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Davis, M.D. Ripon Rev. H. P. Hamilton, M.A., F.R.S. and G.S. Rev. P. Ewart, M.A. Ruthin-Rev. the Warden of Humphreys Jones, Esq. Ryde, I. of Wight-Sir Rd. Simeon, Bt. Sheffield-J. H. Abrahams, Esq. Shepton Mallet-G. F. Burroughs, Esq. William M. Manning, Esq. J. E. Bowman, Esq., F.L.S., Treasurer Dawson Turner, Esq. THOMAS COATES, Esq., Secretary, No. 59, Lincoln's Inn Fields. London: Printed by WILLIAM CLOWES and SONS, Stamford Street, THE PENNY CYCLOPÆDIA OF THE SOCIETY FOR THE DIFFUSION OF USEFUL KNOWLEDGE. nd wept anie INT INTESTINES are that portion of the digestive canal into which the food is received after it has been partially digested in the stomach, and in which its further assimilation, the separation and absorption of the nutritive matter, and the removal of that which is excrementitious, take place. In an adult, the intestines consist of a convoluted tube of from 30 to 40 feet in length, and are, from the difference of their diameters in different parts, divided into small intestines, which comprise about the first four-fifths, and large intestines, which constitute the other fifth of their length. The former again are divided into the duodenum, into which the ducts from the liver and pancreas open, and in which the chyme from the stomach is converted into chyle [DIGESTION; CHYLE]; the jejunum, in which the absorption of the nutritive matter of the food is principally effected; and the ileum. The large intestines are divided into the cœcum, colon, and rectum. The walls of the intestinal canal are composed of three principal coats or membranes. The exterior, which is smooth and polished, is called the peritoneal, and its principal use is to permit the free motions of the intestines within the abdomen, and of their several convolutions against each other, by rendering the effect of friction as slight as possible. Next to and within the peritoneal coat is the muscular, which is composed of two layers of fibres; an external, in which they are directed longitudinally, and an internal, of which the fibres encircle the intestine. By these the motions of the intestines and the propulsion of their contents are effected; the longitudinal fibres tending to shorten each portion of the canal, while the circular contract its diameter; and the two sets together producing a motion of the tube somewhat like that of a worm, whence it has received the name of vermicular motion. Beneath these layers, and separated from them by a stratum of cellular tissue, which has been sometimes called the fourth or nervous coat, is the mucous membrane, which is the most important part of the intestinal canal. It is everywhere beset by innumerable minute glands, by which the secretion of mucus and the other intestinal juices is carried on. In the small intestines it has a fine velvet-like surface, made up of minute thickly-set hair-like processes, or villi, which are about 4th of an inch in length, and stand up so that their tops seem to form a smooth surface like the pile of velvet. These, as well as all the rest of the mucous membrane, are protected from the irritation which the immediate contact of foreign substances would produce, by a covering of an inorganic cuticle of extreme delicacy, called epithelium. The principal functions performed by the intestines are the conversion of the chyme [DIGESTION; GASTRIC JUICE] into chyle, the absorption of the latter, and the removal of the innutritious parts of the food and of a considerable quantity of excrementitious matter. In the first process, which constitutes the last stage of digestion, the secretions of the liver and pancreas take an important part: the P. C., No. 788. INT ducts by which they are conveyed open into the intestinal canal, near the middle of the duodenum, or about six inches from the aperture by which the food passes from the stomach; and immediately beyond the orifices of these ducts the villi are of great size, and thickly set on prominent folds of the mucous membrane, called valvula conniventes. These folds, at the same time that they increase the extent of surface for absorption, serve to entangle the semifluid mass of food, now completely digested; they are most numerous and prominent in the jejunum, where absorption is carried on earliest and most rapidly, but are found to a slighter extent throughout the whole of the small intestines. The absorption of the chyle is effected by the villi, each of which is composed of a minute tube, which is the termination of a branch of the lacteal or absorbent system of vessels, and is ensheathed in a delicate tissue containing a net-work of capillary arteries and veins. The form and function of the villi may be best demonstrated in an animal which has died suddenly after a full meal; they then appear turgid, and stand erect, filled with a whitish milky fluid, the chyle, which, as fast as it is absorbed by them, is conveyed by numerous