and develop the legitimate resources of the country. Many checks on trade were removed, and taxation was more equally distributed. Merit alone was made the passport to promotion. Scientific exploration and enterprise were encouraged. No efforts were left untried to check infanticide and suttee. While setting an example of Christianity in his own person, and throwing the protection of the government around its observances, he discouraged secular officers from engaging in proselytism. He originated the policy which ended in the annexation of Oude, under his successor Lord Dalhousie. But in the midst of seeming prosperity the Sikhs were preparing an invasion of British territory from Lahore. The governorgeneral, having received timely information of their plans, collected a force of 32,000 men and 68 guns, and marched with it in person toward the threatened portion of the territory. On Dec. 13, 1845, learning that a large Sikh army had crossed the Sutlej, he issued a proclamation, and followed it up by immediately attacking the invaders. The battles of Moodkee, Ferozeshah, Sobraon, and Aliwal closed this short but hard-fought campaign of about 6 weeks, during which Hardinge, unwilling to snatch the honors of the field from his seniors in military rank, served as a volunteer under Sir Hugh Gough. The Sikhs were forced to bear the whole expense of the war and admit a British garrison into Lahore. For his services in this war he received the thanks of both houses of parliament, and a pension of £3,000 a year, and was raised to the peerage with the title of Viscount Hardinge of Lahore. The East India company gave him a pension of £5,000 a year, and he was also voted the freedom of the city of London. In Jan. 1848, he was superseded in his Indian government by Lord Dalhousie. In Feb. 1852, he was appointed master of ordnance by Lord Derby; and on the death of the duke of Wellington, in Sept. of the same year, he became commander-inchief of the forces. In Oct. 1855, he was advanced to the rank of field marshal. His administration at the horse guards was not popular. Having become paralytic, he resigned in July, 1856. He was possessed of a genial temperament and buoyancy of spirit which rendered him personally popular, and his bravery was attested by 16 medals for service in as many pitched battles. He left two sons, of whom the elder had been his secretary and the younger one of his aides-de-camp in India.

HARDNESS, the quality in solid bodies by which their particles resist a force, as that of a sharp-pointed instrument, applied upon the surface to impress or remove them. Its comparative degrees in different substances are tested by attempting to scratch one with the other, or touching each in succession with a file or knife blade. In mineralogy it is one of the important tests by which species are distinguished; and its degrees are expressed by numbers referring to the scale of Mohs, the German miner

alogist, which commences with the soft mineral talc, and ends with diamond, the hardest of all substances. It is as follows: 1. Talc, laminated light green. 6. Feldspar 2. Gypsum, crystallized. 8. Calcareous spar.

4. Fluor spar.

(orthoclase),

white, cleavable. 7. Quartz, transparent. 8. Topaz, transparent. 9. Sapphire, cleavable varie

ties.

10. Diamond.

5. Apatite, transparent variety. 5. 5. Scapolite, crystalline. Breithaupt introduces another degree between 2 and 3, and again between 5 and 6, making the scale consist of 13 degrees. Owing to the loose state of aggregation of the particles in some minerals, these are easily removed, and the specimens may consequently be erroneously referred to low degrees of hardness, when a more careful examination would show that they are capable of scratching the smooth surface of other bodies of known high degrees of hardness. Brittleness or a tendency to fracture is a quality to be distinguished from hardness. Pure crystals are to be selected when practicable for establishing the hardness of mineral species, and it should be observed whether dissimilar faces of the crystal give different or the same results.

HARDOUIN, JEAN, better known as PÈRE HARDOUIN, a French Jesuit, celebrated for his learning and his paradoxical opinions, born in Quimper, Brittany, in 1646, died in Paris, Sept. 3, 1729. He entered the order of Jesuits at the age of 20, and after teaching rhetoric for some time, went to Paris to finish his classical studies. Being intrusted with the preparation of Pliny's "Natural History" for the Delphin series of classics, then in progress, he discovered that a knowledge of numismatics was requisite for a clear elucidation of the text, and by assiduous study made himself a thorough master of the science. His edition of Pliny was published in 1685 (5 vols. 4to.), and met with the highest commendations of the learned throughout Europe. Huet observed of it that Père Hardouin had completed in 5 years a work which would have occupied 5 other savants 50 years. Elated with his sudden fame, Hardouin embroiled himself in bitter controversies by speaking with con tempt of all other antiquaries, and endeavoring to support his positions by the most startling theories. In his "Chronology Explained by Medals" (2d part, 1697) he maintained that of all the ancient classics none are genuine but Homer, Herodotus, Cicero, Pliny the Elder, the Georgics of Virgil, and the satires and epistles of Horace; and that with the aid of these the monks of the 13th century had fabricated all the others, and reconstructed ancient history. The Eneid he regarded as an allegory of the progress of Christianity, and explained its several parts accordingly. The work was suppressed by order of parliament, but surreptitiously reprinted with out change. In 1708 he was compelled by his superiors to recant his opinions, but he still clung to them, and reproduced them in subsequent works. In 1715 he published in 12 vols. fol. his great Conciliorum Collectio, with the preparation of which he had been charged by

