Pམཔ| posite? (I am assuming, for argument sake, that the photog true rendering of any optical image, which, in strictness, Suppose a succession of many different pictures are to b each for the same brief period, and if a single other picture fifty times in succession, or for fifty times as long, would the generic image be fifty times as large as that of any of t if not, what would its share be? The reply is, that both in the photographic composite an cesses of numerical statistics, its effect would be exactly fi great, but in mental imagery this would certainly not be th therein lies a fertile source of error in our general impressi made some experiments on the subject, which are not as ye advanced to be worth recording, but I may say that at p nothing in the results incompatible with the very reasonal tion that the relation between the varying periods of expos strength of the corresponding mental impression follows Weber. This law is founded in the fact that the more highl are stimulated, the more is their discriminative power blu a double number of candles does not double the apparent i it only increases it by a certain amount, which is alway whether the light of a single candle be added to that of an candle, or the light of a 1,000 candles be added to that of a candles. The law is true of all the senses. The difference of by dropping one shilling or two shillings on a table, is not tinguished by the ear, neither is that of discharging one o guns from the turret of the same ironclad ship, as was sh dence concerning the recent frightful accident on board the er.' That is to say, the same increment of noise may be p the fall of a shilling on a table, in the one case, as by a 38 the other. Let me take the present opportunity of saying that of Weber's law is that a true composite never appears true, a what our uncorrected senses teach us to expect. If we mix grey with a very light grey, we might on first thoughts their mixture would appear to be a medium grey, but Web us that the eye judges differently, and we find, in trying ment, that the mixture is brighter than we had expected. 3 3 Weber's law may be well illustrated by placing in a row, say, five quite black, each the size of half a sheet of note-paper. Then taking of white note-paper, tear it in half and lay one-half on card 5 so as to co Tear the remaining half exactly across its middle, and lay one-half L M 2-3 we could learn by much practice to correct the judgment of our senses, but it is only in rare and special cases that we have the necessary practice. I have often noticed my own ludicrous failures in estimating the relative depths of two parts of the same pool by the relative obscurity of the bottom. Maps of ocean depths are never made on what may be called natural scales, but always on symbolic ones, in which consecutive increases of tint, as judged by the eye, correspond to successive increases of depth. According to Weber's law (which I content myself here with expressing in its original and approximative form) if it requires a tenfold period of exposure to make a doubly deep impression on the mind, it would require a hundredfold period to make a trebly deep one, a thousandfold period to make it quadruply deep, and so The one series follows an arithmetical, the other a geometrical on. progression. Whatever the true law may be that connects the strength of the impression with the time that the object is before our eyes, or with the frequency with which it is seen, its form is certainly not very dissimilar to that of the law of Weber. Otherwise it would not accord with the fact that sights on which we have not lingered, often leave abiding impressions, while the pictures that hang on our walls, before our eyes, every day of our life are not always remembered with vivid distinctness. The effect of the law, whatever its precise form may be, is to prevent generic images from having the same definition and simplicity as the corresponding photographs. The most extreme elements will always leave their traces very visibly because the medium elements are not present in sufficient number to overpower them. These images cannot be otherwise than blurred and surrounded by monstrous and faint imagery. The attention is unable to deal with such pictures, because when it is engaged on one part of them the remainder slips out of memory. All parts of an image must be congruous and well defined before the attention can sweep so swiftly over the entire field of view as practically to bring it all at once into sight. If an image is incongruous and vague, the mind follows the course already described when the illustration was used of a clergyman in a pulpit. The conclusions to be drawn from what I have said are that composite portraits are perfectly trustworthy when made by optical means and with proper precautions, and that photographic composites are as correct representations of these as photographs ever are of the pictures