converging streams into the main trunk of the absorbent system, called the thoracic duct, through which it is gradually poured into the blood of the left subclavian vein, at a short distance before it enters the right side of the heart. [HEART.] The whole process of absorption is not unaptly compared to that by which the fluids are conveyed from the earth through the roots into the stem of a plant; the villi of the intestine being represented by the tufts of hair-like spongioles which are placed at the terminations of the fibres of the root. The portion of the food which is unfit for the nourishment of the body is forced onwards by the vermicular motion of the intestines, and being mixed with the resinous and other excrementitious substances secreted by the liver and other glands, is conveyed through the whole tract of the intestines; and after it has been exposed to the absorbing vessels, which are placed in greater or less abundance in every part of the canal, so that not a particle of nutriment can be lost, the residue is voided. INTONATION, in vocal music, is the tuning of the voice-the singing true or false-in tune or out of tune. Correct Intonation is the first requisite in a singer; this wanting, all his other musical qualities, however good, are unavailing. INTRA'DOS and EXTRA'DOS, the lower and higher curves of an arch. [ARCH.] INTRICAʼRIA, a small Polypifer from the oolitic rocks of France, allied to Cellaria. (M. Defrance, Dic. des Sci. Nat.) INULIN, a peculiar vegetable substance which is spon taneously deposited from a decoction of the roots of the Inula Helenium. It is a white powder, like starch, is insoluble in cold and soluble in hot water, from which it is deposited on cooling, and this distinguishes it from starch. With iodine it gives a greenish-yellow compound, which is not permanent. Inulin is distinguished from gum by its insolubility in cold water, and by not giving saccholactic acid when digested in nitric acid. , and therefore cannot require a greater. For a man t conceive of a greater certainty than that any idea us mind is such as he perceives it to be, and that two eas, wherein he perceives a difference, are different and not precisely the same.' His definition, or rather explanation, of intuition is as follows:-'Sometimes the mind perceives the agreement or disagreement of two ideas immediately by themselves, and this, I think, we may call intuitive knowledge. In this the mind is at no pains of proving or examining, but perceives the truth as the eye does the INVARIABLE (Mathematics), the same word in meanlight, only by being directed to it.' (Essay on Human Un- ing as CONSTANT, which see. There are however two sorts derstanding, b. iv., c. ii., §1.) Campbell's definition is of constants, which it is desirable to treat under different similar having defined truth to be the conformity of our names: the first, which we may call a constant, or a comconceptions to their antetypes in the nature of things, he mon constant, meaning a quantity which is absolutely indeclares intuitive truth to be that which is perceived imme-variable; the second meaning a function which may vary, diately on a bare attention to the ideas under review. but which does not vary in the processes required by a given equation. This we propose to call the invariable function of that equation, or its invariable. The nature of the relation which subsists between intuition and reasoning has been strongly contested. While Beattie maintains that the connexion between them, how Thus, in a common differential equation, which is supclosely soever they are found in general to be connected, is posed to be true of y and x when passes through all not necessary, but, on the contrary, a being endued with stages of magnitude whatsoever, the only invariable is an one may be destitute of the other; Dugald Stewart, on absolute invariable, or a common constant. But in an the other hand, insists that the two are not radically distinct, equation of differences, in which only passes from one although by most writers they are considered to be different whole number to another, the invariable function is any faculties. Locke having rightly maintained that every one which remains unaltered by changing from one step which the reason makes in demonstrative knowledge whole number to another. Thus, [INTEGRATION, FINITE] has intuitive certainty, and that consequently the power of instead of saying that the solution of ▲y = x + 1 is reasoning presupposes that of intuition, Stewart thinks(+x) + C, where C is a constant, we may allow C to that the intuition of Locke implies the power of reasoning; be any function of x, which is unaltered by changing a or, at least, that intuition combined with memory explains from one whole number to another. Such a function is reasoning. Here his usual sagacity appears to have failed (cos. 2x), so that the solution is(x2+x) + (cos. 2πx), Stewart. While the mind itself is perfectly