the general assembly of the clergy of France. It embraces the councils held from the year 34 to 1714, including more than 20 whose acts had not before been published; but Père Hardouin is accused of having suppressed some important pieces and replaced them by apocryphal passages. At the request of 6 doctors of the Sorbonne the parliament arrested the sale of the work, and caused a number of leaves to be cancelled. Notwithstanding his labor on this collection, Hardouin regarded all the councils prior to that of Trent as chimerical. His other works include Chronologie de l'Ancien Testament (1677); Nummi Antiqui Populorum et Urbium (1684); De Nummis Antiquis Coloniarum et Municipiorum (1689); De Nummis Samaritanis, and De Nummis Herodiadum (1691); Chronologia ex Nummis Antiquis instituta (1693); Commentaire sur le Nouveau Testament; De la situation du paradis terrestre; Opera Selecta (1709), &c.

HARDWICK, CHARLES, an English theologian, born in 1821, died Aug. 18, 1859, from an accident in ascending the Pyrénées near Bagnères de Luchon. He was a fellow of St. Catharine's hall, Cambridge, where he resided and held the office of Christian advocate in the university. In 1853 he was appointed professor of theology in Queen's college, Birmingham; in 1855, divinity lecturer at Cambridge; and a few months before his death, archdeacon of Ely. He published "History of the Articles on Religion" (London, 1851; 2d ed. 1859); "Twenty Sermons for Town Congregations" (1853); "History of the Christian Church in the Middle Ages;" "History of the Christian Church from Gregory the Great to the Reformation" (1856), &c. He commenced a work entitled "Christ and other Masters," comparing Christianity with other forms of religion, of which 4 parts had appeared (1855-'8), the 1st introductory; the 2d, the religions of India; the 3d, of China, America, and Oceanica; and the 4th, Egypt and Medo-Persia. He also prepared an edition of the Anglo-Saxon and Northumberland version of the Gospel of St. Matthew, and was connected with other literary enterprises.

HARDWICKE, PHILIP YORKE, first earl of, an English lawyer, born in Dover, Dec. 1, 1690, died March 6, 1764. During his studies at the Middle Temple he became acquainted with Lord Chief Justice Macclesfield, who employed him as companion and tutor to his sons, and used his influence to push him forward at the bar. The partiality which Lord Macclesfield showed him in court was even the subject of complaint in the profession. He was called to the bar in 1715, and when his patron was made lord chancellor in 1719 he entered parliament as member for Lewes, the expenses of his election being defrayed by the government. The next year he was appointed solicitor-general; soon afterward he was knighted; in 1724 he became attorney-general, in 1733 lord chief justice of the king's bench and Baron Hardwicke of Hardwicke, and in 1737 lord chancellor. During the whole period of his public life he enjoyed

the highest reputation for integrity and wisdom. But 3 of his chancery judgments were appealed from, and those were confirmed. During the king's absence in 1740, '48, and '52, he was one of the justices chosen to administer the government; and in 1746 he was named lord high steward of England to preside at the trial of the rebel Scottish lords, Kilmarnock, Cromartie, Balmerino, and Lovat. In 1754 he was created Viscount Royston and earl of Hardwicke. When the duke of Newcastle went out of office in Nov. 1756, he resigned the great seal and passed the rest of his life in retirement.

