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was likened to the movement of fish in the water ; but he explained that flight was due to the elasticity of the air on being compressed in alternating falls.1
We shall consider briefly, under three sub-headings, some of his discoveries in Light, Heat, and Sound.
(a) Light: He invented the camera-obscura. Here are his words : 'If you place yourself in a hermetically sealed room facing a landscape, a building, or any other object, and cut a small circular hole in the shutter, an image of the object outside will be thrown on the opposite wall reversed.' Cardan, fifty years later, discovered that a lens placed in the opening will increase the size and sharpen the definition of the image.
As would naturally be expected from the famous painter, he writes with great acumen about colors. Amongst other things he treats of the effect of the juxtaposition of colors, e.g., that red gains in intensity when placed beside green. In this he anticipated Chevreul, who gets credit for it. Also he anticipated him in noting the effect of color on the complexion : ‘ Black clothes make the complexion look whiter than it is, white clothes make it look darker, yellow clothes heighten people's color, and red makes them seem pale.'
(6) Heat : He discovered that fire needs oxygen, and laid down the useful principle in regard to dangerous gases, 'No animal can live where a flame cannot live.' He knew of the effect of the concave mirror, and of rays of heat reflected from a glass ball filled with cold water. Above all, he knew of the force of steam, and in view of the following it is not unreasonable to suppose that, had he concentrated on the subject, Watt might never have been heard of, at least in connexion with the steam-engine. He constructed a copper cannon with two chambers at the back, in the lower one was placed lighted charcoal, and in the upper one, water; by turning a screw he made the water fall on the charcoal, whereupon the generated steam 'drove a ball weighing one talent (about 60 lbs.) over a distance of six stadia (six furlongs) with great fuss and fury.' Surely from this to working a piston was not a long distance. In the
1 See Duhem : Cath. Encyc., under 'Physics.' 2 De subtilitate rerum, 1550.
3 It is said Aristotle noticed that if a square hole were cut in a window shutter, the beam of light from the sun described a circle on the wall ; but he did not push the investigation further.
museum of Valenciennes is a drawing by him of a spit which was turned by steam or rarified air.
(c) Sound: He noticed that 'a blow struck on one bell produces a sympathetic effect on another bell; that when the string of a lute is struck it corresponds with and conveys a movement to a similar string of the same tone on another lute, as one may convince oneself by placing a straw on the string similar to the one struck' (his own words). 'Who would believe,' says Govi, 'that these notes and observations anticipated those of Galileo, Mersenne, and others, which, however, they did by more than a century?'ı
It would be too much to claim that he had a presentiment of the telephone, yet the following statement of his is of interest : ‘If you bring your ship to and put one end of a tube in the water and the other end to your ear, you will hear ships which are quite a long way off ; and if you do the same thing on land, you will hear what is going on far away from where you are.
Aeronaut: In a lecture recently delivered in Paris on the history of the aeroplane, Leonardo's name held a prominent place, and rightly so, as his manuscripts and many drawings prove. He contrived wings, flying cars, and winged chairs, and made therefor a close observation of the flight of birds, as his sketches show. He also invented the screw by which aeroplanes are at present driven, and invented it chiefly for that purpose. Likewise the screw by which ships are propelled is his. A drawing of it, with the vertical axis around which it worked, can be seen in the Institut de France. But more important than any o those mechanical devices is the fact that he was the first to propound, and strenuously adhere to, the idea of a heavier than air machine as the one that would succeed. The idea lay in abeyance until it was taken up by Graham Bell, inventor of the telephone (I am here speaking from personal knowledge, as I heard the latter refer to the matter at a lecture in New York). The Wright Brothers had confidence in Bell's theory and reduced it to practice; the rest is recent and current history. So here it is in a nutshell : Da Vinci ; Graham Bell; the Wright Brothers.
1 As quoted by Müntz: Leonardo da Vinci, vol. ii. p. 79.
4 Son of Melville Bell, the elocutionist, and kinsman of David Bell, author of Bell's Speaker.
He also invented the parachute. The following words of his leave no doubt on the point : ‘If a man has a pavilion (a tent) of starched linen, of which each face measures twelve cubits square, he may throw himself from any height whatever without fear of danger.
Of an Archimedean turn of mind, his inventions can be numbered by the score. For instance : a dynamo-meter for testing machines and the strength of animals; a saw, still in use in the quarries of Carrara; a rope-making, and wire-drawing, machine; several machines for the people of Milan for cutting and polishing rock-crystal and marble; a machine for mincing meat for sausages ; machines for laminating iron, for making screws, cylinders, files, and saws; a gold-beater's hammer; a machine for digging ditches, and one driven by wind for tilling soil; paddle-wheels for boats, and lamps with double currents of air. He played with marvellous adaptability with beams, cranes, supports, escapements, and, above all
, with levers, pulleys and cog-wheels. I saw an extraordinary combination of these latter in McGill University, Montreal, and was not surprised when I was told that the inventor was Leonardo. In his writings there are fragments by the hundred, enough to constitute a treatise on physics.
