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form any distinct idea of anything capable of being excited, and communicated in these experiments except it be Motion."

Sir Humphrey Davy, the associato of Rumford, in the Royal Institution, adopted these views concerning heat. Ho instituted some delicate experiments by which they were strikingly confirmed. One of these consisted in rubbing two pieces of ice together in a vacuum, at a temperature below the freezing point. The heat of friction melted the ice. The old explanation of the fact was that the friction liberated the latent caloric of the ice. To this, Davy replied: "If I by friction liquefy ice, I produce a substance which contains a greater absolute amount of heat than the ice; and in this case it cannot with any show of reason be affirmed, that I merely render sensible the heat hidden in the ice, for that quantity is only a small fraction of the heat contained in the water." Davy also propounded the hypothesis of atomic vibrations or oscillations, as the cause of thermal phenomena. This cannot be better stated than in his own words: "It seems, possible to account for all the phenomena of heat, if it be supposed that in solids the particles are in a constant state of vibratory motion, the particles of the hottest bodies moving with the greatest velocity, and through the greatest space; that in fluids and elastic fluids, besides the vibratory motion, which must be conceived greatest in the last, the particles have a motion round their own axes with different velocity, the particles of elastic fluids moving with the greatest quickness, and that in ethereal substances the particles move round their own axes, and separate from each other, penetrating in right lines through space. Temperature may be conceived to depend upon the velocity of vibrations; increase of capacity in the motion being performed in greater space; and the diminution of temperature during the conversion of solids into fluids or gases, may bo explained on the idea of the loss of vibratory motion, in consequence of the revolution of particles round their axes, at the moment when the body becomes fluid or aeriform, or from the loss of rapidity of vibration in consequence of the motion of the particles through space."

Tho researches of Davy upon this subject may be regarded as continuing those of Count Rumford. In 1812 he wrote: "The immediate cause of the phenomena of heat, then, is motion, and the laws of its communication are precisely the same as the laws of the communication of motion." Seguin in 1S19 published a work entitled De I Influence des Chemins de Per, in which ho shows that the old theory leads to the absurd conclusion, that a limited quantity of heat can produce an unlimited quantity of chemical action. He says: "It appears to mo more natural to suppose that a certain quantity of caloric disappears in the very act of tho production of the force or mechanical power, and reciprocally the mechanical Vol. in—32 A

force which disappears during the lowering of tho temperature of a gas is tho measuro and the representation of the elimination of heat."

The time had now arrived for the reception of these views by many minds, and accordingly we find that, during the next ten years, eminent scientific men in England, France, Germany, Denmark, and Amafica, devoted themselves with assiduity to their theoretical and experimental development. In 1850 Joulo's law was established, which placed the subject upon an immovable experimental basis. While, during the same year, Dr. Carpenter formally extended the research so as to include the vital forces. His paper on the correlation of the physical and vital forces, was published in the philosophical transactions for that year. From that time, the views have been gradually accepted by scientific men, until they may now bo regarded as generally established. Science has thus changed her standpoint, and all phenomena are presented in a new light. The most important results alike to science, philosophy, and education, may be expected to follow this revolution of scientific thought.

HILDRETH, Samuel Peescott, M. D., an American historian and physicist, born in Methuen, Massachusetts, Sept. 30th, 1783, died at Marietta, Ohio, July 24th, 1863. His boyhood was passed on his father's farm, until ho was fifteen years old, his primary education being received at a common school. From thence he was sent to Phillips Academy, Andover, and the Franklin Academy, in the North Parish. He studied medicine with Dr. Thomas Kittridge, a noted surgeon of Andover, and received a diploma from the Medical Society of Massachusetts in Feb., 1805. He commenced the practice of his profession in New Hampshire, but, in 1806, having made up his mind to settle in Ohio, journeyed thither on, horseback, and after spending about two months in Marietta, located himself at Belpre, where, in 1807, he married Miss Cook (formerly of New Bedford, Mass.). He was very successful in practice; but, in 1808, removed to Marietta, where the duties of his profession wero less arduous, and where he remained to the close of his life. In 1810 and 1811 he served in the Ohio Legislature as a supporter of the administrations of Jefferson and Madison; but on the formation of tho republican party, in 1854, he connected himself with it. For a period of nearly forty years he was a contributor to li Silliman's Journal of Science," his articles embracing a wide range of scientific subjects, but more especially devoted to meteorology, geology, and palaeontology. In 1837 he was a member of the Geological Survey, and delivered the annual address at Cleveland, before tho Medical Society, of which he was then president, giving a history of the diseases and climato of Southeastern Ohio, from its settlement, which was published by the Society. The same year he published a history of the settlement of Belleville, "Western Vir

