Bridge-and to students having no access to a laboratory little satisfaction will be given when told: "The details of the construction and practical use of the different forms of Wheatstone's Bridge used in the measurement of resistance are best learnt in the laboratory, and for this reason we shall not give any further description of the arrangement.” In many instances the student is driven through a mass of theory before he has a fair idea of the general phenomena; thus in the introductory chapter on "Current Electricity," after a six-line description of a simple cell and current, over two pages are occupied in proving that the effects produced could be explained by the dissociation and procession of the hydrogen and oxygen atoms. The work is generally remarkably free from errors and misprints, but one occurs in the explanation just mentioned. The attraction of zinc for oxygen is said to be much greater than that of the copper, while later the zinc is also considered "to repel hydrogen less." Here, and in many other instances, the words to be emphasised are printed in italics. Another mistake will be found on pp. 168 and 169, where in comparing, by the method of oscillations, the field due to a magnet with that I+H_n12 of the earth, the author starts with the equation I na instead of I+H2, and reasoning correctly from this H n" false hypothesis, he deduces false results, while the answer to Ex. 8 on this part of the subject appears incorrect. Fig. 13, p. 201, in illustration of Oerstedt's experiment, is not correctly drawn. The arrangement of "calculations" and examples at the end of each chapter must prove extremely useful to students possessing beforehand an elementary knowledge of the general phenomena, and to such, rather than to the very beginner, the book may be commended. H. S. J. Manners and Monuments of Prehistoric Peoples. By the Marquis de Nadaillac. Translated by Nancy Bell (N. D'Anvers). (New York and London: G. P. Putnam's Sons, 1892.) A BOOK summing up in a popular style all that is now known with regard to prehistoric man would probably be welcomed by a tolerably large class of readers. The present work does not quite supply the kind of summary that is wanted. The author does not distinguish with sufficient clearness between the various periods with which he deals; he indulges too freely in talk of a vaguely moralising tendency; and some of his statements do not accord with the conclusions of the best authorities. Speaking of the Round Towers of Ireland, for instance, he says, "According to the point of view of different archæologists, they have been called temples of the sun, hermitages, phallic monuments, or signal towers." The reader is thus left to suppose that the question is still open, whereas all competent students of the subject accept the theory of the late Mr. Petrie, a theory which the Marquis de Nadaillac does not even mention. However, the author has presented a large number of interesting facts in the course of his exposition, and there are occasional passages in which he brings out very well the attractive elements of some of the more fascinating departments of archæology. LETTERS TO THE EDITOR. [The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he undertake to return, or to correspond with the writers of, rejected manuscripts intended for this or any other part of NATURE. No notice is taken of anonymous communications.] Two Statements. IN a letter addressed to the Daily Chronicle, dated January 25, 1893, Prof. Karl Pearson makes two statements respecting my opinions and grounds of action: 2 "As in society at large, so in academic matters, his mɔdə insuring progress is unlimited individual competition," and again : "he is an individualist in all matters." Seeing that in an essay "On Administrative Nihilism," p lished twenty-two years ago; and in another on "Govertre Anarchy or Regimentation," published in 1890, I have done best to combat the doctrine Prof. Pearson attributes to me, I be glad to know what justification he has to offer for so grar: misrepresentation. The purpose of it is obvious. T. H. HUXLEY Hodeslea, Eastbourne, January 29. A Meteor. THE following is taken from the Pretoria Weekly Pre January 7: "A few evenings ago a meteor of unusual se brilliancy was observed at Bloemfontein shooting right an the eastern sky. It looked like a rocket of a greenish coand burst in a shower of sparks in the south-east. The tacle was much admired by those who were fortunate enough witness it." This meteor, as seen in South Africa, appears to have b many points in common with a similar one seen in E about the same time, and reported by several observers in daily Press. W. L. DISTAN Purley, Surrey, January 31. "Hare-lip" in Earthworms. ATTENTION has recently been drawn by Prof. An Gossip, 1892) to some abnormal conditions of life an (American Naturalist, September, 1892) and myself terrestrial annelids. I have now to place on record i new appearance, which is, I think, very