that there is only one obvious mistake in the whole work, and the general correctness of declamation is higher than in most of his German works. This is typical-of Weber's general culture, mental energy and determination; points in which, as in many traits in his music, he strikingly resembles Wagner. But all his determination could not quite repair the defects of his purely musical training, and though his weaknesses are not of glaring effect in opera, still there are moments when even the stage cannot explain them away. Thus the finale of Der Freischütz breaks down so obviously that no one thinks of it as anything but a perfunctory winding-up of the story, though it really might have made quite a fine subject for musical treatment. In Euryanthe Weber attained his full power, and his inspiration did not leave him in the lurch where this work needed large musical designs. But the libretto was full of absurdities; especially in the last act, which not even nine remodellings under Weber's direction could redeem. Yet it is easy to see why it fascinated him, for, whatever may be said against it from the standpoints of probability and literary merit, its emotional contrasts are highly musical. Indeed it is through them that the defects invite criticism.
Oberon is spoilt by the old local tradition of English opera according to which its libretto admitted of no music during the action of the drama. Thus Weber had in it no opportunity for his musical stage-craft; apart from the fact that the action itself is entirely without dramatic motive and passion, since the characters are simply shifted from Bordeaux to Bagdad whenever Oberon waves his wand.
Many attempts have been made to improve the libretti of Euryanthe and Oberon, but none are quite successful, for Weber has taken a great artist's pains in making the best of bad material. All that can be said against Weber's achievements only reveals the more emphatically how noble and how complete in essentials was his success and his claim to immortality. His pianoforte works, while showing his helplessness in purely musical form, more than bear out his contemporary reputation as a very great pianoforte player. They have a pronounced theatrical tendency which, in the case of such pieces of gay romanticism as the Invitation à la danse and the Concertstück, is amusing and by no means inartistic. In orchestration Weber is one of the greatest masters. His treatment of the voice is bold and interesting, but very rash; and his declamation of words is often incorrect. His influence on the music of his own day is comparable to his influence on posterity; for he was not only a most efficient director but a very persuasive journalist; and (in spite of the inexperience that made him disapprove of Beethoven) for all good music other than his own he showed a growing enthusiasm that was infectious.
WEBER, WILHELM EDUARD (1804-1891), German physicist,
was born at Wittenberg on the 24th of October 1804, and was
a younger brother of Ernst Heinrich Weber, the author of Weber's
Law (see below). He studied at the university of Halle, where
he took his doctor's degree in 1826 and became extraordinary
professor of physics in 1828. Three years later he removed to
Göttingen as professor of physics, and remained there till 1837,
when he was one of the seven professors who were expelled from
their chairs for protesting against the action of the king of
Hanover (duke of Cumberland) in suspending the constitution.
A period of retirement followed this episode, but in 1843 he
accepted the chair of physics at Leipzig, and six years later
returned to Göttingen, where he died on the 23rd of June 1891.
Weber's name is especially known for his work on electrical
measurement. Until his time there was no established system
either of stating or measuring electrical quantities; but he showed,
as his colleague K. F. Gauss did for magnetic quantities, that
it is both theoretically and practically possible to define them,
not merely by reference to other arbitrary quantities of the same
kind, but absolutely in terms in which the units of length,
time, and mass are alone involved. He also carried on extensive
researches in the theory of magnetism; and it is interesting that
in connexion with his observations in terrestrial magnetism he
not only employed an early form of mirror galvanometer, but
also, about 1833, devised a system of electromagnetic telegraphy,
by which a distance of some 9000 ft. was worked over. In
conjunction with his elder brother he published in 1825 a
well-known treatise on waves, Die Wellenlehre auf Experimente gegründet; and in 1833 he collaborated with his younger brother, the physiologist Eduard Friedrich Weber (1806-1871), in an investigation into the mechanism of walking.
WEBER'S LAW, in psychology, the name given to a principle
first enunciated by the German scientist, Ernst Heinrich Weber
(1795-1878), who became professor at Leipzig (of anatomy,
1818, of physiology, 1840). He was specially famous for his
researches into aural and cutaneous sensations. His law, the
purport of which is that the increase of stimulus necessary to
produce an increase of sensation in any sense is not a fixed
quantity but depends on the proportion which the increase
bears to the immediately preceding stimulus, is the principal
generalization of that branch of scientific investigation which
has come to be known as psycho-physics (q.v.).
According to Gustav Fechner (q.v.), who has done most to prosecute these inquiries and to consolidate them under a separate name, “psycho-physics is an exact doctrine of the relation of function or dependence between body and soul.” In other words, it is throughout an attempt to submit to definite measurement the relation of physical stimuli to the resulting psychical or mental facts, and forms an important department of experimental psychology. It deals with the quantitative aspects of mental facts — their intensity or quantity proper and their duration. Physical science enables us, at least in the case of some of the senses, to measure with accuracy the objective amount of the stimulus, and introspection enables us to state the nature of the subjective resujt. Thus we are able to say whether a stimulus produces any psychical result, and can fix in that way the minimum sensibile or “threshold of consciousness” for each of the senses. In like manner (though with less accuracy, owing to the disturbing nature of the conditions) we can fix the sensational maximum, or upper limit of sensibility, in the different senses, that is to say, the point beyond which no increase of stimulus produces any appreciable increase of sensation. We thus determine, as Wundt puts it, the limit-values between which changes of intensity in the stimulus are accompanied by changes in sensation. But the central inquiry of psycho-physics remains behind. Between the quantitative minimum and the quantitative maximum thus fixed can we discover any definite relation betwee.n changes in the objective intensity of the stimuli and changes in the intensity of the sensations as estimated by consciousness. The answer of psycho-physics to this inquiry is given in the generalization variously known as “Weber's law,” “Fechner's law,” or the “psycho-physical law,” which professes to formulate with exactitude the relations which exist between change of stimulus and change of sensation.
As we have no means of subjectively measuring the absolute intensity of our sensations, it is necessary to depend upon the mental estimate or comparison of two or more sensations. Comparison enables us to say whether they are equal in intensity, or if unequal which is the greater and which is the less. But as they approach equality in this respect it becomes more and more difficult to detect the difference. By a series of experiments, therefore, it will be possible, in the case of any particular individual, to determine the least observable difference in intensity between two sensations of any particular sense. This least observable difference is called by Fechner the Unterschiedsschwelle or “difference-threshold,” that is to say, the limit of the discriminative sensibility of the sense in question. That such a “threshold,” or least observable difference, exists is plain from very simple examples. Very small increases may be made in the objective amount of light, sound or pressure — that is, in the physical stimuli applied to these senses — without the subject on whom the experiment is made detecting any change. It is further evident that, by means of this Unterschiedsschwelle, it is possible to compare the discriminative sensibility of different individuals, or of different senses, or (as in the case of the skin) of different parts of the same sense organ: the smaller the difference observable the finer the discriminative sensibility. Thus the discrimination of the muscular sense is much more delicate than that of the sense of touch or pressure, and the discriminative sensibility of the skin and the retina varies very much according to the parts of the surface affected. Various methods have been adopted with a view to determine these minima of discriminative sensibility with an approach to scientific precision. The first is that employed by Weber himself, and has been named the method of just observable differences. It consists either in gradually adding to a given stimulus small amounts which at first cause no perceptible difference in sensation but at a certain point do cause a difference to emerge in consciousness, or, vice versa, in gradually decreasing the amount of additional stimulus, till the difference originally perceived becomes imperceptible. By taking the average of a number of such results, the minimum may be determined with tolerable accuracy. The second method is called by Fechner the method of correct and incorrect instances. When two stimuli are