ginia, in the "Hesperian," a magazine published in Cincinnati. In 1848 he prepared his "Pioneer History," an account of the first examinations of the Ohio valley, and early settlement of the Northwest Territory, which, with his " Lives of the Early Settlers of Ohio," were published under the auspices of the Ohio Historical Society; bjth works of great value. In 1830 he commenced the collection of a cabinet of natural history, and in the course of eight years had gathered more than 4,000 specimens, arranged, classified, and catalogued, and all this without interfering with the duties of his profession. Ho collected also more than 5,000 shells, some of which he exchanged for books of a scientific nature, thus enabling him in time to form a large and valuable scientific library, which, previous to his death, he donated, together with his cabinet, to Marietta College. He was in the enjoyment of good health and remarkably active in all his movements until a fortnight preceding his death.

HOLSTON RIVER. This is the largest branch of the Tennessee river. Ittis formed by the junction of the north and south forks which rise among the Alleghany Mountains of Virginia, and unite at Kiugsport, Sullivan county, Tennessee. Flowing thence and passing Knoxville, in East Tennessee, it unites with the Clinch river, at Kingston. The length of the main stream is estimated at two hundred miles.' It is navigable by small steamboats to Knoxville, and during the winter they can ascend to Kingsport.

HOPE, George William, M. P., born at Blackheath in 1808, died at Stiffness, Haddingtonshire, October 18th, 18G3. lie was a son of the Hon. Alexander Hope, was educated at Christ Church, Oxford, and called to the bar at Lincoln's Inn, in 1831. _. The death of an elder brother, however, altered his position, and removed him from the ranks of practising barristers. Soon after, his attention was turned to politics, and in 1837 ho was elected for Weymouth. In 1842 ho was returned for Southampton, and becamo Under Secretary for the Colonies, an appointment which he held until the retirement of Lord Stanley, the Colonial Secretary, in December, 1845. In 185!) he again came forward, and was chosen for New Windsor as a supporter of the Derby Administration. He retained his seat until his death.

HOPE, Admiral Sir Hexet, K. C. B., born in 1787, died at Holly Hiil, Hampshire, September 23d, 1803. He entered the navy in the spring of 1798, as midshipman, became lieutenant in 1804, and captain in 1808. He served in the Mediterranean on board the "Kent," and was afterward transferred to the "Swiftsure," and was on that ship when she was taken a prize by a portion of the French squadron which had escaped from Toulon. In 1815, he was in command of tho "Endymion," forty gun frigate, and distinguished himself in the engagement with the American ship "Presi

dent," which he took as a prize to Spithead, and was presented by the admiralty with a gold medal, and the nomination of a Companion of the Order of the Bath. ' He was successively advanced to the rank of rear-admiral, vice-admiral, and admiral, and was also aidede-camp to AVilliam IV., and to her Majesty. In July, 1855, he was nominated a Knight Commander of the Order of the Bath. He left personal property to the amount of £70,000, nearly one half of which he bequeathed to various religious and charitable societies.

