H E M 



of a glafs plate, whofe increafe in length would ferve as a 

 meafurc of temperatures. 



Table III.— Expanfton of Mel ah. 



ratun- 

 deduc'ti 

 from till- 



lion ol 

 A;r. 



lOO" 

 300 



Meanab 

 fjliite 



Dilata- 

 liun of 

 Iron. 





Tempera- 

 ture iddl- 

 c.itetl by a 

 Therino- 



meier 

 made ufa 

 BjroFliun, 



100" 

 372.6 



Mean ab- 

 l"i)lmeDi- 

 iaiatiofui) 

 Copper. 



TSTSS 



Tempe- 

 rature in- 

 dicated 



by a 

 Thermo- 

 meter 

 made of a 

 Copper 

 Uod. 



100" 

 328.8 



Mean ab- 

 folute Di- 

 latation of 

 Platinu 



Tenipera- 

 ture indi- 

 cated ijy a 

 Thermo- 

 meter 

 made of a 

 Platina 

 Rod. 



100 

 3II.6 



When we compare thefe refults with thofe obtained from 

 glafs, it is feen that the cxpanfibility of folids referred to an 

 air-thermometer is increafing, and that it is unequally fo in 

 each of them. 



Our readers will obferve, that MM. Dulong and Petit 

 ufed the centigrade thermometer. See further on this fub- 

 ]eSi under REFiUGERATroN. 



See an Eflay which gained the prize voted by the Aca- 

 demy of Sciences in 181 8, entitled Refearches on the Mea- 

 fure of Temperatures, and on the Laws of the Communica- 

 tion of Heat, by MM. Dulong and Petit. 



Aiur:<al Heat. — The above determinations of the fpecific 

 heats of oxygen gas and carbonic acid by Delaroche and 

 Berard, very much diminifh the probability of Dr. Cravf- 

 ford's theory of animal heat. But the moft formidable objec- 

 tions to this theory refult from the experiments of Mr. 

 Brodie. This gentleman found that when artificial refpira- 

 tion is kept up in the lungs after decapitation, the ufual 

 proportio.i of carbonic acid gas is formed, and the circula- 

 tion continues nearly as ufual, yet tliat in thefe animals the 

 heat diminilhes more rapidly than in the dead animal in 

 which artificial refpiration is not kept np. From thefe 

 experiments, Mr. Brodie concludes that the produftion of 

 animal h.eat is owing to the aftion of the brain, and not to 

 refpiration. See Respi RATION. 



HEATH, in Geography, a town of Hampfliire, in Maf- 

 fachufetts, containing 917 inhabitants. 



HEAVY Spar. See Mineralogy, Jifdenda. 

 HEBRON, 1. 2, r. 563 ; 1. 3, r. Oxford for Cumber- 

 land; 1. 5, add after Portland — containing 1211 inhabi- 

 tants ; 1. 8, r. 2002. 



HEIDELBURG, I.4, r. 3532 ; 1. 6, r. 1433. Add 

 — Alfo, a townfliip in Pcnnfylvania, in Berks county, having 

 2808 inhabitants. 



HEITSBURY, col. 2, at the clofe, r. the population of 

 the borough and parifli, returned in the year 1 8 1 1 , was 1 023 ; 

 the number of houfes 198. 



HELEN'S, St., 1.9, r. 106—658. 

 HELLAM, a townihipof Pennfylvania,in York county, 

 having 141Q inhabitants. 



HELLENLSTS, col. 2, 1. 24, r. Hellenism. 

 HELMSLEY, 1. 5, r. 181 1— 261 ; 1. 6, r. 1415. 

 HELSTON, col. 2, 1. 2, r. 2297-328. 

 HEMATIN, in Chem'iftry, the naine given by Chevreul 

 to the peculiar matter conftituting the colouring matter of 

 the hiematoxyton campech'ianum, or logiuood. 