HARDY, a N. co. of Va., bordering on Md., drained by Cacapon and Lost rivers and the N. and S. branches of the Potomac; area, 1,400 sq. m.; pop. in 1850, 9,543, of whom 1,260 were slaves. It has a mountainous, rocky surface, being crossed by ridges of the Alleghanies, and lying partly on the W. slope of North mountain. It has valuable mines of iron ore, and contains many fertile valleys. The productions in 1850 were 327,846 bushels of Indian corn, 85,225 of wheat, 6,362 tons of hay, 119,686 lbs. of butter, 1,197 of tobacco, and 32,176 of wool. There were 21 grist mills, 13 saw mills, 4 wool carding mills, 5 tanneries, 1 newspaper office, 18 churches, and 622 pupils attending public schools. Value of real estate in 1856, $3,889,191, showing an increase since 1850 of 46 per cent. Capital, Moorefield.

HARE, the name of the small rodents of the family leporida, and the genus lepus (Linn.), which includes also the rabbits. This has fewer species than most other families of rodents, and presents the exceptional characters of large openings of the skull, an imperfect condition of the palate, the nasal process of the superior maxillary perforated, large orbits meeting in the middle line of the cranium, small temporal fossæ, and an increased number of incisor and molar teeth; the scapular spine has a long acromion process, sending down a considerable branch at right angles; there are 5 toes on the fore feet and 4 on the hind; the ears are very large, as long as or longer than the head; the tail short and bushy, either rudimentary or carried erect; hind legs much longer than the anterior, and formed for leaping; the stomach is simple, or partially divided internally, and the cæcum very long and divided into numerous cells by tendinous bands; a part of the inner surface of the cheeks is clothed with small hairs. Hares are found in all parts of the world except Australia, but most abundantly in North America, and chiefly confined to the northern hemispheres, extending even into the polar regions. For full particulars on the various species see "Waterhouse's Natural History of the Mammalia," vol. ii., pp. 9-147; for the American hares see vol. viii. of the "Pacific Railroad Reports," in which Mr. Baird proposes several divisions founded on the size, proportions, and curvature of the skull, and the size and divergence of the post-orbital processes. There are only 2 genera of the family, lepus and lagomys;

the latter will be described under PIKA. The genus lepus has the following dental formula: incisors, and molars, a larger number than in other rodents; 2 small incisors are placed behind the principal pair, which are grooved in front, all being white, and not as deeply as usual implanted in the alveoli; the molars are rootless. There seems no osteological difference between hares and rabbits; the latter, however, are gregarious and make burrows in which the young are raised, while the former are more or less solitary, and merely make "forms" of grass on which they sit; rabbits are born blind and naked, but hares are said to have the eyes open and the body covered with hair at birth. The distinction being based chiefly on habits, there are hardly any species in America like the rabbit of Europe (L. cuniculus, Linn.), unless they be the gray rabbit (L. sylvaticus, Bach.) and the jackass rabbit (L. callotis, Wagler); and it is not certain that any other old world lepus has the habits and peculiarities of L. cuniculus. The last 3 species will be noticed under RABBIT. The common hare of Europe (L. timidus, Linn.) has ears longer than the head, fringed anteriorly with long hair; the fur mottled with black and ochrey brown, with rufous tints on the neck and outer side of limbs; the abdomen, inner side of limbs, and tail white; upper surface of tail and ears black; length from tip of nose to root of tail, along the curve of the back, 23 inches; weight, 8 to 12 lbs. Black and white varieties sometimes occur, but the color is not changed in winter as in the varying northern hares. This species is found generally throughout Europe, except in the coldest parts. The timidity of the hare is proverbial, and its speed made it a favorite object of the chase from the times of the Romans; the principal use of the greyhound is to pursue this animal. The eyes are lateral and prominent, and vision extends to objects on all sides at once; a very acute sense of hearing and smell and great speed are given for further protection against its numerous enemies; the palms of the feet are covered with hair; the nostrils are circular, almost hidden by a fold which may be closed; the upper lip is cleft; the opening of the ears can also be closed; the mammæ are 10. They are able to reproduce at a year old; the period of gestation is 30 days, and from 2 to 5 are produced at a birth. They remain quiet during the day in their form or seat, which is a mere depression in the ground near some bush, coming out toward evening in search of food; the color so much resembles that of the objects among which they rest, that, as if conscious of the resemblance, they will generally remain quiet in their form until they are almost trodden upon. This species readily takes to the water, and swims well; it sits upon its tarsi, and uses its fore paws in holding food and cleansing its fur, though, from its incomplete clavicles, less perfectly than in the claviculated rodents; it drinks lapping, and can bite severely. Early in spring the sexual appetite is very strong, and the animal acts so