HUBBARD, Joseph Stillman, an American astronomer, born at New Haven, Conn., in 1623, died in that city August 16th, 1863. He graduated with high honor at Yale College, in 1843, giving evidence of extraordinary mathematical ability, and in the spring of 1844 was appointed an assistant to the late distinguished astronomer, Sears C. Walker, in the High School Observatory, Philadelphia. In the autumn of tho same year he was employed by Captain (now Major-General) Fremont to reduce his Rocky "Mountain Observations," and was invited to accompany him on his next expedition. Declining this offer, he was, at the instance of Col. Fremont and Senator Benton, appointed by Hon. George Bancroft, then Secretary of the Navy, a professor of mathematics in the U. S. Navy, and assigned to duty in tlie Naval Observatory, then just established at Washington. This post he filled with remarkable zeal and fidelity to the time of his death. The printed volumes of the Washington Observations are full of the evidences of his skill as an observer and a computer. Professor nubbard was a frequent and valued contributor to the "Astronomical Journal." His investigations on Biela's comet, and on the great comet of 1843, aro recorded in that journal in a serks of elaborate papers. Ho also contributed papers on the orbit of Egeria, and many other topics. Tho article "Telescope," in the New American Cyclopaedia, a paper of great labor and research, was also from his pen. His labors of love in the cause of benevolence and religion were not less zealous than in the paths of science.

HUNT, Major Edwaud B., an officer of U. S. volunteers, born in Livingston county, N. Y.. in 1822, died at tho Brooklyn Marine Hospital, Oct., 2d, 1863. He was appointed to the Military Academy from his native State in 1841, graduated second in the class of 1845, was appointed second lieutenant in the corps of engineers, and was assigned to duty as assistant to the Board of Engineers for Atlantic Coast Defence. After serving in this capacity a year, he was called to fill the important position of principal assistant professor of civil and military engineering at the Military Academy, West Point, where he remained until 1849. when he was employed as assistant-engineer upon Fort Warren, Boston harbor, Mass. From 1851 to 1855 he was the assistant of Prof. Bacho, in the Coast Survey Bureau. From 1S55 to 1857 he was engaged in the engineering operations in Newport harbor, R. I., and constructed and repaired many important lighthouse structures on the coast. In 1857 he was ordered to Key West, where, for five years, he assisted in the construction of fortifications and other defensive works on that island, receiving his captaincy while serving there, July 1st, 1S59. It was chiefly through his instrumentality that the forts of Southern Florida were withheld from the Confederates after the war actually commenced. In 1862 he was appointed chief-engineer of the 5th army corps, commanded by Major-General Banks, and from this duty was relieved and placed on special service under tne Navy Department, in order to superintend the construction of his submarine battery, an invention of his own, which he was sanguine would successfully defeat any naval attacks which might be made by the most powerful fleets upon our harbors. While engaged in making some experiments with this battery, a shell prematurely discharged, immediately after which ho descended into the caisson, and, in attempting to ascend, being probably overcomo by the gas, fell backward, striking his head and causing concussion of the brain, from which he died the following day. Major Hunt was a brother of ex-Governor Washington Hunt of New York, and was a man of great ability and scientific attainments, and a frequent and valued contributor to the transactions of the American Association for the Advancement of Science, and to various literary and scientific works of the country. He was a man of sincere patriotism, and thoroughly conscientious in the discharge of his duties as an officer and as a man.

IIYGIEN'E IN THE ARMY. The regular army of the United States, before the commencement of tho present war, seldom numbering in its ranks more than 12,000 or 13,000 men, and with a medical and hospital service corresponding to its limited numbers, hadlittlo need of special rules of hygiene, or the elaboration of any extensive system of regulating the health and physical comfort of its forces. But when a volunteer army of more than half a million of men was suddenly called into existence, men, too, to whom camp life was an entirely new experience, who had for the most part little or no knowledge of the art of cookery, or of the thousand causes of disease which lurked in their new mode of life, in the climate, exposure, over exertion, unsuitable or insufficient food, clothing, &c, it became evident that it required fully as much medical skill and care to prevent disease as to effect a cure when it had made its appearance. The medical department of the Government, aided m this matter most effectually by the Sanitary Commission, found it necessary to give special instruction to the army surgeons, whether engaged in examining recruits or in service on t'i« field or in the hospitals, in matters relates to the hygienic condition of the force; and

during the past year, in addition to monographs on particular branches of the subject by subordinate medical ofiicers of the army, the accomplished surgeon-general has, by the most indefatigable industry, found or made leisure to prepare an admirable treatise on "Hygiene in the Military Service."