Hematin may be obtained by digefting, for feveral hours, 

 logwood-powder in water, of the temperature 125^. The 

 liquid is then to be filtered, evaporated to drynefs, and di- 



H E R 



gefted for a day in alcohol of the fp. gr. .837. Filter the 

 alcohol, concentrate it by evaporation, then add a little water, 

 evaporate a little further, and leave it to itfelf. Cryilals of 

 hematin are depofited in abundance. Thus prepared, it is 

 in the form of fmall brilliant cryilals, of a reddiih-white 

 colour, and a flightly aftringent bitter and acrid taile. It 

 is readily foluble in boihng water, and the folution is of an 

 orange-red colour when warm, which becomes yellow as it 

 cools, but heat again reilores the original colour. Acids 

 render it at firll yellow, then red ; fulphureous acid dellroys 

 it altogether. The alkalies and alkaline earths give it a 

 purplifh-red colour, and if in excefs appear to decompofeit. 

 Moll of the metallic oxyds unite with hematin, and give it 

 a blue colour. Gelatine throws it down in reddifh flocks. 

 The other properties of this fubftance do not appear remark- 

 able. 



HEMEL-HEMSTED. At the clofe,infert— The popu- 

 lation of the parifli, by the return of 181 1, amounted to 

 3240, and the number of houfes to 638. 



HEMIONUS. See Equus. 



HEMLOCK, in Geography, a townfhip of Northumber- 

 land countv, in Pcnnfylvania, having 879 pcrfons. 



HEMPFIELD. Add— The former contains 3431, and 

 the latter 3444 inhabitants. 



HENDERSON, in Kentucky, 1.2, r. 4544 ; 1. 3, r. 

 1467. At the clofe, add — containing 159 perfons, of whom 

 47 were flaves in 18 10. 



HENLEY-7//o/7-77iaOTfj, 1. «//. r. 181 1 — 522 — 3117- 



Henley m Arden, 1. 5, r. 181 1 — 242 ; 1. 6, r. 1035. 



HENNHvER, a town of Hillfljorough county, in New 

 Hampfliire, having 1608 inhabitants. 



HENRICO, 1. 2, r. 9945 ; 1. 3, 4846. 



HENRY, 1. 4, r. 5611 inhabitants, of whom 1755 were 

 flaves in 18 ID ; 1. 6, ;-. 6652 inhabitants, of whom 1103 were 

 flaves. 



HEPATICA, in Botany, fo named by the earlier bo- 

 taniils and phylicians, from a refemblance in the lobes of the 

 leaves to thofe of the human liver, is reilored as a diilinft 

 genus from Anemone, (fee that fupplementary article,) by 

 profeflk)r De Candolle, in his Syil. v. i. 215, merely becaufe 

 the involucrum is placed very near to the flower, ( fome have 

 thought it an atftual perianth), and its leaves undivided. We 

 helitate to follow our learned friend in this meafure, the 

 certain fpecies of Hepatica being fcarcely more than one or 

 two, fo that nothing is gained as to convenience, nor is the 

 charafter very decifive. Thefe fpecies are, 



1. H. triloba. Common Hepatica. (Anemone Hepa- 

 tica ; Linn. Sp. PI. 758. Sm. Fl. Grxc. Sibth. t. 5 1 3, 

 unpubliflied. Fl. Dan. t. 610, notffi2.) — Leaves heart- 



fliaped, with three entire lobes Native of Europe and 



North America. A common hardy garden plant, with blue 

 pink, or white, fingle or double, very early, bloflbnis. The 

 fynonyms are numerous. De Candolle by a cafual error 

 cites Engl. Bot. t. 51. 



2. H. angulofa. Angular, or Serrated, Hepatica. La- 

 marck Dift. v. I. 169. — Leaves palmate, with five ferrated 

 lobes. Cultivated formerly at Paris, but now loft;. It is 

 much to be wiflied that we could learn more concerning this 

 plant. 



3. H. integr'tfolia, with ovate entire leaves and very hairy 

 ftalks, found by baron Humboldt in South America, is not 

 clearly an Hepatica. 



HEPATITE. See Mineralogy, Addenda. 



HERAT. Add — The ancient Aria or Artacoana, 

 capital of Ariana ; 1. 4, after name, infert — or Herirood ; 

 1. 5, after which, add — gives fertility to the plain, 30 miles 

 long and 15 broad, upon which Herat is fituated, and 



wliicli, 