simple, it and the last term is the invariable of the equation. has been, for the purpose of attaining accuracy of language Again, suppose it required to solve the functional equaand distinctness of theory, supposed to be multiple; and tion (x2)=2 px. One solution of this is a clog x, distinct faculties have been ascribed to it according as its where c is any absolute constant. But the equation is several operations comprise more or fewer elements. Ac. solved if c be a function of x, provided it be one which does cording therefore to his own account, reason, which involves not change when x is changed into x. Such a function is the element of time, must be kept distinct from intuition, log. log r which does not involve that element. log 2 The proper objects of intuitive certainty are identical propositions. This of course does not mean propositions verbally identical; such as 'a man is a man.' But while the object of thought is perfectly and always one, it may present itself to the thought under a variety of aspects, either dissolved into its elements or as combined into a whole. It is this identity under an apparent diversity that constitutes that original and primary evidence which makes certain propositions, as soon as the respective terms are understood, to be perceived intuitively. On the other hand, the apparent identity of a real diversity is the ground of all sophistical argument. The ultimate form of legitimate argumentation is, a = b, b = c, .' . a = c. But every fallacy, when detected, will invariably be found to be a b±r, b = c, ... a = c. The sophistry consists in the suppression of the element r, either positive or negative. In the philosophy of Kant the term intuition (anschauung) is used to denote the single act of the sense upon outward objects according to its own laws. It appears to be employed in a like sense in the following extract from Glanvil-Some say that the soul is not passive under the material phantasms; but doth only intuitively view them by the necessity of its own nature, and so observes other things in these their representatives.' (Vanity of Dogmatising, c. iv., p. 29.) COS. { 2T or x = any function of cos. or any function of it, General methods of finding invariable functions, as far as they have yet been given, will be found in the Encyclopædia Metropolitana,' article Calculus of Functions.' INVENTION. This term, when used in the language of art, has a different signification from what it usually bears in common language. It does not mean discovery, but combines conception, or the peculiar way in which an artist's mind takes cognizance of a subject to be represented, with the mode of treatment, or choice of objects and manner of disposing them best adapted for producing a desired effect. Thus, in painting and sculpture, it is the faculty by which the most perfect mode of illustration, by colour or by form, is suggested to the artist, and by which the mind of the spectator is led to comprehend the truth, the intention, and the whole purpose of the work before him; but so distinct is it at the same time from perfect execution, that it is often found to exist independently of excellence in that particular, some of the finest inventions in art being manifestly defective in technical requirements. It is therefore the highest quality in the constitution of the artist's mind; as Opie says, Destitute of invention, a poet is but a plagiary, and a painter a copier of others.' (Lectures on Painting.) It is hardly necessary to enter into the question whether the power of invention be a primary and original law of the mind, or whether the effect of cultivation. Some have be I'NULA, a genus of composite plants, one of whose species, I. Helenium, is used medicinally. This plant is a native of various parts of Europe, in pastures and woods; it has a thick bitter mucilaginous root, a stout stem three feet high, broad ovate serrated leaves, and large yellow flower-lieved it may be a result of acquirements begun in youth, heads, which are solitary at the end of the ramifications. I'NULA HELENIUM (Elecampane), an indigenous perennial herbaceous plant, found in moist meadows, the root of which is used in medicine. This part is thick and branching, brown externally, white internally, with an aromatic odour and a mucilaginous taste, at first bitter, afterwards sharp and camphor-like. In addition to mucilage and a large quantity of a variety of starch termed inulin, it contains a crystallized volatile oil (stearopten), a bitter extractive, an acrid resin, and some salts of lime, &c. and carried on till the power is developed and perfected; others conceive that it is unatatinable by any human effort, and is part of the original constitution of the mind. But even admitting invention to be a gift of nature, and not reducible to rule, nor to be taught by any regular process, it still may be improved by study. Whatever natural disposition or original capacity may exist-and