again tear the remainder in half and lay one-half on card 3. Proceed similarly up to card 1; the fragment that remains is not wanted. Cut these papers into shreds (excepting No. 5, which can be left as it is), and distribute the shreds as evenly as possible over their respective cards. Then 1 will have one portion of white, 2 will have two portions, 3 will have four portions, 4 will have eight, and 5, which is wholly covered with white, will have sixteen. The effect of the scattered white on the cards is to produce various greys which the eye will judge to be separated by equal intervals of tint. Card 4, which contains eight portions, has the medium amount of white (eight and a half is the precise medium), but the eye reckons differently; it places the medium tint at card 3, which contains only four portions of white. from which they are taken. Composite portraits are therefore to be considered as pictorial statistics. Also it is conceivable that general mental images should sometimes closely resemble these portraits except in one important respect; namely, that the effect produced by the huge bulk of ordinary facts is never in proportion to their numbers. Consequently we find that undue consideration is inevitably given in generic images to all exceptional cases. When the exceptions in excess are balanced by those in deficiency, the value of the average will not be affected, and there is always a tendency towards that result. The fault that remains wholly uncorrected is that the great prevalence of mediocre instances is overlooked, and the number and importance of the deviations are largely over-estimated. The tendency of the mind of the child and of the savage, and in all branches of knowledge in their pre-scientific stage, is necessarily towards the marvellous and the miraculous. The generic images that might arise in a mind superhumanly logical and active would be subject to no other error than this, but in the human mind it is not so. Some of the images in every presumed generic group are sure to be aliens to the genus and to have become associated to the rest by superficial and fallacious resemblances, such as common minds are especially attentive to. Again, the number of pictures that are blended together is sure to fall far short of the whole store that would be available if the memory were immeasurably stronger than it is, and more ready in its action. Knowing also, as I do, from considerable experience of composites, what monstrous and abortive productions may result from ill-sorted combinations of portraits, and how much care in selection and nicety of adjustment is required to produce the truest possible generic image, I cease to wonder at the numerous shortcomings in our generalisations and at their absurd and frequent fallacies. The human mind is a most imperfect apparatus for the elaboration of true general ideas. Compared with the mind of brutes, its powers are marvellous; but for all that they fall vastly short of perfection. The criterion of a perfect mind would be the power of always creating vivid images of a truly generic kind, deduced from the whole range of its past experiences. General impressions are the faint traces left by generic images, and have all their defects, as well as others due to their own want of definition. They are never to be trusted. Unfortunately, when general impressions are of long standing they become fixed rules of life, and assume a prescriptive right not to be questioned. Consequently those who are not accustomed to original inquiry entertain a hatred and horror of statistics. They cannot endure the notion of submitting their sacred general impressions to cold-blooded verification. But it is the triumph of scientific men to rise superior to such superstitions, to devise tests by which the value of beliefs may be ascertained, and to feel sufficiently masters of themselves to discard contemptuously whatever may be found untrue. FRANCIS GALTON, in Nineteenth Century. HIDDEN TREASURES: TORLONIA MUSEUM. Whoever has read Winckleman's Letters will remember the enthusiasm he showed when he wrote of Cardinal Albani and of the Villa Albani, with its then remarkable collection of ancient sculpture. "This cardinal," says the celebrated German archeologist, "is the greatest antiquary living. He brings to light of day that which was buried in darkness, and he pays with the generosity of a king. What a man he is! He is over seventy-three, but he has the head of a man of sixty, and builds as if he were sure of living a quarter of a century longer.' Change the name of Cardinal Albani to Prince Torlonia and these encomiums are as perfect in application, except that the prince of our day has done much more than the prelate of Winckleman's time. He has drained an immense lake-that of Fucino-a labour which the emperors of ancient Rome, with all their unlimited means, were not able to accomplish,-and thereby restored acres of land to the