aptly expressed by term "hare-lip." The worm which I have had under ination presented the peculiarity figured below, and whetat and in motion suggested to my mind most forcibly the ance which we associate with the name I have adopted. The specimen in question belongs to the genus Allolotes in which genus, so far as my experience goes, almost abnormalities are found. The genus Lumbricus, it sh observed, is very seldom, if ever, known to present these peculiarities. Hitherto the Long worm (A. lenga ----pr. ---per 2 Diagram of the anterior portion of green-worm (Allalebophera Savigny), showing abnormal appearance of lip (pr), peristom and three succeeding segments, seen from above, and enlarged has been most prolific of bifurcated heads and tails find the Green worm (A. chlorotica, Savigny) yield, features for study. The peculiarities which have p themselves in former times have usually taken the i second head or a supernumerary tail. In this instance no off-growth, however, but merely a malformation anterior segments. One might have supposed that liarity was due to accidental causes. It would have bee to suppose that the head had been split, and then the had healed, leaving a seam down the middle. I however, that each of the three specimens of the Green? which I received from Cork (Ireland) showed some 157 feature, and there were other peculiarities in this p specimen which indicated that we had to deal with a 017 rather than an accidental condition of things. As this is the first occasion on which such a peculiarity has been recorded or figured, I prefer to leave all speculation as to the cause out of the question. We need a good deal more research before we can deal satisfactorily with the biological problems involved in such appearances. As a help towards this, I bring together here a list of all those works which have come under my own and Prof. Andrews's notice, in which abnormalities in annelids are recorded : 1. Andrews: "Proc. U.S. Nat. Mus.," vol. xiv., p. 283, 1891. 2. Andrews: "Amer. Nat.," vol. xxvi., p. 725, 1892. 3. Bell: "Ann. Mag. Nat. Hist.," vol. xvi., p. 475, 1885. 4. Bell: "Proc. Zool. Soc., Lond.," 1887, p. 3. 5. Bonnet: "Euvres d'Hist. Nat. et de Phil.," vol. i., p. 167 seq. 1779. 6. Breese: West Kent Nat. Hist. Soc., 1871. 7. Broome: "Trans. Nat. Hist, Soc." Glasgow, 1888, P. 203. 8. Bülow: "Archiv. f. Naturg," vol. xlix., 1883. 9. Brunette: "Travaux de la Sta. Zool. de Cette," p. 8, Nancy, 1888. 10. Claparède: "Les Chaet. du Golfe de Naples," p. 436, 1868. 11. Fitch: "Eighth Report on Insects of State of New York," appendix, p. 204 seq. Albany, 1865. 12. Foster: Hull Scientific Club, February, 1891. Reported in weekly sup. Leeds Mercury. 13. Friend: "Science Go sip," 1892, pp. 108, 161. 14. Grube: "Archiv. f. Naturg," vol. x., p. 200, 1844. 15. Horst: "Tydsch. ned. Dierk. Veren," 2nd ser., Af. i., p. xxxii, 1882. D.I., 16. Laugerhaus: "Nov. Act., K. L. C. D. Acad.," vol, xiii., p. 102, 1879. 17. Marsh: "Amer. Nat.," vol. xxiv., p. 373. 1890. 18. Macintosh: "Challenger Reports," vol. xii., 1885. 19. Robertson: "Quart. J. Mic. Soc.," vol. xv., p. 157, 1867. 20. Zeppelin: "Zeit. f. Wiss. Zool.," vol. xxxix., p. 615 seq. 1883. 21. Catalogue Terat. Spec. in Mus. Roy. Coll. Surgeons, London, 1872. HILDERIC FRIEND. The Zero Point of Dr. Joule's Thermometer. IN the course of a discussion on "Exact Thermometry" I described (NATURE, vol. xli. p. 488) the results obtained by heating thermometers for a considerable time to 280° and 356°; and pointed out by means of a diagram that at 356°, after about ten hours, the rise of the zero point became-at any rate approximately a rectilinear function of the logarithm of the time; though at 280°, even after more than 300 hours' heating, the rise appeared to be rather more rapid than would correspond to such a simple relation. Dr. Joule observed the rise of the zero point of a thermometer at the ordinary temperature during a course of no less than thirty-eight years (" Scientific Papers," vol. i. p. 558), and it occurred to me that it would be of interest to ascertain the relation to the logarithm of the time in this case also. The following table contains the dates of Dr. Joule's observations; the total number of months from the date when the first reading was taken; the corresponding logarithms; the total rise of the zero point in scale divisions (13 divisions to 1° F.); the total rise calculated from the formula R 6'5 log, t 4'12, where is the time in months; and lastly the differences between the observed and calculated zero points. THE HE total solar eclipse of April 15-16, 1893, is not only one of the longest of the century, but is the last of the century from which we are likely to get any addition to our knowledge of Solar Physics. The longest duration of totality of this eclipse is 4 minutes 46 seconds, and as the path of the moon's shadow lies to a great extent on land, there is a considerable choice of possible stations with long durations of