In addition, he spent much time in providing surprises of a quaint kind. When Louis XII entered Milan, Leonardo constructed a mechanical lion which walked across the room, opened its mouth, and dropped a bouquet of fleursde-lis at his feet. He once deceived some naturalists by pretending that he had discovered a hit ierto unknown lizard. This was one he painted in fantastic fashion, attached a pair of horns and a beard, also a pair of wings, obtained by flaying another lizard, into which he poured some drops of quicksilver so that they partook of its movement. These and such like were but fads, for the purpose of mental relaxation. But it was no mere mental relaxation, nor shallow curiosity, that led him to spend whole days amongst his strange collection of bats, lizards, reptiles, wasps, and nearly all kinds of insects, studying, dissecting, and even painting them. On the contrary--and here is the unifying principle running through his work-he wanted to pluck from nature the heart of her mystery, by knowing her in all her varieties and moods, and then mirroring her in art. But she proved too much for him, and seemed to mock his ambition, as his Mona Lisa ironically smiles at
the baffled gaze of all who strive to know the secret of her expression-a secret known only to the artist himself who felt the lure and the mystery of nature, and gave them pictorial expression in this his most personal and characteristic canvas. But enough-and if this latter appears to be a deviation from Leonardo the scientist, it is because every appreciation, as needle to the pole, will finally swing round to Leonardo the artist.
A word in conclusion as to the personality of the man. In appearance, as his portrait proves, he was remarkably handsome ; of such great strength that, it is said, he could bend a horse-shoe as if it were made of lead ; full of wit and humour, when he chose to let his thought-troubled brow relax; he was popular amongst his fellow-artists, and the idol of the tatterdemalions of Florence and Milan; in disposition, so amiable and gentle that his nearest approach to a harsh reply was his retort to the brusque and domineering Michael Angelo-who, as Raphael said, used to walk the street like an executioner--that he was famous before he was born ; of sympathy, so wide and tender that he used not only help fellow-beings in distress, but loved bird and beast, and many a story is told how, with his spare cash, -never indeed too flush-he used buy caged birds in the market-places of both cities for the sheer pleasure of setting them free. But for all that he was sad, not alone with the sadness that so often comes to those who live from a great depth of being, but sad--and his portrait in premature old-age proves it-because he felt the shadows closing round, while his manuscripts—those sibyline leaves of science-remained unedited, and his life-work not half done; ay, and sad too for a still more personal reason, because the taint of illegitimacy in birth ever struck, like cold upon a nerve, on his sensitive soul.
This is an imperfect sketch-a mere barrow of tumbled facts—but even so, it may give some idea of this marvellous man. Greater geniuses, no doubt, there have been, men of a more Aristotelian or Newtonian grasp of mind; but if the wide page of history holds the name of a more versatile genius than Leonardo da Vinci, the writer of this article has to confess his ignorance, in that he has yet to learn whose is that name.
P. A. BEECHER.
OUR ATTITUDE TOWARDS NATIONAL PROHIBITION AND LOCAL OPTION, CONSIDERED AS IRISH POLICIES
By REV. D. DINNEEN, D.D.
I-PROHIBITION PROHIBITION, in its restricted sense, is a legal enactment which puts a ban on intoxicating drinks used for beverage purposes. If the enactment area is local, you have Local Prohibition ; if the enactment is for a whole country, it is called National Prohibition.
National Prohibition may forbid merely the sale of intoxicants for beverage purposes; or it may forbid the manufacture for export as well as the sale; or it may forbid the importation of intoxicants also. The history of the Prohibition movement in the United States has fairly conclusively shown, as we might have expected, that Prohibition does not prohibit, that it is practically a failure, except it prohibits, not only the manufacture and sale of intoxicants, but also their importation.
Prohibition bans alcoholic liquors, but only for use as beverages; alcohol for medicinal, industrial or sacramental purposes does not come within its scope. But it is necessary here to emphasize a rather important point of Catholic principle. The State has the power, if it so wills, and if circumstances call for its exercise, to forbid the use of alcohol, for industrial, and even for medicinal, purposes. But it has no right under any circumstances whatsoever to forbid the use of alcohol for sacramental purposes. Were it to do so it would be acting absolutely ultra vires ; it would be usurping a jurisdiction to which it can never rightly lay claim, and would be bringing itself into collision with an authority which, in its own domain, must ever
Paper read at Catholic Total Abstinence Federation Congress, September,