the effect of a lever increases in proportion to the length of its arm, it is evident that the power of the helmsman to turn the wheel will be increased according to the length of the spokes beyond the circumference of the barrel, so that if the helmsman employs a force of 30 pounds, it will produce an effect of from 90 to 120 pounds upon the tiller (the barrel being one fourth or one fifth of the radius of the spokes), which again forming the long end of a lever 10 or 15 times the length of its shorter arm, the force of the rudder will, by consequence, be from 10 times 90 to 15 times 120, or from 900 to 1800 pounds. When the helm operates by itself, the centre of rotation of the ship and her movements are determined by estimating the force of the rudder by the square of the ship's velocity. When the helm, instead of lying in a right line with the keel, is turned to one side or the other, it receives an immediate shock from the water, which glides along the ship's bottom in running aft, on the side towards which the helm is turned, and pushes it towards the opposite side, whilst it is retained in this position, so that the stern, to which the rudder is confined, receives the same impression, and accordingly turns. in one direction, whilst the head of the ship moves in the opposite. The more the velocity of a ship increases, the more powerful will be the effect of the rudder, because the water will act against it with a force which increases as the square of the swiftness of the fluid, whether the ship advances or retreats. The direction given in the two cases will of course be contrary.

HELMERS, John Frederic, a Dutch poet, born at Amsterdam, in 1767, was destined for commerce, and attended particularly to the study of the modern languages; but the reading of the German, French and English poets soon inspired him with a taste for literature and poetry. Kindled by the classical models of foreign countrics, Helmers composed, in his 19th year, an ode On Night, the beauty of which first revealed his talents. His ode The Poet first established his reputation. From this time, he yielded wholly to the impulse of his genius, and, in 1790, published a larger poem, Socrates, in three cantos, which gave him a high rank among the poets of his nation. But his tragedy, Dinomachus, or the Liberation of Athens, met with but little success on its representation. He afterwards undertook a theatrical journal for dramatic criticism; but his attempt did not receive any encourage

ment from the Dutch public. He afterwards devoted himself to lyric and epic poetry. In 1810, a collection of his poems was published at Amsterdam. His national poem, Holland (in six cantos, Amsterdam, 1812), which was universally admired by his countrymen, soon followed. Helmers died February 26, 1813. The works found among his papers appeared, under the title Nalezing van Gedichten, at Haerlem (2 vols., 1814 and 1815), and, almost at the same time, in another better edition, at Amsterdam.

HELMET; a defensive armor, for the protection of the head, composed of skins of animals, or of metals. Some of Homer's heroes are represented as wearing brazen helmets, with towering crests, adorned with plumes of the tails or manes of horses. Among the Romans, the cassis was a metallic helmet; the galea, a leathern one. (See Lipsius, De Militia Romana, III, 5.) In modern times, they have been of different kinds, some with and others without vizors.

HELMINTHAGOGA; medicines against

worms.

HELMINTHIASIS; the disease which proceeds from intestinal worms.

HELMONT, John Baptist van, born, in 1577, at Brussels, studied natural philosophy, natural history and medicine, in which he made such rapid proficiency, that, in his 17th year, he gave public lectures on surgery at Louvain. The study of the ancients convinced him of the insufficiency of many of their theories on the nature and cure of diseases; in particular, the system of Galen appeared to him to have great defects. He announced, therefore, his intention of making a reform in medicine. But his inability to cure the itch suddenly inspired him with an aversion to medical science, which he declared to be uncertain, and renounced entirely. He left his country, distributed all that he had gained by his practice in medicine, and, for ten years, wandered about the world; when, having become acquainted with an empirical chemist, he entered eagerly upon the study of chemistry. After the example of Paracelsus, he employed himself in seeking a universal remedy by means of that study. His former passion for medicine now revived, but it was a novel kind of medicine, of his own creation. He styled himself medicus per ignem, alluding to the source from which he derived his remedies. He now married, and retired to the little city of Vilvorde, near Brussels. Here he occupied himself till his death with medical