The first step in the way of prevention of disease in the army must be taken in the examination of recruits. The ignorance or incompetence of tho examining surgeons in the first two years of the war, and sometimes it is to be found baser motives, led to great abuses in this respect. "Thousands of incapacitated men," says Surgeon-General Hammond, " were, in the early stages of the war, allowed to enter the army, to be discharged after a few weeks' service, most of which had been passed in the hospital. Many did not march live miles hefore breaking down, and not a few never shouldered a musket during the whole time of their service. * * * * Cases of chronic ulcers, varicose veins, epilepsy, and other conditions unfitting men for a military life, came frequently under my notice. Tho recruits were either not inspected at all by a medical officer, or else the examination was so loosely conducted as to amount to a farce. I know of several regiments in which the medical inspection was performed by tho surgeon walking down the line and looking at the men as they stood in the ranks." There has been great improvement in these examinations since the autumn of 1862, hut even now too many men unfit for tho service are smuggled into it, through the lack of vigilance on tho part of the inspector. Tho enlistment of weak, malformed, or sickly soldiers is a great crime against the service. The soldier, to bo capable of serving his country effectively in the field, requires not only sound health but the ability to endure fatigue, hardships, exposure, and vicissitudes of climate with impunity. To admit into tho ranks a soldier who docs not possess this ability, inflicts upon the army not only the probable loss of his services, very often at a time when they are most needed, but, if he is consigned to a hospital, requires the care of others for his nursing, who might otherwise be employed in the national defence. The minimum age at which volunteers are received (eighteen years, and in many cases by the connivance of examining officers, below that age) is too young for serviceable soldiers. These young recruits break down under the severe marches and privations of the camp, and are more liable to those terrible scourges of the army, diarrhoea and dysentery, as well as to a fatal termination of wounds than those who enter tho army at twenty or over. The height of the recruit (our minimum limit is five feet three inches, and there is no maximum, as there should be), the capacity of the chest, vigor of tho system, and general aptitude for the soldier's profession, are all points of great importance, and must be carefully examined by the surgeon before deciding to accept a volunteer. The diseases, defects, or deformities which afford cause for rejection of recruits have been fully laid down in the books of instruction for tho examining surgeons, and do not come properly within the range of our inquiries. It is, however, to carelessness and neglect in the inspection of those who havo offered to enter tho service that a large portion of the sickness of the new troops is due, and from this cause more than any other has it happened, more than once, that with very large numbers on the rolls, tho effective force of our armies has often been very small.

But tho soldier once received into the army, there are many causes which tend to impair his health, and prevent that sound hygienic condition necessary to make him effective and serviceable. These causos may be classed under one or the other of two heads—theso inherent in the organism of the soldier, and those external to that organism and acting upon it only from without. In the first class may bo enumerated Race, which exerts a powerful influence; the men of one race being far more subject to some diseases, and enjoying a greater immunity from others, than those of another. To a limited extent this is true even of nationalities, tho Celt, the Teuton or the Scandinavian having a constitutional predisposition to some forms of disease from which the Anglo-Saxon is free, and vice versa. In the different races of men this difference becomes strongly marked. The volunteer army of the United States is principally composed of the European or Caucasian race, some regiments being largely Teutonic, others mainly Celtic, and others, the great majority, of that conglomerate of different nationalities, the native-born American. Within a year past, however, another element has been added to the army, in the numerous regiments of African descent. The experiment has not yet progressed quite far enough to enable us to comparo the hygienic characteristics of tho two races very fully, but these facts have been ascertained: the negro troops are more subject to phthisis, scrofulous affections, and tetanus, and their wounds do not heal so readily as those of tho whites, but they are far less liable to malarious diseases, nervous affections, or the influence of the syphilitic poison than the white troops. The mortality from disease among them has been thus far proportionally much below that in tho white regiments in the departments of Tennessee, the Gulf, and the South. There are three or four regiments of Indians and halfbreeds on tho western frontier, but they are not sufficiently numerous to offer the opportunity of a fair comparison. Aye, temperament, hereditary tendencies, habit in the mode of life, morbid and vicious habits, and the natural constitution are also among the agencies inherent to tho organism which influence the hygienic condition of tho soldier, all of which must bo taken into account by the regimental surgeon who would keep the body of soldiers

