HEIGHTS HEINECKKN. 



669 



Since Deluc's discovery, the remarkable formula 

 proposed by the author of the Mvcanique celeste (vol. 

 iv. p. 289) is the most distinguished discovery on this 

 subject. (See Puissant's Geodesic, vol. ii. and Biot's 

 Astron., vol. iii.) He reduced to a certain point, in 

 a more natural and simple manner, all the corrections 

 which are to be made, on account of the influence of 

 temperature, of moisture and gravity on the mercury 

 and the air. lie rested his theory on the most ac- 

 curate data; but the coefficient which he had assum- 

 ed, in order to represent the relation between the 

 weight of the atmosphere and that of the mercury, 

 appeared to have too little foundation : the formula 

 was to be proved ; the length of the columns to be 

 substituted for their weight ; many causes of errors 

 remained to be ascertained ; the coefficient was to be 

 improved, or, rather, a new one was to be determin- 

 ed. Ramond has done all this. By a comparison 

 between barometrical observations, and actual 

 measurements of the heights where the observations 

 were taken, he has determined the coefficient, as it is 

 contained in Laplace's last formula. Ramond and 

 many other observers have shown, by experiment, 

 that this formula is not only adapted to small as well 

 as great heights, but is also useful in taking measure- 

 ments under the surface of the earth. 



Barometrical observations may attain great accur- 

 acy, when they are made with good instruments, by 

 good observers, and under favourable circumstances. 

 In order to ascertain the relative height of two points, 

 two barometers and four thermometers are requisite ; 

 two of the thermometers being attached to the baro- 

 meters, and two of them being free. These instru- 

 ments must be as simple as is consistent with conveni- 

 ence and accuracy ; and they must agree perfectly. 

 The observers must be well acquainted with their in- 

 struments, in order to be able to use them ; and it is 

 particularly necessary that they should know on what 

 the observations depend. If two or more observers 

 undertake to ascertain the elevation of a place or 

 country by barometrical measurement, they must at- 

 tend especially to the following particulars : a, that 

 the instruments hang perpendicularly, protected from 

 the sun, and that the free thermometers be raised, at 

 least, nine feet from the ground, and from any objects 

 which might have an influence on their temperature; 

 6, the barometers should be accurately regulated, 

 and the degree at which the mercury stands in the 

 barometer and thermometer should be carefully not- 

 ed ; and, c, after the instruments are made to corre- 

 spond, the observations should be made contempor- 

 aneously : finally, the observer must be particularly 

 careful to note the state of the atmosphere. Observa- 

 tions should not be taken in stormy weather, or when 

 the quicksilver in the barometer is liable to sudden 

 variations ; moderate weather, when the atmosphere 

 is either calm, being clear or cloudy, or when there 

 is a light wind, is the most suitable time for making 

 observations. The instruments should not be at too 

 great a distance from each other. The greatest in- 

 tervening space should not exceed ninety miles. If 

 these general rules for measuring heights by the 

 barometer are attended to, it is far preferable to every 

 other instrument, to ascertain, expeditiously, the 

 height of a mountain, the descent of a river, &c., for 

 a certain space; the relative height of different points, 

 the depth of a cavity, and the thickness of the strata 

 of a mountain. We cannot, indeed, ascertain the fall 

 of a river to an inch by barometrical measurement ; 

 but, by careful observations, we may come very near 

 the truth. 



Tables founded on Laplace's formula, give great 

 facility in calculating these observations. Among 

 many others, Tables hypsometriques (Paris, 1809) 

 are particularly good, on account of their correctness 



and adaptation for use. Also the tables by Gauss, 

 published, 1818, in Bode's Astronom. Jahrbuch, are 

 to be commended for their brevity, though one must 

 also have at hand the usual logarithmic tables. 

 Biot's Tables barometriqucs (Paris, 1811) are not less 

 excellent. The labours of the distinguished natural 

 philosopher and mineralogist D'Aubuisson (1809), the 

 progress and result of which are detailed in a memoir 

 read before the mathematico-physical class of the 

 institute, at Paris, March 26 and April 9, 1810, are 

 particularly worthy of notice. 



HEILIGEN (from heilig, German for holy); a word 

 in many geographical names ; as Heiligenstadt. 



HEIM ; the root of many German words, and a 

 syllable appearing at the end of many geographical 

 names, signifying home (with which it has a common 

 origin) or dwelling; as Manheim. The Swedish hem 

 signifies the same thing ; also the English ham, in 

 Durham, &c.; and the French hameau is derived from 

 it. 



HEIM, PETER PETERSEN ; a man of obscure origin, 

 who, by his bravery, rose to the dignity of high 

 admiral of Holland. He was born in 1577, rose gra- 

 dually to the rank of vice-admiral of the East Indian 

 fleet, and, three years afterwards, received the chief 

 command. He attacked the Portuguese, in 1626, 

 on the coast of Brazil, took several ships, and carried 

 home a rich booty. The same year, he captured the 

 Spanish plate fleet, and obtained an immense booty. 

 In 1629, he was appointed high admiral in reward 

 for his services; and was soonafter killed in an engage- 

 ment with a fleet from Dunkirk, of which he had 

 already captured three ships. 



HEINECCIUS, JOHN GOTTLIEB; a German author, 

 who wrote on logic, jurisprudence, and ethics. He 

 was born in 1680, at Eisenberg, and studied at Halle, 

 where he afterwards obtained a professor's chair in 

 the sciences of philosophy and law. In 1724, he 

 quitted Halle for Franeker, and remained there till 

 1727, when he accepted an invitation, given him by 

 the king of Prussia, to settle at Frankfort on the 

 Oder. Here he resided upwards of six years, when he 

 returned to Halle. His works were collected and 

 published at Geneva, in eight quarto volumes, 

 three years after his decease, which took place in 

 1741. The principal are, Syntagma Antiquitatum 

 Romanorum Jurisprudentiam illustrantium ; Ele- 

 menta Juris Civilis; Elementa Philosophies Rationalis 

 et Moralis ; Historia Juris Civilis ; Elementa Juris 

 Natures et Gentium (translated into English by 

 Turnbull); Fundamenta Styli cultioris; and several 

 academic dissertations. 



HEINECKEN, CHRISTIAN HENRY, a child greatly 

 celebrated for the premature development of his 

 talents, was born at Lubeck, Feb. 6, 1721. He 

 could talk at ten months old, and had scarcely com- 

 pleted his first year, when he knew and recited the 

 principal facts in the five books of Moses, and, at 

 fourteen months, knew the history, both of the Old 

 and New Testament. At two years and a half, he 

 could answer questions in geography, and in history, 

 ancient and modern ; soon after, he learned Latin and 

 French. In his fourth year, he had learned the doc- 

 trines of divinity, with their proofs from the Bible ; 

 modern history ; ecclesiastical history; the institutes ; 

 200 hymns, with their tunes ; and 1500 verses and 

 sentences from the ancient Latin classics. His stu- 

 pendous memory retained every word repeated to 

 him ; and, at the court of Denmark, he delivered 

 twelve speeches without once faltering, and under- 

 went public examinations on a variety of subjects. 

 He spoke German, Latin, French, and Low Dutch. 

 He was exceedingly good natured and well behaved, 

 but of a most tender and delicate constitution. He 

 never ate solid food, but chiefly subsisted on liu 