totality. Commencing in the Southern Pacific the line of totality passes in a north-easterly direction and enters Chili at Charañah in 29° southern latitude, crosses the South American continent, and issues at Para Cura, a village near Ceara, at the north-east corner of Brazil, in latitude 3° 40′ south. It crosses the Atlantic at its narrowest part and enters Africa at Point Palmerin, near Joal, almost midway between Bathurst and Dakar, and in latitude 14° north; the shadow finally leaving the earth in the interior of Northern Africa. The eclipse will be observed by several parties of astronomers in Chili, Brazil, and Africa, there being almost absolute certainty of fine weather in Chili and Africa, and a reasonable probability in Brazil. The English arrangements to observe the eclipse have been made by a joint committee of the Royal Society, the Royal Astronomical Society, and the Solar Physics Committee of the Science and Art Department, South Kensington; Dr. A. A. Common, LL.D., F.R.S., undertaking the duties of Secretary. Two expeditions will be sent from England, one to Africa and the other to Brazil, the expenses being defrayed by a grant of £600 from the Royal Society. The African expedition will be in charge of Prof. T. E. Thorpe, and will consist of Prof. Thorpe, Mr. A. Fowler, Mr. Gray, and Sergeant J. Kearney, R.E. The Brazilian expedition will be in charge of Mr. A. Taylor, who will have with him Mr. W. Shackleton. Prof. Thorpe and his party will leave Liverpool by the British and African mail steamer on March 18th, arriving at Bathurst on April 2nd. They will be met at Bathurst by a gunboat kindly placed at the disposal of the expedition by the Admiralty, and will be conveyed at once to Fundium, a station on the Salum River, about sixty miles from Bathurst; this being the station selected by the Committee from the three which were offered by the French Government. The gunboat will remain with the expedition, and the officers and crew will assist in the preparations for and in the actual observations of the eclipse. After the eclipse the party will be taken to Bathurst on the gunboat, and will return to England by a British and African mail steamer, if one is available. From the time-tables of the steamers now published it appears, however, that there will not be any mail steamer available until the end of April, and in this case a cruiser will meet the party at Bathurst and bring them to the Canary Islands or to Gibraltar, from either of which places they will be able to return by mail steamer, arriving in England early in May. The members of the expedition to Brazil will leave Southampton by the Royal Mail steamer on February 23 for Pernambuco, arriving at the latter place on March 12. They will take passage by the local mail steamers to Ceara, at which place they will arrive about March 20. The Brazilian Government are willing to place a war vessel at the disposal of the foreign expeditions to observe the eclipse, and it is hoped the English observers will be able to avail themselves of the privilege thus gracefully offered. The station selected is at Para Cura, on the coast about forty miles west of Ceara, and the party will rely upon obtaining any necessary help from the Brazilian authorities and from local assistants. The observers will return from Pernambuco by the Royal Mail steamer due to leave there on April 22, and expect to be in England on May 5. The objects of the expeditions are (1) To obtain visual photometric measures of the light of the corona. (2) To obtain photographs of the corona with the fourinch lenses of a little over sixty inches focus belonging to Captain Abney, which were successfully used in Egypt (1882), Caroline Island (1883), Granada (1836), and Salut Isles (1889), in order to continue the series. (3) To obtain enlarged photographs of the corona with small photographic action, so as to show details of the structure of the brightest parts, ie. those nearest the sun. (4) To measure the photographic intensity of the light of the corona, by direct comparison with standard intensity scales placed on the margins of the plates used for the negatives to be obtained under sections 2 and 3. (5) To obtain photographs of the spectrum of the corona. These spectra will be obtained on three different plans: (a) With integrating spectroscopes, where no collimator is used and the prism or prisms are placed directly in front of the object glass of the photographic camera. (6) With ordinary slit spectroscopes, the slit being arranged as a radius of the sun. (c) With ordinary slit spectroscopes, the slit being arranged as a tangent to the sun's limb. The first of these objects will be attempted only at the African station; Prof. Thorpe and his assistant, Mr. Gray, making the observations. Their equipment will consist of a six-inch Simms equatorial of seventy-eight inches focus (lent from Greenwich) fitted with special photometric apparatus lent by Captain Abney. The observations will be made