G E H 



[ 187] 



G E 



indented and palmated, like those 

 of the crocodiles proper. 



The living species of the crocodile 

 family are thirteen in number. 

 Teeth of the fossil gavial have been 

 found in the Tilgate strata. Dr. 

 Mantell observes, " it appears that 

 the strata of Tilgate Forest contain 

 the remains of at least two, if not 

 four, species of crocodiles : that one 

 of these (that with slender curved 

 teeth) resembles the gavial of Caen, 

 and probably was about twenty-five 

 feet in length." 



GE'HLENITE. A mineral allied to 

 Vesuvian, and so named after 

 Gehlen. A combination of silica, 

 alumina, lime, and oxide of iron. 

 It occurs in rectangular four-sided 

 prisms, nearly approaching in their 

 dimensions the form of a cube; 

 sometimes isolated, generally in- 

 vested by calcareous spar, aggre- 

 gated irregularly in groups, or 

 massive, including pleonaste. Col- 

 ours : various shades of grey, green, 

 and brown. Surface : commonly, 

 rough and dull ; when sufficiently 

 brilliant for the use of the reflective 

 goniometer, the crystals afford 

 angles of 90 in every direction. 

 Before the blow-pipe, when alone, 

 it is but little affected, with borax 

 it fuses into a glass coloured by 

 iron. Heated in muriatic acid, it 

 gelatinizes. Prof. Phillips. 

 GE'LATINE. j (gelee, Pr. gelatwa, It.) 

 GE'LATIN. j A concrete animal sub- 

 stance ; the principle of jelly. If 

 a piece of the fresh skin of an ani- 

 mal, after every impurity is care- 

 fully separated, be put into a 

 quantity of cold water, and boiled 

 for some time, part of it will be 

 dissolved. Let the decoction be 

 slowly evaporated till it is reduced 

 to a small quantity, and then put 

 aside to cool. When cold, it will 

 have assumed a solid form, and 

 precisely resemble that tremulous 

 substance known as jelly. This is, 

 what is called by chemists, gelatin. 



If the evaporation be carried far- 

 ther, the substance becomes hard, 

 semitransparent, breaks with a 

 glassy fracture, and is, in short, 

 that substance known under the 

 name of glue. Gelatine therefore 

 is the same with glue, only that it 

 is free from those impurities with 

 which glue is so often contaminated. 

 Gelatine is colourless and trans- 

 parent; when thrown into water 

 it soon swells, and assumes a gelat- 

 inous appearance, and gradually 

 dissolves away. By evaporating 

 the water it may again be obtained 

 unaltered in the form of jelly. 

 Cold water dissolves it slowly, but 

 water at a temperature of 90 rap- 

 idly. Gelatin is insoluble in al- 

 cohol. 

 GEM. (gemma, Lat.) 



1. In mineralogy, any precious 

 stone. Gems may be divided into 

 natural and artificial; the latter 

 are made of what is termed paste, 

 coloured with different metallic 

 oxides. 



2. In botany, the bud, a small 

 conoid body, covered with scales, 

 formed during summer on the 

 branches of trees, containing the- 

 rudiments of a future plant, or part 

 of a plant : some buds produce 

 flowers and leaves, others leaves 

 only, and some flowers only. 



GE'MINATED. In conchology, marked 

 with a double elevated strias con- 

 necting the wreaths. 



GE'MINOUS. (geminus, Lat.) Double ; 

 in pairs. 



GE'MMIPAEOTTS. Producing buds, or 

 gems. The animals forming the 

 class Poriphora are gemmiparous. 



GE'MMULE. A little bud. 



GENE'EIC. } (g6n6rique,l?ic.gen6rico t 



GENE'BICAL. j It.) That which 

 comprehends the genus, or distin- 

 guishes from another genus, but 

 does not distinguish the species. 



GENI'CULATE. } (geniculatus, Lat.) 



GENI'CTJLATED. j Knotted ; jointed . 