strangely that "to be as mad as a March hare" has become a proverb. Its intelligence is limited, but its instincts in avoiding its enemies are remarkable. The hare and rabbit were ranked among ruminating animals by the Mosaic law, but were forbidden to the Jews because the hoofs were not divided; Moses probably called the hare a ruminant from the partial division of the stomach, and the evident lateral movement of the lower jaw; Waterhouse confirms the statement of the Jewish lawgiver, and says the motion of the jaws must be chiefly lateral, as the crowns of the molars are never worn flat as in other rodents with rootless molars. The food of the hare is entirely vegetable, and its flesh is delicate, nutritious, and universally esteemed.-The varying haré (L. variabilis, Pall.) is smaller than the common species, with smaller and less black ears, shorter tail, and without the mottled appearance and white mark on the cheek of the latter; in summer the general color is rusty brown, finely pencilled with black and rufous yellow above, and impure white below; tail white, grayish above. In winter the fur is white, with ears black-tipped, the change of color being due to the cold of the season in the northern regions which it inhabits. It is found in northern Europe and Asia as far as the arctic ocean, but is wanting in central Europe except in Alpine regions. Twenty other species of hare are described by Waterhouse in Europe, Asia, and Africa.-Among the American species which grow white in the winter is the polar hare (L. glacialis, Leach), the largest of the family, exceeding a large cat; it measures about 2 feet to the root of the tail, the latter being about 3 inches, and the ears about 4. The color in winter is pure white, with the ears black-tipped before and behind, and the soles dirty yellowish white; in summer it is light brownish gray above varied with black, rump and upper surface of tail dark plumbeous, ears glossy black with whitish posterior margin, and below whitish with a sooty tinge; the head is arched and wide, the ears broad, the tail short and hardly perceptible amid the dense hair; the fur is soft, fine, and full. This much resembles the European L. variabilis, and is distinguished chiefly by greater blackness of the ears; it is found in arctic America, and as far south as Newfoundland, in the most desolate and sterile regions, defying the inclemency of the polar winter; it feeds on berries, bark, twigs, and evergreen leaves; it is not very shy, though difficult to take in its favorite snowy localities; its range probably extends from Greenland to Behring's strait. Indians, trappers, and arctic travellers have often been saved from starvation by this beautiful animal. Its eyes are adapted for the twilight and auroral light of the polar countries, which, with the brightness of the pure snow, are always sufficient for its needs; its flesh is said to be delicious; from the shortness of the arctic summer this species produces young but once a

year, from 3 to 6 at a birth; the fur is softer than the finest wool; its summer pelage does not last more than 3 or 4 months. The weight, in good condition, is from 10 to 14 lbs.-The northern hare, sometimes called white rabbit (L. Americanus, Erxl.), is a little smaller than the last; the color in winter is whitish, but the hairs at the root are gray and pale yellow in the middle; in summer the general hue is reddish brown, pencilled with black above, and the under parts white, very much like that of the L. timidus. It is found in the eastern portions of the continent from Pennsylvania and Virginia as far as lat. 68° N.; its favorite haunts are thick woods, where it is hunted with difficulty by dogs; its food consists of grasses, bark, leaves, young twigs, buds, and berries, and, in a domesticated state, of vegetables and fruits. This is the swiftest of the American species, and has been known to clear 21 feet at a single leap; like other hares and rabbits, it is in the habit of beating the ground with the tarsi, when alarmed or enraged; it is fond of pursuing a beaten path in the woods, and is often snared in such places. Its flesh is not much esteemed. Its enemies, beside man and dogs, are the lynx and other carnivorous mammals, hawks, owls, and even the domestic cat. It is more fierce than the rabbit, and will bite and scratch severely. The skin is very tender, and the fur little valued by furriers; the hind feet are used by the hatter in finishing his fabrics. The red hare (L. Washingtonii, Baird) is found on the N. W. coast; the prairie hare (L. campestris, Bach.), a large species, changing to white in winter, in the great plains of the Missouri and as far as the Columbia river; and the California hare (L. Californicus, Gray) on the Pacific coast.-The swamp hare (L. aquaticus, Bach.) is as large as the northern species, with long ears and tail; dark grayish brown above and white below; it is strong and swift; the fur is coarse and glossy; the feet are not densely clothed with hair, but the toes are slender, with small pads, pointed, and with visible claws. This species prefers low marshy places, in the vicinity of water, to which it is fond of resorting; it is an excellent swimmer, subsisting chiefly on the roots of the iris and other aquatic plants; when started, it suddenly leaps from its form, and makes for the nearest water, seemingly conscious that in that element all traces of its scent will be soon lost; it is fond of hiding beneath the roots of trees overhanging the water, in hollows under river banks, and in decayed trees. It is most abundant in the swampy tracts bordering on the Mississippi and its tributaries in the S. W. states; it has not been seen E. or N. of Alabama, according to Bachman.-The marsh hare (L. palustris, Bach.) is smaller than the rabbit, with short ears and tail; the legs are short and the feet are thinly clothed with hair; the general color above is yellowish brown, beneath gray; the eyes are remarkably small. It is found in the maritime districts of the southern states, espe