labors, boasted of having found the means of prolonging life, and composed visionary theories on the spiritual and physical formation of man, and on the causes and treatment of diseases. Though chemistry was still in its cradle, yet he made many discoveries, such as the laudanum of Paracelsus, the spirit of hartshorn, the sal volatile, &c. He intended to have overthrown the whole science of medicine, as it was taught in the schools, which he criticised with much justice; but what he produced himself was much more uncertain than all the existing theories. According to him, life is ruled by a principal power, which he called Archæus, the ruler, and by other subordinate powers. The system of Van Helmont resembles that of Paracelsus, yet it is more clear and scientific. Helmont never quitted his laboratory during the thirty years he lived in Vilvorde, yet he asserts that he cured annually more than a thousand men. The emperors Rodolph II, Matthias and Ferdinand II, invited him to Vienna, with promises of wealth and dignities; but he preferred the independence of his laboratory. He died December 30, 1644. Having given his manuscripts, before his death, to his son, with the request that he would publish them if he thought fit, they were printed by Elzevir.

HELMSTADT; a town, with 5200 inhabitants, in the duchy of Brunswick. The university of Julia Carolina, established in 1576 in Helmstädt, was suppressed by Jerome, ex-king of Westphalia, December 10, 1809. The town has a gymnasium, a seminary for the education of teachers, &c., besides manufactories of linen, cotton, flannel, soap, hats, liqueurs and perfumes. In the neighborhood is a mineral spring.

HELOISE, ELOÏse, or Louisa, celebrated for her beauty and wit, but still more on account of her love for Abelard, was born in Paris, in 1101. After her cruel separation from her illustrious lover, she became prioress of the convent of Argenteuil; but she attended more to study than to the monastic discipline of those under her charge, who, finally, were dispersed, in 1129, on account of their licentiousness. She then accepted the invitation of Abelard, and entered, with soine of her nuns, the oratory of Paraclete, where she found ed a new convent. Here she lived in exemplary piety. The bishops loved her as a daughter, the abbots as a sister, and the laity as a mother. Abelard, at her request, wrote the rules for her convent, which were confirmed by pope Innocent

II. She died in 1164. Contemporary writers speak in high terms of the genus of Heloise. She understood Latin, Greek, Hebrew, was familiar with the ancients, and had penetrated the depths of philosophy and theology. Among Abelard's letters, we find three which are ascribed to her, full of fire, genius and imagination. The two first of her letters, which paint the conflict between her present duties and former feelings, and vividly contrast the inward storm of the passions with the repose of the cell, furnished Pope with some of the finest passages of one of his best productions. (See Abelard.)

Ag

But

HELOTS; slaves in Sparta. The name is generally derived from the town of Helos, the inhabitants of which were carried off and reduced to slavery by the Heracli-, dæ, about 1000 B. C. They differed from the other Greek slaves in not belonging individually to separate masters; they were the property of the state, which alone had the disposal of their life and freedom. They formed a separate class of inhabitants, and their condition was, in many respects, similar to that of the boors in some countries of Europe. The state assigned them to certain citizens, by whom they were employed in private labors, though not exclusively, as the state still' exacted certain services from them. riculture and all mechanical arts at Sparta were in the hands of the Helots, since the laws of Lycurgus prohibited the Spartans from all lucrative occupations. the Helots were also obliged to bear arms for the state, in case of necessity. The barbarous treatment to which they were exposed often excited them to insurrection. Their dress, by which they were contemptuously distinguished from the free Spartans, consisted of cat's-skin, and a leather cap, of a peculiar shape. They were sometimes liberated for their services, or for a sum of money. If their numbers increased too much, the young Spartans, it is said, were sent out to assassinate them. These expeditions were called KOUTE; but this account has been disputed. Their number is uncertain, but Thucydides says that it was greater than that of the slaves in any other Grecian state. It has been variously estimated, at from 320,000 to 800,000. They several times rose against their masters, but were always finally reduced.

HELSINGFORS, in the grand-duchy of Finland, on the gulf of Finlard, a seaport and commercial town, with an excellent and strongly-fortified harbor, has manufactories of sail-cloth and linen; popula

tion, 8000. Since the cession of the grand-duchy to Russia, Helsingfors has been made the capital, on account of its commodious situation and its vicinity to Petersburg. October 1, 1819, all the higher offices of the government were transferred hither from Abo. This has promoted the growth of the place. Lat. 60° 10′ N.; lon. 20° 17′ E.