on essentially the same plan as that pursued by Prof. Thorpe at Hog Island, near Granada, in 1886, separate portions of the corona being compared with a standard glow lamp by means of a Bunsen photometer. An integrating box for measuring the total coronal light with as little light from the sky as possible, and an ordinary Bunsen's bar photometer will also be used, these being entrusted to officers of the gunboat. As regards objects 2, 3, and 4, duplicate apparatus has been arranged for use at the two stations. A photoheliograph mounting from Greenwich has been lent for Brazil, and an exactly similar instrument from South Kensington for Africa. On each of these mountings a specially designed new double tube will be fixed. An Abney lens will be mounted in one compartment of each of these tubes, and this, with a focal length of sixty inches, will give pictures on the scale of rather more than half an inch to the moon's diameter. In the other compartment a four-inch Dallmeyer photoheliograph lens will be mounted in combination with a specially-constructed two-and-a-half-inch Dallmeyer negative lens of eight inches negative focus; this arrangement giving, with a total length of sixty-eight inches, pictures on the scale of over one-and-a-half inches to the moon's diameter. This latter arrangement is essentially the same as that of Dallmeyer's new telephotographic lens. It will be so arranged that the ratio between the photographic effect of the Abney lens and the new combination will be as 10: 1. Special plate holders have been made to fit the double tubes, each of these plate holders carrying two plates, | which will be exposed simultaneously to the ima formed by the Abney lens and the enlarging combinat The six separate exposures, giving twelve photograp will be so arranged that the longest exposed pictures the enlarging combination will have received the sa photographic action as the shortest exposed pictures the Abney lens. The whole of the pictures wit form a continuous series, all the short exposures in th series having a direct enlargement of three diameters In Brazil Mr. Taylor will take charge of this doit instrument, and in Africa the similar instrument wil entrusted to Sergeant Kearney. On the night before eclipse intensity scales for object 4 will be impresse the use of standard lights and specially-constructed sa kindly supplied by Captain Abney on all the plates to le exposed to the corona. The plates will be developed are stations as soon as convenient after the eclipse, experien on previous occasions, both by English and America observers, having shown that it is impossible to rep undeveloped plates after exposure in the tropics, .. bring them home without serious deterioration. Similar spectroscopic work is to be carried out at two stations. For the integrating spectroscope in Af Mr. Fowler will use a six-inch objective prism with a inch photographic lens of about nine-feet focus, mounted an equatorial stand, belonging to Prof. J. Norman Locke and kindly lent for the expedition. At the Bra station Mr. Shackleton will use two three-inch prisos front of a three-inch photographic lens of about twee focus; the spectroscope, which belongs to South Kenst ton, being arranged horizontally and used with a tec heliostat, also lent by the Science and Art Departa: Very short exposures will be given at each station as commencement and end of totality, so as to obta possible, the very numerous bright lines which have b observed in the chromosphere; and exposures of 5 to 45 seconds will be given during totality. In Africa the radial and tangential slit spectros will be mounted together on the Corbett equa stand lent from Greenwich, the spectroscopes belonging to the Royal Society. Mr. Fowler Sergeant Kearney will erect and adjust these ments, but the actual exposure, which will extend ta the whole of totality, will be made by an officer gunboat who will be placed in charge of the instrume In Brazil the radial and tangential slit spectroscope be mounted horizontally and used with a second te heliostat lent by the Science and Art Department erection and adjustment will be made by the obser but the actual exposure during totality will be ent to a local assistant. Orthochromatic plates will be for all the spectroscopic work, the spectra ob extending from above D into the ultra-violet. Briefly summarised, the English programme > follows: In Africa :-Prof. T. E. Thorpe, assisted by M and local assistance-Photometric measures of visual intensity of the corona with the equatorial meter, the integrating photometer, and the bar meter; Mr. Fowler-The six-inch integrating scope; Sergeant Kearney-the Abney and Da coronographs; local assistance the radial and tial slit spectroscopes. In Brazil:-Mr. Taylor, the Abney and Da coronographs; Mr. Shackleton, the three-inch tw integrating spectroscope; local assistance, the rad tangential slit spectroscopes. It is not yet decided whether one of the 20-inch of 45-inches focus specially