cultivator. As for galleries of art, the cardinal's collection at the Albani Villa was much inferior to those of Prince Torlonia's. Setting aside other works of art which the Prince has in various palaces, the Roman Lungara sculpture-gallery alone rivals in rarity and value most of the famous collections of other cities, without excluding the museums of Rome. In the Lungara-Roman Trastevere nearly opposite the beautiful Farnesina, and beside the Corsini Palace, is a little street called Via delle Scuderie-street of the stables-so named from the stables that were used in former days by the Corsini. In the seventeenth century, when Queen Christina of Sweden held literary court in the Corsini Palace, she also stabled her horses and housed her splendid coaches in those ample scuderie. In these ci-devant stables, Prince Torlonia has established a provisional gallery for a matchless collection of sculpture. This museum is not open to the public. Indeed it is a difficult matter to obtain permission to see it. Probably not a dozen persons outside the Prince's art-council have had the good fortune to visit this fine collection which is so jealously shut out from the world. A little garden surrounds the building. Last spring I used to find the walk leading from the entrance gate to the first gallery white with orange-blossoms; they lay as thick as December snows; the path was shaded by the branches of orange-trees, and bordered by great bushes full of superb roses. I have sat alone on a June afternoon in the "Prometheus" "Venus" cabinet, or in front of the beautiful seated "Livia,” "Lapped in pleasant visions." or The soft air came stealing in through the thin walls of cloth, heavily *Winckleman's Lettres fam. Amsterdam, 1871. laden with the sweetest of all odours mingled together-rose and orange. The supremest silence reigned. Then I understood why the Prince keeps these galleries jealously shut out from the world he knows so well. He wishes to possess, for a short while at least, a refined luxury that passeth the possession of kingdoms; to enjoy there a solitude of "high thoughts" outvaluing many lifetimes of vulgar reputation. In this Lungara Torlonia Museum is a great treasure of erudition as well as art, which has been collected with tranquil silence, critical care, and patient study, during the course of at least thirty years. Year after year the Prince has summoned about him remarkable men, among whom Baron Visconti, nephew of the great Ennio Quirino Visconti, whose memory is closely associated with the fine sculpture-galleries of Rome and Paris, has been the most intimate confidant of his projects, acquisitions, and decisions. Each new statue, bust, or bas-relief, has been examined with the most scrupulous and critical eyes; also compared with ancient medals and coins, and passages from ancient and modern writers. Of these important meetings careful journals of proceedings have been constantly made; thus a valuable æsthetical and artistic unpublished literature has collected about those Lungara halls. When a statue was found in fragments, it was carefully put together. An accomplished sculptor, an expert in his art, Professor Guaccarini has devoted his entire professional life to the work of the Museum, aided by the counsels of the Prince and his learned assistants. One of the most remarkable groups of the collection,-Hercules and Telephus,—when found at Porto, was in almost unrecognisable little fragments. Baron Visconti, who was present at the excavation, and who knew the history of that superb suburb of Ostia, recognised the bits as belonging to a valuable work of art. Others thought not; but the workmen were obliged by an imperious command of the Baron to gather the small pieces carefully together, and put them in a large basket which the persistent archeologist took away with him in his own carriage. Two weeks after, these fragments were sufficiently united to prove the truth of Visconti's assertion; his well-practised artistic eyes were not likely to be at fault. Through Baron Visconti's patience and Guaccarini's skill the group was afterwards restored to its present complete state, and offers to us a specimen of antique art most curious in form and development, and which in justice ought to be known to the future visitors to the Museum as the Ercole Visconti. Prince Torlonia has gone on from year to year with steady persistence, spending freely, and maturing this one fine idea,-the creating of a unique gallery of sculpture in the form of a private museum. He has found in this pleasant labour a relaxation from his severer occupations,―a noble pastime. In his gallery is a Minerva more perfect in some respects than the Minervas of the Vatican and Capitoline; a Venus that some say is surpassed only by that of Milo-other connoisseurs even go so far as to assert that the celebrated Milo statue may be regarded as inferior to the Torlonia Venus; an Apollo that is a gem, |