it will not, we suppose, be denied that some minds are more bountifully endowed than others--every power short of creation must have groundwork and foundation on which and out of These ingredients give it a tonic and stimulating pro- which to exercise itself; and even the inventive faculty, perty, and it is employed in debility of the stomach, and which seems to approach nearest to creation, depends upon other diseases of mucous surfaces unattended with inflam-knowledge, by whatever means acquired, for materials with mation. It is however not much used, which to develop and declare itself. Sir Joshua Reynolds (Discourses) says, 'He who has the most materials has the greatest means of invention, and if he has not the power of using them, it must be from a feebleness of intellect;' and it is in vain to endeavour to invent without materials on which the mind may work,' &c. tions of artists, and discriminate between the dept vated and original minds and the commonplace peranie of mere mechanical copiers. Invention is required le mbranch of art to raise it above tameness and insipidity: i indeed the magic power by which works of art first attract and then fix the attention. It is hardly necessary to observe, that, difficult as it may be to prescribe bounds to the imagination or the power of invention, it has in art certain and defined limits beyond which the painter and sculptor should not attempt to venture. When the artist dashes into extravagance, defies or outrages nature, and, with a view of exciting wonder, steps out of the region of what is, has been, or may be, he only shows that he has been gifted with fancy, but that it is wild and ill-regulated; he may awaken surprise, and may mistake it for admiration, but he will produce no lasting nor beneficial impression, and his undisciplined fantasy will never deserve to be ranked with the genius that has nobly illustrated nature by the only just, safe, and legitimate means, namely, her own beautiful, and expressive, and perfect works. INVENTORY. [EXECUTOR.] Raffaelle, by the wonderful ability and power which he has shown in choosing subjects in which the greatest quantity of matter or incident could be introduced, and then in representing them at the most critical moment for illustration, in combining all the most striking and affecting circumstances, and filling the spectator's mind with the whole story, by bringing before him, as it were, the past, the present, and even suggesting that which is to follow, may justly be considered the greatest master in invention. He was gifted, if any man ever was, with the fullest portion of natural and inherent genius, but he attained his eminence by the most persevering course of exercise and observation, as the necessary and only means through which the inventive faculty could be manifested. He studied nature diligently and profoundly in all her varieties of beauty and expression. Nothing seems to have escaped him; everything that offered itself out of her great storehouse was treasured as serviceable to his art, and he acquired such an accumulation of materials, INVERARY, a royal burgh and seaport, capital of the serving as handmaids to his invention, that whatever sub-county of Argyle, situated on a small bay at the head of ject came before him found him prepared, and was imme- Loch Fyne, where the river Aray falls into that arm of the diately dignified with all the expression, truth, propriety, sea, 75 miles west by north from Edinburgh. The town nd completeness, if we may use the word, that it was was erected into a royal burgh by charter granted by capable of receiving. Raffaelle never reached the perfect Charles I. and dated 28th January, 1648. (Municipal Cor beauty and character almost superhuman which appear in poration Reports.) The whole territory, with the exception the finest works of the Greeks, nor, in colour, the magic of a small feu, is the property of the Duke of Argyle, of rilliancy and breadth of Titian, another master-spirit; yet, whom the inhabitants hold their houses and grounds either .n the largest and most comprehensive sense of the quality under leases or as tenants at will. It is governed by two we have been describing, he stands (perhaps with one baillies and nine common-councillors. The annual income mighty exception) without an equal or a rival. of the burgh is about 1807. and the annual expenditure is The examples which may be most satisfactorily adduced somewhat less. The town consists chiefly of one row of in illustration of invention in the fine arts, both for their houses facing the bay, built with great uniformity and excellence and for the facility of reference, as we are so covered with slate. The arrangements for watching, cleanfortunate as to possess them in this country, are the Car-ing, lighting, and the supplying of water are confided to the toons of Raffaelle preserved at Hampton Court. Of these town council, and the expenses are defrayed from