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HELST, Bartholomew van der; painter, born at Haerlem, in 1613. Without having studied the great masters of the Italian school, he attained to a high degree of excellence as a portrait painter. "Before I had seen the works of this painter," says Falconet, "I found it difficult to credit those who thought him superior to Rembrandt, Van Dyke, and similar masters. Since I have examined them closely, I believe that, without prejudice, Helst is, in some respects, superior to those great painters, for his style is more true to nature," &c. All his works show a grand manner; there is nothing frigid nor stiff. His drapery is flowing; his figures well drawn; the accessory parts are closely copied from nature. The year of his death is unknown; it is only certain that he lived in Amsterdam, and that his son was also a good portrait painter.

HELVETIA. Between the Rhone and the Rhine, the Jura and the Rhætian Alps (in the canton of the Grisons), lived the Helvetii, a Gallic or Celtic nation, more numerous and warlike than the neighboring Gallic tribes. They were not known to the Romans until the time of Julius Caesar, who, s governor of Gaul, prevented their intended emigration, and after many bloody battles, in which even the Helvetian women fought, pressed them back within their frontiers. Helvetia, which was less extensive than the present Switzerland, was divided into four districts, which had an entirely democratical constitution. Cæsar subjected the country to the dominion of the Romans, who established several colonies there, the names of which only have remained (for example, Augusta Rauracorum in the Frickthal), and introduced Roman civilization. Christianity was afterwards introduced into Helvetia. (See Switzerland.)

HELVETIUS, Claude Adrien, born at Paris, 1715, received a careful education. The tales of Lafontaine delighted his childhood, as Homer and Curtius captivated his youth. The study of Locke's Essay on the Human Understanding, at the college of Louis-le-Grand, inspired him with a love of philosophy, to which he remained faithful. After the termina

tion of his law studies, he was placed by his father, a celebrated physician, Adrien Helvétius, at Caen, for the purpose of acquiring a practical knowledge of finance. At the age of 23 years, he obtained, through the patronage of the queen, the honorable and lucrative post of a farmergeneral. Alive to all the pleasures of society, which were now placed within his reach, he did not suffer himself to be alienated from the muses. He kept up his early intimacy with many distinguished men of letters, and, with a noble liberality, supported several young men of talents. As farmer-general, he was distinguished by his mildness and indulgence from his colleagues, whose base practices filled him with indignation. He therefore resigned his office, and purchased the place of maître d'hôtel to the queen. So ambitious was he of every sort of applause, that he even danced on one occasion at the opera. He aspired no less after literary fame. At first he directed his efforts to the mathematics, because he once saw a circle of the most beautiful ladies surrounding the ugly geometrician Maupertuis, in the garden of the Tuileries. He next attempted to rival Voltaire by a number of philosophical epistles, and he is also said to have written a tragedy. The brilliant success of Montesquieu's Esprit des Lois, then inspired him with the bold resolution of preparing a similar work. He therefore determined to retire into solitude. But he wished to sweeten his retreat by the society of a wife, and, in 1751, he married Mademoiselle de Ligniville, no less distinguished for her beauty than her wit. In the retirement of his estate of Voré, he devoted himself entirely to the happiness of his dependants, to domestic enjoyments, and to study. 1758, he published his book De l'Esprit, the materialism of which drew upon him many attacks. Objectionable as the doctrines in this work may be, it undeniably contains the most various information. Helvétius went, in 1764, to England, and, the year afterwards, to Germany, where Frederic the Great and other German princes received him with many proofs of esteem. After his return to France, he published his work De l'Homme, which is to be considered as a continuation of the former, and contains a fuller developement of the doctrines laid down in it; but, at the same time, many new ones, particularly such as relate to the science of education. Helvétius died in 1771 in Paris. Besides the above-mentioned works, he wrote epistles in verse, and an

In

allegorical poem, Le Bonheur. There are several complete editions of his writings. His wife, daughter of the count Ligniville, was one of the most excellent women of her time. After his death, she retired to Auteuil, where her house, like that of Madame Geoffrin, became the rendezvous of the most distinguished literati and artists of her time. She died Aug. 12, 1800, at Auteuil. (q. v.)