cially in the neighborhood of rice fields; in these miry and unwholesome swamps, "surrounded by frogs, water snakes, and alligators, this species resides throughout the year, rarely molested by man." It is an excellent swimmer, and is perfectly at home in the miry pool and boggy swamp; it runs low on the ground, and is rather slow and clumsy in its motions. Its flesh is considered superior to that of the gray rabbit. Like other species of the genus, it is infested in the summer and autumn with the larvæ of an astrus, which penetrate the flesh and keep the animal lean from constant irritation. Its food consists principally of roots, bulbs, and twigs of plants growing in marshes. It breeds several times a year, having from 5 to 7 at a birth; the young are placed in a kind of nest, made of rushes and lined with hair. Several other species of hare are described by Waterhouse and Baird.

HARE, JULIUS CHARLES, an English divine, archdeacon of Lewes, born at Hurstmonceaux, Sussex, Sept. 13, 1795, died there, Jan. 23, 1855. He was the son of the Rev. Robert Hare, rector of Hurstmonceaux, and the grandson of the learned bishop Francis Hare. After passing much of his time on the continent, he studied at the Charterhouse, whence he was removed in 1812 to Trinity college, Cambridge, where he remained, with a brief interval, for 20 years, being graduated bachelor in 1816, and master in 1819; he became a fellow in 1818, and assistant tutor in 1822. During this period he applied himself especially to classical and philological learning, German literature, and the writings of Coleridge and Wordsworth. In 1827 appeared the first series of "Guesses at Truth, by Two Brothers," a volume of miscellaneous apophthegms and reflections, the joint production of himself and his elder brother, Augustus William. A second edition appeared in 1838 with additions by himself, and from the posthumous papers of his brother; and a second series was subsequently published (2d ed. 1848). At Cambridge he likewise united with Thirlwall in translating the first two volumes of the 2d edition of Niebuhr's "History of Rome" (1828-'82), and he published in 1829 a vindication of the work from the charges of the "Quarterly Review." He also contributed largely to the "Philological Museum." His rugged style and odd spelling of some words led Sir William Gell to allude to him punningly as Julius Hirsutus. In 1832 he was instituted to the rectory of Hurstmonceaux, the advowson of which was in his family; was appointed archdeacon of Lewes in 1840; was collated to a prebend of Chichester in 1851; and was nominated a chaplain to the queen in 1853. Soon after settling at Hurstmonceaux he married the sister of his friend the Rev. F. D. Maurice, and began his intimacy with Chevalier Bunsen, who dedicated to him, "as a monument of a life-long friendship," the first volume of his "Hippolytus and his Age." Though he devoted himself faithfully and

