GELDING. 



GEOLOGY. 



water cools ; and it may be repeatedly liquefied 

 and again gelatinized by the alternate applica- 

 tion of heat and cold. Isinglass, glue, and 

 size are various forms of gelatin, the first be- 

 ing this substance in a very pure state, obtained 

 by washing and drying the swimming bladder 

 of the sturgeon (jicipenser huso) and some other 

 fish. Its most distinctive chemical character 

 is the formation of a dense white precipitate 

 when its solution in warm water is poured into 

 an infusion of galls, or that of any other as- 

 tringent vegetable; the substance formed in 

 such cases is a tannate of gelatin, by the 

 union of the tanic acid with the gelatin. Ge- 

 latin is semi-transparent and colourless when 

 pure. Its consistency and hardness vary con- 

 siderably. The best kinds are very hard, brittle, 

 and break with a glassy fracture. Its taste is 

 insipid, and it has no odour. A solution of 

 one part of gelatin in 5000 of water is ren- 

 dered slightly turbid by the addition of a strong 

 infusion of galls. Gelatin, as an article of 

 food, is not so nutritious as is generally sup- 

 posed. 



The ultimate components of gelatin are 



Carbon 

 Hydrogen - 

 Nitrogen 

 Oxygen 



Parti. 



- 47-8 



- 7-9 



- 16-9 



- 27-4 



100- 



100 Ibs. of bones yield about 25 or 27 Ibs. 

 of gelatin. It is used for making carpenter's 

 glue, as the fat in the bones gives it a bad 

 taste, and renders it unfit for soup. See GLUE. 

 (Brande's Diet, of Science.) 



GELDING. In farriery, a castrated animal; 

 and also the act of castrating. In performing 

 this operation, attention should be paid to the 

 age, and also the season of the year. The most 

 proper seasons are either the early spring 

 months, or those of the autumn. 



GENTIAN (Gentiana). This, in England, is 

 an extremely beautiful genus of plants; the 

 roots of which form one of the principal bit- 

 ters of European growth. The stems and 

 roots of most of the species, especially the 

 autumnal gentian (G. amarella), the field gen- 

 tian (G. canipestris), and some of the foreign 

 species are tonic, stomachic, and febrifuge. 

 That which is principally used in medicine is 

 the root of the great yellow gentian (G. lutea), 

 which is imported from Germany. The gene- 

 ric name was given to them after Gentius, 

 King of Illyria, who is reported to have first 

 experienced the virtues of the plant. The 

 species of gentian, indigenous to England, ac- 

 cording to Sir J. E. Smith, are six in number. 



1. The Marsh Gentian or Calathian violet 

 (G. pneumonanthe). A perennial herb, found 

 on moist, turfy heaths, blooming in August and 

 September. 



2. The Dwarf Gentian (G. acaulis). A pe- 

 rennial, but very doubtful native, found on 

 mountains. The stems generally very short, 

 rising from the centre of tufts of leaves, single- 

 floxvered. The flower, which blows in June 

 or July, is large, often two inches long, ex- 

 quisitely beautiful, of a rich blue in the limb, 

 paler in the tube, which is dotted internally 

 with black. Root fleshy and branching. 



530 



3. The Spring Gentian (G. wrna). A peren- 

 nial, growing in barren, mountainous situations, 

 but rare, flowering in April. 



4. Small Alpine Gentian (G. nivalis). An 

 annual found on the loftiest mountains of Scot- 

 land. 



5. The Autumnal Gentian (G. amarella). An 

 annual plant, growing frequent in limestone 

 and chalky pastures, flowering in August and 

 September. 



6. The Field Gentian (G. campestris). An 

 annual, flowering in September or October, 

 growing on elevated pastures, or upon green 

 hills towards the sea-coast, where the soil is 

 chalky or gravelly. The roots are very bitter 

 and tonic. It is sometimes known as yellow 

 centaury and blue gentian. 



Most of the herbaceous kinds of gentian 

 grow well in a rich, light soil, but some re- 

 quire to be growfl in peat; indeed, all will 

 grow much stronger in it. Several of the 

 species should be grown in pots, placed among 

 alpine plants, and protected in winter. Some 

 of them may be increased by divisions. The 

 annual and biennial kinds may be sown in a 

 dry, sandy situation in the open border ; but 

 they must be sown as soon as the seeds are 

 ripe, because, if left till spring before they are 

 sown, they will not, very probably, come up 

 till the second year. 



The species of gentian best known in the 

 United States, are : 1. The one called Soap- 

 wort (G. saponaria), a handsome plant, fre- 

 quently found in Pennsylvania and other 

 Middle States, along the margins of swampy 

 rivulets and in low grounds. It flowers in 

 September, and ripens its seed in November. 

 The root, as in all the genus, is bitter and tonic. 

 2. Yellowish-white Gentian (G. ochrolcuca), 

 found in fields and woodlands in the Middle 

 and Southern States, but not so common as the 

 former kind. 3. Haired, or Fringed Gentian 

 (G.crinita), frequent in hilly, open woodlands 

 and old fields in Pennsylvania, where it is one 

 of the most beautiful autumnal flowering 

 plants in the months of September and Oc- 

 tober. Its flowers are often destroyed by frost. 

 Though generally described as a biennial, Pro- 

 fessor Eaton considers it a perennial. Dr. 

 Darlington thinks it an annual. 



Seven or eight additional species of gentian 

 are enumerated in the United States. (Flora 

 Cestrica.) 



GEOLOGY (>, the earth; x>o f , a dis- 

 course). The use of this science to the culti- 

 vator is considerable. The farmer is, in fact, 

 obliged to vary his modes of tillage with the 

 different strata which he tenants, and hence he 

 is often following in practice the very rules, 

 and observing the laws which the science of 

 geology would prescribe, without being aware 

 of the scientific reasons by which his labours 

 are guided. It is a science he will find closely 

 connected with the best modes of cultivating 

 the soil, the drainage of land, the mixture of 

 earths, and other agricultural improvements. 

 From geological observations, the farmer 

 learns the process by which the soils he culti- 

 vates were originally formed, their connexion 

 with the substratum, and the readiest mode of 

 improving their constituents; thus, as it is 