constructed to phy the faint extensions of the corona during the ecli 1889 (December 21-22) will be taken to Africk so it will be entrusted to a local assistant originally intended to use one of these in Africa. was hoped that one would be used by the Harvard Observatory party, which is to occupy a station in Chili, but Prof. W. H. Pickering writes that difficulties of transport will prevent him from taking the 20-inch mirror he has at Arequipa to the Harvard station; and owing to this and to the already large programme of the English party in Africa there is some doubt whether they will take one of the mirrors. April being the middle of the rainy season in Brazil, it is not deemed advisable to send one of the mirrors to that station. The duration of totality at Para Cura is four minutes forty-four seconds, the altitude of the sun being between 70 and 80. At Fundium the totality lasts four minutes eight seconds, the altitude of the sun being about 54°. The Joint Eclipse Committee having arranged the expeditions and the general scheme of work, final details as to the actual operations have been left to a sub-committee consisting of the Astronomer Royal, Captain Abney, Mr. H. H. Turner, Prof. Thorpe, Mr. A. Taylor, and the secretary, Dr. Common. Prof. Lockyer, previous to leaving England for Egypt, determined the exposures to be given by Messrs. Fowler and Shackleton with the integrating spectroscopes. These, with the final instructions to observers drafted by the sub-committee, will be published in due course. At present very few details are available as to the actual work to be undertaken by foreign observers. The Harvard College Observatory expedition to Chili has already been mentioned. Prof. Schaeberle, of the Lick Observatory, has already started for Chili, and will use a six-and-a-half-inch equatorial, a five-inch horizontal photoheliograph of forty-feet focus, and a Dallmeyer portrait lens. He will be assisted by Mr. Gale, an amateur, from Paddington, N.S.W. A Chilian party will also observe the eclipse in Chili. At Para Cura there will probably be two or three American parties, one being announced as probably under Prof. H. S. Pritchett, from Washington University, St. Louis, and another will probably be brought to that station by Prof. David P. Todd. A Brazilian party will also observe. The Bureau des Longitudes, Paris, are sending a complete expedition to Joal, in Africa, under MM. Deslandres and Bigourdan, the latter observer having already started for his station. The work undertaken will be to obtain photographs of the corona and of its spectrum. M. de la Baume Pluvinel will also go to Joal to photograph the corona. At present we have not heard of any Italian expedition, but it is hoped that Prof. Tacchini will be able to arrange to observe the eclipse. A. TAYLOR. MEASURE OF THE IMAGINATION THE first perceptible sensation is seldom due to a solitary stimulus. Internal causes of stimulation are in continual activity, whose effects are usually too faint to be perceived by themselves, but they may combine with minute external stimuli, and so produce a sensation which neither of them could have done singly. I desire now to draw attention to another concurring cause which has hitherto been unduly overlooked, or only partially allowed for under the titles of expectation and attention. I mean the Imagination, believing that it should be frankly recognised as a frequent factor in the production of a just perceptible sensation. Let us reflect for a moment on the frequency with which the imagination produces effects that actually overpass the threshold of consciousness, and give rise to what is indistinguishable from, and mistaken for a real sensation. Every one has observed instances of it in his own person Extract from a lecture on "The Just-Perceptible Difference," delivered before the Royal Institution, on Friday, January 27, by Francis Galton, F.R.S. We hope to give next week an extract on "Optical Continuity." and in those of others. Illustrations are almost needless; I may, however, mention one as a reminder; it was current in my boyhood, and the incident probably took place not many yards from where I now stand. Sir Humphrey Davy had recently discovered the metal potassium, and showed specimens of it to the greedy gaze of a philosophical friend as it lay immersed in a dish of alcohol to shield it from the air, explaining its chemical claim to be considered a metal. All the known metals at that time were of such high specific gravity that weight was commonly considered to be a peculiar characteristic of metals potassium, however, is lighter than water. The philosopher not being aware of this, but convinced as to its metallic nature by the reasoning of Sir Humphrey, fished a piece out of the alcohol, and, weighing it a while between his finger and thumb, said seriously, as in further confirmation, "How heavy it is!" ; In childhood the imagination is peculiarly vivid and notoriously leads to mistakes, but