ERA 



Equi- 

 valent*, 

 Hydro- 

 gen = 1. 



43. Strontium 



44. Sulphur . 



45. Tellurium 



46. Thorium . 



47. Tin. . . 



48. Titanium . 



49. Tungsten 



50. Vanadium 



51. Uranium 

 62. Yttrium . 



53. Zinc . . 



54. Zirconium 



24 

 100 

 68 

 217 

 32 

 32 

 30 



Equi- 

 valents. 

 Oxyxen 



5-5 



2' 



4" 



7-5 



7-25 



3" 

 12-5 



8'5 

 27-12 



4- 



4' 



375 



The foregoing enumeration may again be 

 very properly subdivided and classified 

 according to their analogies, as the greater 

 number of them fall under the character 

 of metals. Some, therefore, have been 

 called metalloids, as only in certain re- 

 spects they resemble metals, but in others 

 are greatly different ; others, again, by 

 entering into peculiar and distinct saline 

 combinations, have been termed halogens, 

 of which common salt is the type ; while 

 a third class have been designated gazo- 

 lytes, having never been either liquefied 

 or solidified, but when isolated always 

 presenting themselves in the form of per- 

 manent gases. The following, there- 

 fore, Is the classification adopted by Ber- 

 zelius: 



I. II. III. 



Metalloids. Halogens. Gazolytes. 

 Sulphur. Chlorine. Oxygen. 



Phosphorus. Iodine. Hydrogen. 



Carbon. Bromine. Kitrogen. 



Boron. Fluorine. 



For the classification of metals, see METALS. 

 EQUIVALVE. In conchology (from eequus 

 and valva), a term applied to bivalves 

 when the valves are found exactly alike 

 as to their length, width, depth, &c. : op- 

 posed to inequivalve. 

 EOTJU'LEUS, 1 In astronomy, the little 

 EQUIC'ULUS, or \ horse ; one of Ptolemy's 

 E'auusMiNOR. j constellations. Also, 

 Eqwileus signifies a species of rack used 

 as an instrument of torture. 



E'QUUS, the horse; a genus of solipede 

 quadrupeds : family Pachydermata ordin- 

 aria, Cuv., E. caballus, the horse, properly 

 so called ; E. hemionus, the dzigguetai of 

 Central Asia ; E. asinus, the ass, a native 

 of Central Asia also ; E. zebra, the zebra 

 of the South of Africa ; E. quaccha, the 

 quagga of South Africa; E. montanus, the 

 onagga of Africa; E. marinus, Lin., the 

 sea-horse or walrus. 



ERA., Lat. eera; a particular reckoning 

 of time, counting from some remarkable 

 epoch. (The terms epoch and era are 



'2 E R M 



frequently confounded, both in speaking 

 and writing's. 



ER'ASED. In heraldry, an epithet for 

 the head or limb of a creature violently 

 torn from the body, so as to give it a 

 jagged appearance. 



ERAS'TIASS, the followers of Erastus, a 

 German divine. 



ER'ATO, e^uj,love. In ancient mythology, 

 the muse who presided over love poetry. 



EREC'TILE, from erigo, to set upright ; a 

 term applied to a tissue peculiar to some 

 parts of the animal body, as the nipples, 

 lips, iris, &c. It is formed of veins, ar- 

 teries, and nervous filaments. 



ERECT'OR. In anatomy, a muscle, the 

 ofllce of which is to erect or raise the part 

 into which it is inserted. 



ERETHI'SM, from tftS^M, to irritate, 

 preternatural sensibility of the animal 

 system. 



ER'OOT, Fr. ergote, a spur. In farriery, 

 a stalk like a piece of soft horn, situated 

 behind and below the pastern joint. In 

 agriculture, a black curved morbid ex- 

 crescence, like the spur of a fowl,.found 

 in the spike of the rye (Secale cerealis, 

 Lin.), especially in hot climates, when 

 great heat suddenly succeeds to much 

 moisture. The disease is caused by a 

 small insect which penetrates the grain, 

 feeds on its amylaceous part, and leaves 

 its poison in the parenchyma. The ex- 

 crescence is extensively used in medicine, 

 under the name of the ergot of rye. 



ERI'CA, the heath ; a genus of permanent 

 plants, of which Don enumerates 402 dis- 

 tinct species, besides varieties. Octan- 

 driaMonogynia. There are two British 

 species, the Cornish and common heath, 

 or ling, of which however there are many 

 varieties. Almost all the other species 

 are greenhouse plants. 



ERID'ANCS, \ a constellation of the 



THE RIVER Po, ) southern hemisphere. 

 This immense constellation is fabled to 

 derive its name from Phaeton's tumbling 

 into the river Eridanus or Po. It contains 

 84 stars, of which Achernar is the most 

 brilliant. Its course winds from Orion to 

 Cetus, and thence to Phoenix. 



ERINA'CETJS, the hedgehog ; a well- 

 known genus of insectivorous mammalia. 

 One species is common in the woods and 

 hedges of Europe. It eats fruit as well 

 as insects. Its skin was formerly used to 

 dress hemp. 



ERIOM'ETER, from tqitg, wool, and 

 /u-trgav, measure ; an instrument for mea- 

 suring the fibres of wool, &c. 

 j ER'MINE. 1. In zoology, a species of 

 weasel, the Mustila Candida, Lin., abun- 

 I dant in all cold countries, especially Rus- 

 sia, Norway, and Lapland. In summer 

 it is brown, and is then called the stoat, 

 but in winter it is snowy white, and iU 