the prothe Paul preaching at Athens,' 'The Sacrifice at Lystra, ceeds of the burgh manure. The inhabitants are principally and 'The Death of Ananias,' may be selected as the most engaged in the herring-fishery in Loch Fyne, which is said remarkable for the quality we have been considering. to have produced in some seasons upwards of 20,000 barrels. (Beauties of Scotland, vol. v., p. 437.) The grammarschool is superintended by a teacher, whose salary is 207. The number of scholars during the last 10 years has varied from 25 to 30 annually. The population of the burgh and parish in 1831 was 1117. Equally admirable, though totally in a different style, the frescoes of Michael Angelo, in the Sistine Chapel at Rome, must be quoted as triumphs of invention, a proud achievement of the human mind. The comprehensiveness of his scheme of illustration, with the greatness and energetic character of his design and composition, render this one of the finest monuments that art has to boast. In viewing the magnificent works of these two masters, namely, of M. A. Buonarotti, in this chapel, and of Raffaelle d'Urbino, in the loggie and stanze of the same palace (the Vatican), the spectator has a series of examples of as wonderful efforts of inventive genius in historical design as it seems possible to produce. The works of Rubens offer also fine examples of invention, though the quality of his design, or rather of his forms, was not according to a classical or pure standard. It should be observed here that invention is quite independent of the class of design; its force and power may be displayed in every part of the art, and in subjects of inferior grade, or even in the mode of treating colour, light, and shade. Rembrandt, to proceed with further illustration, is one of those who displayed very high powers of invention; ‘a genius,' Fuseli says, of the first class in whatever relates not to form;' and he justly eulogises his 'powers of nature' and 'the grandeur, pathos, and simplicity of his composition.' Thus also, though the quality of his art was not of the highest or grand class, the merit of invention is eminently due to our own Hogarth. Opie, in speaking of this artist, alludes in terms of high admiration to a fine example of invention in one of his pictures of theries called 'The Rake's Progress.' In the bagnio scene he has introduced in the back-ground one of the dissolute women of the party setting fire to a map of the World. We have referred only to a very few out of the numerous artists whose works are worthy of attention as examples of invention; and have confined ourselves to some of the leading painters, though we might easily multiply them from productions in the sister art. Enough however has been said to point out the nature and value of that high quality in design, and to enable the intelligent observer to recognise and appreciate it when he meets it in the produc Inverary Castle, the principal seat of the Duke of Argyle, is situated near the northern extremity of Loch Fyne. It is a quadrangular building, with a tower at each corner, and a high glazed pavilion rising from the centre of the roof. The stone of which it is constructed, though soft, is very durable, and becomes perfectly black when wetted by a shower. The spacious hall, which is hung with arms and other ornaments, is lighted by a lofty window, and surrounded by a gallery. The other apartments are fitted up in a modern style and with good taste. (Parliamentary Papers; Beauties of Scotland, &c.) INVERNESS, a seaport town and royal burgh of some antiquity, the capital of the county of Inverness, and the principal town of the Highlands. It is situated at the southern extremity of the Moray Frith near the eastern entrance of the Caledonian Canal, 155 miles north by west from Edinburgh. The earliest charters upon record are those of King William the Lion, four in number, conferring several privileges upon the burgesses, which were confirmed and extended by the subsequent charters of Alexander II., III., Robert I., David II., James II., Queen Mary, and James VI. The last constitutes the governing charter of the town, and is dated 1st January, 1591. (Municipal Corporation Reports.) The management of the affairs of the burgh is vested in a provost, three baillies, and 15 town councillors. In 1832 the estimated value of the burgh property, consisting principally o lands and other heritable property, was 20,8117.; producing an annual revenue of 22367. The annual expenditure at the same period was 20587., and at Michaelmas 1833 the aggregate debt was 10,614/. The town is large and well built; the houses are lofty, and many of them elegant. The streets have, since 1831, been paved with granite and hard sandstone brought from the banks of Loch Ness. Common sewers have been constructed, and the town is well lighted with gas, and supplied with water by means of pipes from the adjacent river. The system of police is also described |