zealously to the duties of his office, he achieved his least successes as a preacher and parish minister. Even the sermons which he delivered before the university of Cambridge, where he had an audience most suited to his style of thought and expression, were somewhat impatiently listened to, and the effect of his official charges was marred by their prolixity. His mental cast and habits fitted him less for the pulpit than for his study, surrounded by a library which ultimately covered nearly all the walls of his rectory. It was chiefly in the ecclesiastical controversies of his time that he exhibited the character of an original and profound thinker, and his personal influence was such that he was sometimes called the leader of the Broad church party of the Anglican church. Many of his charges were controversial discussions. His collected works would form a commentary on the leading events of the last quarter of a century having special reference to the church of England. Beside several volumes of sermons, his principal later publications were the "Means of Unity, a Charge, with Notes" (1847); the "Duty of the Church in Times of Trial, a Charge, with Notes" (1848); the "True Remedy for the Evils of the Age, a Charge, with Notes" (1850); a "Letter to the Hon. R. Cavendish, on the recent Judgment of the Court of Appeal as affecting the Doctrine of the Church" (1850); the "Contest with Rome, a Charge, with Notes" (1852); a "Vindication of Luther against some of his recent English Assailants" (1854), among whom were Hallam in his "Literary History of Europe," J. H. Newman, W. G. Ward, and Sir William Hamilton; and an edition of the "Essays and Tales of John Stirling, with a Memoir (2 vols., 1848), which gave so little satisfaction to Mr. Carlyle that he wrote a rival "Life of Stirling."-AUGUSTUS WILLIAM, brother of the preceding, and associate author of the first series of "Guesses at Truth," born in 1794, died in Rome, Feb. 18, 1834. He was a fellow of New college, Oxford, and became rector of Alton-Barnes in 1829. Before his decease, says his brother, he had nearly ceased "guessing at truth," in order to devote himself to the duties of his profession, and his "Sermons to a Country Congregation" (2 vols., London, 1837; 7th ed. 1851) were pronounced by the "Edinburgh Review" to be, "for an illiterate audience, an audience of rustics, perfect models of what discourses ought to be."

HARE, ROBERT, an American chemist and physicist, born in Philadelphia, Jan. 17, 1781, died there, May 15, 1858. His father, an English emigrant, settled in Philadelphia, and married an American lady. He established there an extensive brewery, and his son in early life managed the business. His tastes, however, led him away to scientific pursuits. He attended the courses of lectures on chemistry and physical sciences, and before he was 20 years of age he joined the chemical society of Philadelphia. At this early age he communicated

to the society a description of his first and most important scientific invention, the oxyhydrogen blowpipe, which he then called the hydrostatic; blowpipe, and which was afterward named by Prof. Silliman the compound blowpipe. His memoir, published in 1801, appeared the next year in Tilloch's "Philosophical Magazine" (London), and also in the Annales de chimie (1st series, vol. xlv.). At this period the subject of combustion was very imperfectly understood, and even Lavoisier, who had discovered that heat sufficiently intense to fuse alumina might be obtained by directing a jet of oxygen upon charcoal, and who had burned the elements of water together to produce this fluid, failed to discover that by this union of hydrogen and oxygen in combustion the most intense degree of heat known might be obtained. By means of this apparatus Dr. Hare was the first to render lime, magnesia, iridium, and platinum fusible in any considerable quantity; and he is perhaps the only one who has obtained calcium in a pure metallic state, and strontium without alloy of mercury. In addition to these discov eries, Dr. Hare first announced that steam is not condensable when combined in equal parts with the vapor of carbon. For the invention of the blowpipe Dr. Hare received the Rumford medal from the American academy at Boston. In the article BLOWPIPE the subject is more particularly treated, and the attempts are noticed that were made in England to deprive Dr. Hare of the credit of the discovery. In 1818 Dr. Hare was appointed professor of chemistry in the medical school of the university of Pennsylva nia, and continued in this office till his resignation in 1847. His course of instruction was marked by the originality of his experimenta and of the apparatus he employed. His instruments, often designed and sometimes made by himself, were furnished in the greatest profu sion, and always of large dimensions and of the most perfect plans; no expense nor personal labor was spared to render every piece of apparatus as complete as possible. The great collection which he accumulated he bestowed, after resigning his office in the university, upon the Smithsonian institution, of which he was one of the few life members. One of the most useful small instruments of his invention is that called the valve cock or gallows screw, by means of which per fectly air-tight communication is made between cavities in separate pieces of apparatus. To his zeal and skill in devising and constructing im proved forms of the voltaic pile, as remarked by Prof. Silliman ("Journal of Science," 2d series, vol. xxvi. p. 103), American chemists are indebted for the distinguished success they attained in applying the intense powers of extended series of voltaic couples long in advance of the gen eral use of similar combinations in Europe. In 1816 he invented the calorimotor, a form of battery described in ELECTRO-DYNAMICS, by which a large amount of heat is produced with little intensity. With the modified form of it called the deflagrator, devised in 1820, Prof.