HELVIG, Amalia von; born at Weimar, Aug. 16, 1776, one of the most distinguished female poets of Germany. Her father travelled in France, England, Holland, and resided seven years in the Indies; and the mind of the lively girl was carly awakened by his narratives of what he had seen and heard in foreign countries. When eight years old, she spoke English and French fluently, besides her mother tongue. She had just reached the age of 12 years, when she lost her father; and the lady who now had charge of her education kept her so closely employed, that her poetic spirit found no opportunity to develope itself. She had already begun to make rhymes before she was seven years old. In her 15th year, she went to reside at Weimar, and soon after become acquainted with Bürger, Hölty, Stolberg, and other poets of the time. At this period she began to learn Greek, and, four weeks after entering on the study, was able to commence the reading of Homer. A little poem, written by her, was presented to Louisa, duchess of Weimar, and found its way to Schiller, who invited the fair author to his house at Jena. Göthe then passed much of his time at Jena, and the young poetess, in their society, heard the most instructive observations on poetry and literature. She was afterwards appointed lady of the court of Saxe-Weimar. Here she became acquainted with her future husband, whom she afterwards followed to Sweden. Her health suffered there, and she returned to her own country. In 1813, she published the first Taschenbuch der Sugen und Legenden. She has translated several works from the Swedish, among others, the Frithiofs-Sage of Es. Tegner, in 1826.

HELVIN; the name of a rare mineral, bestowed by Werner, in allusion to its suu-yellow color, found in a mine near Schwartzenburg, in Saxony, disseminated through an aggregate of chlorite, blende and fluor, in minute tetrahedral crystals, with their solid angles truncated. These crystals cleave parallel to the faces of the regular octahedron. Its hardness is about the same with quartz; its specific gravity,

3.100. It consists, according to Gmelin, of silex, 33.258; glucine and a little alumine, 12.029; protoxide of manganese, 31.817; protoxide of iron, 5.564; sulphuret of manganese, 14.000; and volatile matter, 1.555. HELVOETSLUYS; a seaport in the province of Holland and kingdom of the Netherlands, on the south side of the island of Voorn; 12 miles W. Dort; 15 S. W. Rotterdam; lon. 4° 8′ E.; lat. 51°. 50 N.; population, 1208. It has a good harbor, about 12 miles from the open sea, in the middle of a large bay, capable of holding the whole fleet of the country. The town is small, but well defended with strong fortifications. This is the general port for packets from England, chiefly from the port of Harwich. Here is a naval school. The ship channel, from Rotterdam to Helvoetsluys, was completed in November, 1830. William III sailed from this port for England, Nov. 11, 1688, with 14,000 men.

HEMERODROMI; a kind of couriers among the Greeks, famous for their extraordinary swiftness, and used, on that account, by the state, as messengers. They were employed, not only in times of peace, for the conveyance of letters, but also in war, as spies and bearers of orders. Of their great swiftness, the ancients report several instances.

HEMLOCK. It is still a matter in dispute, whether the hemlock, so celebrated among the ancients, and used at Athens for the execution of those condemned to death, was the plant at present denominated by botanists conium maculatum, or the cicuta virosa. These are both umbelliferous plants, resembling each other somewhat in appearance, but differing essentially in the degree of their virulence, the cicuta being by far the most powerful. Another opinion is, that the deadly potion was a compound of the juice of several umbelliferous plants. The conium maculatum is now naturalized in the U. States, and is an upland plant, common in waste places. The confusion of names in our materia medica, has rendered this plant liable to be confounded with the cicuta maculata, a truly native plant, growing in wet places, and possessing a much less nauseous odor than the preceding, but vastly more dangerous in its properties, and which is the cause of many deaths in the U. States, from its being eaten through mistake.

HEMLOCK SPRUCE. (See Spruce.)