the discipline of after life is steadily directed to checking its vagaries and to establishing a clear distinction between fancy and fact. Nevertheless, the force of the imagination may endure with extraordinary power and be cherished by persons of poetic temperament, on which point the experiences of our two latest Poet-Laureats, Wordsworth and Tennyson, is extremely instructive. Wordsworth's famous "Ode to Immortality " contains three lines which long puzzled his readers. They occur after his grand description of the glorious imagery of childhood, and the "perpetual benediction" of its memories, when he suddenly breaks off into-- "Not for these I raise The song of thanks and praise, Fallings, from us, vanishings," &c. Why, it was asked, should any sane person be "obstinately" disposed to question the testimony of his senses, and be peculiarly thankful that he had the power to do so? What was meant by the "fallings off and vanishings," for which he raises his "song of thanks and praise"? The explanation is now to be found in a note by Wordsworth himself, prefixed to the ode in Knight's edition. Wordsworth there writes, "I was often unable to think of external things as having external existence, and I communed with all I saw as something not apart from, but inherent in, my own immaterial nature. Many times while going to school have I grasped at a wall or tree to recal myself from this abyss of idealism to the reality. At that time I was afraid of such processes. In later times I have deplored, as we all have reason to do, a subjugation of an opposite character, and have rejoiced over the remembrances, as is expressed in the lines Obstinate questionings,' &c." He then gives those I have just quoted. idea is found in the verses of the successor of WordsIt is a remarkable coincidence that a closely similar worth, namely, the great poet whose recent loss is mourned by all English-speaking nations, and that a closely similar explanation exists with respect to them. Percivale, then a monk, recounts to a brother monk the For in Lord Tennyson's 66 Holy Grail" the aged Sir following words of King Arthur: "Let visions of the night or of the day Come, as they will; and many a time they come Sir Percivale concludes just as Wordsworth's admirers formerly had done: "I knew not all he meant." Now, in the Nineteenth Century of the present month 1 Knight's edition of Wordsworth, vol. iv. p. 47. Mr. Knowles, in his article entitled "Aspects of Tennyson," mentions a conversational incident curiously parallel to Wordsworth's own remarks about himself:"He [Tennyson] said to me one day, 'Sometimes as I sit alone in this great room I get carried away, out of sense and body, and rapt into mere existence, till the accidental touch or movement of one of my own fingers is like a great shock and blow, and brings the body back with a terrible start." Considering how often the imagination is sufficiently intense to stimulate a real sensation, a vastly greater number of cases must exist in which it excites the physiological centres in too feeble a degree for their response to reach to the level of consciousness. So that if the imagination has been anyhow set into motion, it shall as a rule originate what may be termed incomplete sensations, and whenever one of these concurs with a real sensation of the same kind, it would swell its volume. This supposition admits of being submitted to experiment by comparing the amount of stimulus required to produce a just perceptible sensation, under the two conditions of the imagination being either excited or passive. Several conditions have to be observed in designing suitable experiments. The imagined sensation and the real sensation must be of the same quality; an expected scream and an actual groan could not reinforce one another. Again, the place where the image is localised in the theatre of the imagination must be the same as it is in the real sensation. This condition requires to be more carefully attended to in respect to the visual imagination than to that of the other senses, because the theatre of the visual imagination is described by most persons, though not by all, as internal, whereas the theatre of actual vision is external. The important part played by points of reference in visual illusions is to be explained by the aid they afford in compelling the imaginary figures to externalise themselves, superimposing them on fragments of a reality. The visualisation and the actual vision fuse together in some parts, and supplement each other elsewhere. The theatre of audition is by no means so purely external as that of sight. Certain persuasive tones of voice sink deeply, as it were, into the mind, and even simulate our own original sentiments. The power of localising external sounds, which is almost absent in those who are deaf with one ear, is very imperfect generally, otherwise the illusions of the ventriloquist would be impossible. There was an account in the newspapers a few weeks