under his charge in the highest effective condition. To the watchfulness of some surgeons over these agencies, ns well as those presently to bo mentioned, is due the superior conditio!) in which their regiments are always found.

But, aside from these inherent tendencies to impair the health of an army, come another class equally formidable, to assail vigor and effectiveness from without.

Of theso external agencies the most important nre the atmospheric condition, temperature, light, heat, electricity, water, soil, and locality of camp, bivouac, or barracks, the climate, and the necessary acclimation where that climate is essentially different from the one in which the soldier has previously resided, the habitation, in its plan, space, ventilation, etc., whether that habitation be a camp, barrack, or hospital; the food of the soldier in all its relations, quantity and varieties, accessary food, including condiments, spirits, tea, coffee, and tobacco, and the clothing of the army in its relations to health.

On some of these agencies a few words of explanation may be desirable. The atmosphere is an agency for the promotion or transmission of disease when loaded with moisture, especially when the temperature is low, producing at such times rheumatism, neuralgia, and often pulmonary disease. A hot and moist or a hot and dry condition of tho atmosphere is also unfavorable to health. Tho atmosphere is also a medium of imparting disease, when it is corrupted by noxious gases, when it is saturated with the effluvia thrown off by perspiration, as in over-crowded rooms, tents, etc.; when it is impregnated with the spores of fungi, or whatever it may be, which we denormnate malaria; and, perhaps, when it contains an excess or deficiency of ozone. The promotion of health in these various atmospheric conditions in the army requires the use of the rubber blanket, the protection of tents where possible, a sufficiency of good clothing, the strict avoidance and prohibition of over-crowding, whether in tent, barrack, or hospital, the careful selection of camping ground on high and dry locations, to windward of marshes or malarious positions, and, if possible, with water between the camp and the marsh; the building of fires, wherever there nre not military reasons to prevent; tho flooring of tents, and tho raising of tho floors of barracks some distance above the ground. The admini>tration of quinine or cinchonine in small doses daily to the men when exposed to malaria, is also an important prophylactic against the intermittent and remittent fevers which would otherwise prostrate so many of them.

The temperature exerts a powerful influence upon tho health of tho army. When provided with proper clothing and food, the temperature has rarely been so low as to effect serious injury upon persons in health. In a few instances, however, men in cavalry expeditions, or in transit from one point to another, where they had become very vet and were subsequently subjected to the cold in a season of immeasurable severity, have suffered from frozen extremities. With the sick or wounded when exposed the sudden accession of a low, moist temperature often proves fatal, idiopathic and traumatic tetanus supervening, and causing speedy death. Apoplexy, bronchitis, pneumonia, diarrhea, and rheumatism are often induced by it; clear, bracing, moderately cold weather is highly conducive to health. The amount of sickness is less than one half during the winter months of the summer ratio. In the army of the Potomac, in 1802, March was the healthiest month, and July the sickliest; in the army of Western Virginia, May was the healthiest and October the sickliest. In South Carolina, March was the healthiest; in Florida, December, while in July the ratio of sickness was more than five times as great. In Kansas the health of the troops was best in May, and worst in September. High temperatures are prolific in disease, unless great caution is exercised. Sunstroke is very prevalent, and to prevent it the troops should wear the Zouave tarban, or a wet folded cloth in their cap. Diseases of the liver, diarrhea, dysentery, and fevers also prevail in the hot season, and the constant care of the surgeon is requisite to ward them off.