HEMMLING, OF HEMMLINK, Hans; an eminent painter, who lived about the middle of the 15th century. He is

commonly thought to have been born in Flanders, and to have been carried, as a poor sick soldier, into St. John's hospital, at Bruges, where, on his recovery, his extraordinary genius for painting disclosed itself. According to later researches, he was probably born at Constance, and went to the Netherlands in order to study the art of painting in the school of Eyck. De Bast, of Ghent, asserts, in his Messager des Sciences et Arts (1825, No. 4-7), that the name of this artist was Hans Memling. Of his works, which have remained in the Netherlands, the above-mentioned hospital possesses the best; among them, a reliquary of St. Ursula, of which Van Keverberg published a description (1818), under the title Ursula, Princesse Britannique d'après la Légende et les Peintures d'Hemmling, containing also information on the other works of this artist.

HEMORRHAGE (Greek aipa, blood, and inyvvμ, to burst); a flux of blood from the vessels which contain it, whether proceeding from a rupture of the blood-vessels or any other cause. Hemorrhages produced by mechanical causes, belong to surgery; those produced by internal causes, to medicine. The cutaneous system is rarely, and the cellular and serous systems are never, the seats of hemorrhages; that of the mucous membranes is the most subject to them. The symptoms of the disease are not less various than its causes and its seats, and the treatment must of course be adapted to all these different circumstances. A hemorrhage from the lungs is called hemoptysis; from the urinary organs, hematuria; from the stomach, hematemesis; from the nose, epistaxis. HEMORRHOIDS (Greek alpa, and pew, to flow); literally, a flow or flux of blood. Until the time of Hippocrates, this word was used, conformably to its etymology, as synonymous with hemorrhage. It was afterwards used in a narrower sense, to indicate the flux of blood at the extremity of the rectum, and in some other cases which were considered analogous to it; thus we hear it applied to the flow of blood from the nostrils, the mouth, the bladder and the matrix. It is at present used to signify a particular affection of the rectum, although the disease is not always attended with a flux; in this sense it is also called piles. Certain general causes may produce a predisposition to his disease; in some cases, it appears to be the effect of a hereditary disposition; in general, it manifests itself between the period of puberty and old age, although infants and aged people are not entirely

exempt from its attacks. The bilious temperament seems to be more exposed to it than any other. Men are oftener affected with it than women, in whom it is sometimes produced by local causes. It often shows itself in subjects who pass suddenly from an active to a sedentary life, or from leanness to corpulency. Any circumstance which produces a tendency or stagnation of the blood at the extremity of the rectum, is to be reckoned among the local causes. The accumulation of fecal matter in the intestines, efforts to expel urine, the pressure produced by polypi, the obstruction of any of the viscera, especially of the liver, worms, the frequent use of hot bathing, of drastic purges, and particularly of aloes, long continuance in a sitting posture, riding on horseback, pregnancy, the accumulation of water by ascites, such are some of the ordinary causes of hemorrhoids. They are distinguished into several sorts, as external, when apparent at the anus; internal, when concealed within the orifice, blind or open, regular or irregular, active_or passive, periodical or anomalous, &c. There is also a great difference in the quantity of blood discharged; it is usually inconsiderable, but, in some cases, is so great as to threaten the life of the subject. The quality, color, &c., of the blood, also differ in different cases. The number, seat and form of the hemorrhoidal tumors likewise present a great variety of appearances. When the disease is purely local, we may attempt its cure; but in the greatest number of cases, it is connected with some other affection, or with the constitution of the subject. In these cases, if the tumors are not troublesome on account of their size, or if the quantity of blood discharged is not very consid erable, the cure may be attended with bad consequences. The best mode of treatment is, then, to recur to hygietic rather than medicinal influences. The subject should avoid violent exercises; but moderate exercise will be found beneficial; the food should not be too stimulating or nutritious. Travelling, or an active life, should succeed to sedentary habits. The constipation, with which the subjects of this disease are liable to be affected, should be remedied by laxatives or gentle purgatives. If bathing is used, it should be in lukewarm or cold water. Any thing which may be productive of a local heat, should be avoided; as warm seats, soft beds, too much sleep. If the pain is considerable, recourse should be had to sedatives, gentle bleeding, leeches. If the dis