banks of rivers,-and by seas, which afterwards, by the persistent wearing of the rivers, cut through the mountains and the wandering courses of the rivers carried away the other plains enclosed by the mountains; and the cutting away of the mountains is evident from the strata in the rocks, which correspond in their sections as made by the courses of the rivers [Footnote 4: Emus, the Balkan; Dardania, now Servia.], The Haemus mountains which go along Thrace and Dardania and join the Sardonius mountains which, going on to the westward change their name from Sardus to Rebi, as they come near Dalmatia; then turning to the West cross Illyria, now called Sclavonia, changing the name of Rebi to Alba.n.u.s, and going on still to the West, they change to Mount Ocra in the North; and to the South above Istria they are named Caruancas; and to the West above Italy they join the Adula, where the Danube rises [8], which stretches to the East and has a course of 1500 miles; its shortest line is about l000 miles, and the same or about the same is that branch of the Adula mountains changed as to their name, as before mentioned. To the North are the Carpathians, closing in the breadth of the valley of the Danube, which, as I have said extends eastward, a length of about 1000 miles, and is sometimes 200 and in some places 300 miles wide; and in the midst flows the Danube, the princ.i.p.al river of Europe as to size. The said Danube runs through the middle of Austria and Albania and northwards through Bavaria, Poland, Hungary, Wallachia and Bosnia and then the Danube or Donau flows into the Black Sea, which formerly extended almost to Austria and occupied the plains through which the Danube now courses; and the evidence of this is in the oysters and c.o.c.kle sh.e.l.ls and scollops and bones of great fishes which are still to be found in many places on the sides of those mountains; and this sea was formed by the filling up of the spurs of the Adula mountains which then extended to the East joining the spurs of the Taurus which extend to the West. And near Bithynia the waters of this Black Sea poured into the Propontis [Marmora] falling into the Aegean Sea, that is the Mediterranean, where, after a long course, the spurs of the Adula mountains became separated from those of the Taurus. The Black Sea sank lower and laid bare the valley of the Danube with the above named countries, and the whole of Asia Minor beyond the Taurus range to the North, and the plains from mount Caucasus to the Black Sea to the West, and the plains of the Don this side-that is to say, at the foot of the Ural mountains. And thus the Black Sea must have sunk about 1000 braccia to uncover such vast plains.

[Footnote 8: Danubio, in the original Reno; evidently a mistake as we may infer from come dissi l. 10 &c.]

III.

THE COUNTRIES OF THE WESTERN END OF THE MEDITERRANEAN.

The straits of Gibraltar (1083-1085).

1083.

WHY THE SEA MAKES A STRONGER CURRENT IN THE STRAITS OF SPAIN THAN ELSEWHERE.

A river of equal depth runs with greater speed in a narrow s.p.a.ce than in a wide one, in proportion to the difference between the wider and the narrower one.

This proposition is clearly proved by reason confirmed by experiment. Supposing that through a channel one mile wide there flows one mile in length of water; where the river is five miles wide each of the 5 square miles will require 1/5 of itself to be equal to the square mile of water required in the sea, and where the river is 3 miles wide each of these square miles will require the third of its volume to make up the amount of the square mile of the narrow part; as is demonstrated in f g h at the mile marked n.