GRA 



GR A 



■works, for the purpose of concentrating 

 the brine, by allowing a shower of it to 

 trickle over fagots. 



GRAFTING. The horticultural ope- 

 ration by which a portion of one plant is 

 so applied to another plant that a vital 

 union may take place between them ; 

 the portion so applied, is called the scion ; 

 the rooted plant to which it is applied, is 

 the stock or stem. There are various 

 modes of grafting, which have received 

 the names of whip, cleft, saddle, and 

 crown grajting. 



Grafting by approach, or Inarching, is 

 a mode of grafting, by which the scion is 

 not separated from its parent plant, until 

 it has become vitally united to the stock. 

 GRAINER. The ley obtained by the 

 infusion of pigeon's dung in water, era- 

 ployed for imparting flexibility to skins 

 in the process of tanning. 



GRALLATO'RES ( grall^e, stilts). 

 Waders, or Stilt-birds ; an order of aquatic 

 birds frequenting marshes, and named 

 from their being raised on their long legs, 

 as on stilts. They comprise the heron, 

 the snipe and woodcock, the rail and 

 coot, and the plover. 



GRAMINA'CE^ {gramen, grass). 

 The grass tribe of Monocotyledonous 

 plants. Herbaceous plants with cylin- 

 drical stems; leaves alternate, with a 

 split sheath ; flowers hermaphrodite, 

 sometimes monoecious, glumaceous ; 

 glumes alternate, unequal; stamens hy- 

 pogynous ; ovarium simple. 



GRAMMAR {ypaufxa, a letter). That 

 branch of science which relates to the 

 component parts of language, and em- 

 braces the subjects of orthography, ety- 

 mology, syntax, and prosody. 



GRA'NITE {granum, a grain). An 

 unstratified or igneous, coarse, granular 

 rock, occurring generally beneath, or 

 associated with, the oldest of the strati- 

 fied rocks, and sometimes penetrating 

 them in the form of dikes and veins. It 

 commonly consists of three simple mine- 

 rals — quartz, felspar, and mica. Several 

 varieties of granite have received dis- 

 tinctive names, as the porphyritic, the 

 graphic, the schorly, the talcose, and the 

 hornblendic. 



GRANI'VORiE (^rrawMW, agrain, voro, 

 to devour). An order of birds, including 

 the Insessores, which feed on grains. 



GRANULA (dim. ot granum, a grain). 



Little grains, a term applied to the large 



sporules continued in the centre of many 



Algaceous plants. 



GRA'NULATED {granulatus, grained). 



155 



Grained ; marked by elevated, closely- 

 set, regular grain-like dots ; an appear- 

 ance very common at the base of the 

 predacious spiral genera of mollusca. 



GRANULATION [granum, a grain). 

 The division of a metallic substance into 

 grains or minute particles, for the pur- 

 pose of facilitating chemical combination ; 

 it is performed by pouring the metal into 

 water, or by agitating it in a closed vessel 

 until the moment of congelation, when it 

 falls into powder. 



GRA'PHIC GRA'NITE. A modifi- 

 cation of granite, which derives its name 

 from its presenting, when polished, some 

 appearance of written characters. See 

 Granite. 



GRAPHIC ORE or GOLD. An ore 

 of tellurium, occurring in veins in por- 

 phyry, in Transylvania, and consisting of 

 tellurium, gold, and silver. 



GRAPHITE (7pa0a), to write). Plum- 

 bago or black-lead ; a carburet of iron, 

 named from its use in writing. Compact 

 graphite occurs at Borrowdale in Cum- 

 berland, in beds of variable thickness, 

 included in a bed of trap, which is sub- 

 ordinate to clay-slate. Artificial graphite 

 is produced by placing an excess of char- 

 coal in contact with fused cast iron. 



GRAPSOIDIANS. A tribe of bra- 

 chyurous crustaceans, named from the 

 genus grapsus, and placed by M. Milne 

 Edwards, near the Gonoplacians. 



GRA'PTOLITE {^panro?, written, 

 Xi0of, a stone). A fossil sertularian co- 

 ralline, one of the most simply organized 

 of the Silurian species, consisting appa- 

 rently of the horny skeletons of animals 

 resembling those found on the coral and 

 sea- weed of our own coast. By this term 

 Linnaeus designated those stones which 

 are marked with various forms, repre- 

 senting buildings, vegetable structures, 

 as ruin marble, moss-agate, &c. 



GRAVFMETER {gravis, heavy, jue- 

 rpov, a measure). An unclassical term, 

 adopted by M. Greyton in preference to 

 hydrometer or arceometer, because these 

 terms imply that the substance weighed 

 is a liquid, whereas, when solids are 

 weighed, the liquid is only the term of 

 comparison to which the unknown weight 

 is referred. 



GRAVITATION (gravitas, weight). 

 This term has been suflSciently explained 

 under the head of Attraction. The laws 

 of gravitation, as laid down by Newton, 

 and universally admitted, are as follows : 

 — The gravitating forces of bodies are to 

 each other, 1, directly as their masses • 

 H6 