Water is a very active agent both in promoting and in preventing disease in camps, barracks, and garrisons. In its use for drinking and cooking purposes it is absolutely essential to health that it should be at least moderately pure, and yet. it seldom is so. The water for the use of armies in the field is supplied usually from rivers or streams, from springs, or from pools or ponds, very rarely from wells or from cisterns, in which rainwater has been collected. In barracks or hospitals, cisterns, wells or reservoirs are the usual sources of supply. Rainwater, though containing somo impurities acquired from the atmosphere, or from the roofs, etc., from which it is collected, contains fewer hurtful substances in solution or admixture than water obtained from any other source. River water usually contains earthy and sometimes mineral substances, and when drawn from the vicinity of a large town has also more or less animal matter in solution. Spring water and well water also very generally contain lime, magnesia, and other mineral salts in solution, while water from pools, marshes or stagnant ponds, is largely charged with conferva) and infusoria, and is thus more injurious in its effects than any other, producing typhoid and paludal fevers, and other diseases of a grave character. The presenco of earthy or mineral substances very generally induces diarrhea, dysentery, and sometimes serious ulceration of the bowels. To prevent these evil results from the use of impure water, the surgeon of each regiment should require all water drank or used for cooking to be filtered by some one of the numer

ous simple processes in use in the army, and at permanent camps, barracks, and hospitals great care should be taken to have all the water used in the purest possible condition. The use of water in bathing and thorough ablution by the soldiers is a matter so important that it should be insisted upon wherever it is possible to obtain sufficient water for the purpose, but the time of taking the bath, the condition of the men when taking it, and the temperature, should be carefully attended to by the surgeon. Dr. Calvin Cutter, surgeon of one of the Massachusetts regiments, and for some time brigade surgeon, kept the men in his command in perfect health during the intensely hot summer of 1863, in the Department of the Tennessee, by tho strict enforcement of cleanliness and frequent bathing, the careful selection of positions for the camps, and the avoidance of unnecessary exposure to the sun. Similar care would have been rewarded, in most regiments or brigades in the field, with similar success.

The influence of soil and locality upon the health of an army is also very important. Some soils retain the heat of the sun much longer than others; this is especially the case with sandy soils as compared with those of a clayey character, or those composed of decomposed vegetable matter. The latter, on the other hand, retain moisture with great tenacity, and hence are unfitted for healthful camping grounds. A clayey soil, overlaid with gravel, is, of all others, the worst for tho site of a camp, and should never be chosen when it is possible to obtain any other. Dry, sandy positions sloping to water, to secure good drainage, with wood at no great distance, yet not overshadowing the camp, and where the sun can have access to the ground and dry up the moisture speedily, are preferable to all others. The locality should not be in a valley if it can be avoided, but rather on a hillslope—not on tho top of a lofty height, since the soldiers would be exhausted in the transportation of fuel, etc.; not on a plain unless the plain is extensive and dry.

An army going, as the army of the United States have done, to a climate warmer than that in which they had previously resided, find a necessity, if health is to be maintained, for care in diet and habits, and should as far as possible adopt the customs and food of the people of the new climate, to soenre that acclimation without which the change will be likely to prove fatal to large numbers. The food in a hot climate should be to a greater extent composed of fruits and amylaceous substances. Meat and spirituous liquors should be sparingly used in health, and coffee or tea substituted for the latter. The clothing should be adapted to the climate, and violent exercise avoided in that portion of the day when the heat is most intense. The use of anti-scorbutics and sub-acids, to avoid scurvy, is indispensable.

The habitations of the soldiers greatly in

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