ago of an Austrian lady of rank who purchased a parrot at a high price, as being able to repeat the Paternoster in seven different languages. She took the bird home, but it was mute. At last it was discovered that the apparent performances of the parrot had been due to the ventriloquism of the dealer. An analogous trick upon the sight could not be performed by a conjuror. Thus he could never make his audience believe that the floor of the room was the ceiling. As regards the other senses the theatre of the imagination coincides fairly well with that of the sensations. It is so with taste and smell, also with touch, in so far that an imagined impression or pain is always located in some particular part of the body, then if it be localised in the same place as a real pain, it must coalesce with it. Finally, it is of high importance to success in experiments on Imagination that the object and its associated imagery should be so habitually connected that a critical attitude of the mind shall not easily separate them. Suppose an apparatus arranged to associate the waxing and waning of a light with the rising and falling of a sound, holding means in reserve for privately modifying the illumination at the will of the experimenter, in order that the waxing and waning may be lessened, abolished, or even reversed. It is quite possible that a person who had no idea of the purport of the experiment might be deceived, and be led by his imagination to declare that the light still wa and waned in unison with the sound after its ups in downs had been reduced to zero. But if the subje the experiment suspected its object he would be thro into a critical mood; his mind would stiffen itself, as were, and he will be difficult to deceive. Having made these preliminary remarks, I will ment one only of some experiments I have made and making from time to time, to measure the force of my imagination. It happens that although most pers train themselves from childhood upwards to disting imagination from fact, there is at least one instance which we do the exact reverse, namely, in respect t auditory presentation of the words that are perusei the eye. It would be otherwise impossible to realise sonorous flow of the passages, whether in prose or poet that are read only with the eyes. We all of us value cultivate this form of auditory imagination, and it c monly grows into a well-developed faculty. I infer th when we are listening to the words of a reader whe eyes are simultaneously perusing a copy of the bookty which he is reading, that the effects of the aud imagination concur with the actual sound, and proda stronger impression than the latter alone would be a to make. I have very frequently experimented on myself a success, with the view of analysing this concurren pression into its constituents, being aided there two helpful conditions, the one is a degree of dea which prevents me when sitting on a seat in the m rows from following memoirs that are read in t suitable to the audience at large; and the is the accident of belonging to societies in unrevised copies of the memoirs, that are ab be read, and usually in monotones, are obtain in order to be perused simultaneously by the Now it sometimes happens that portions of these pap however valuable they may be in themselves, du interest me, in which case it has been a neversource of diversion to compare my capabilities of f ing the reader when I am using my eyes, and when not. The result depends somewhat on the quality voice; if it is a familiar tone I can imagine what is c much more accurately than otherwise. It depends a on the phraseology, familiar words being vividly sented. Something also depends on the mood st time, for imagination is powerfully affected by all of emotion. The result is that I frequently find my a position in which I hear every word distinctly so they accord with those I am perusing, but whenever i is changed, although the change is perceived, the word is not recognised. Then, should I raise me from the copy, nothing whatever of the reading understood, the overtones by which words distinguished being too faint to be heard a rule, I estimate that I have to app the reader by about a quarter of the p distance, before I can distinguish his words by t alone. Accepting this rough estimate for the p of present calculation, it follows that the potency hearing alone is to that of my hearing plus imag as the loudress of the same overtones heard at 4 units of distance respectively; that is as about or as 9 to 16. Consequently the potency of my a imagination is to that of a just perceptible sound 25 or as 7 units, to 16. So the effect of the imagin this case reaches nearly half-way to the level of conse ness. If it were a little more than twice as st would be able by itself to produce an effect indist able from a real sound. Two copies of the same newspaper afford easily sible materials for making this experiment, a few having been altered here and there in the copy to from. |