Y O L 



appearing, for the evolution and fuftenance of the little 

 Embryo, lodged in a cavity of its bafe ; while the Cotyledon 

 of the not very diftant genus Zamla rtirinks indeed con- 

 fiderably, from lofing the albuminous part of its fubftance, 

 but does not difappear ; bccaufe the remaining part deflined 

 to perform the elTential office of a Cotytedon, refpefting air, 

 merely decays when its purpofc is anfwered, and floughsoff, 

 like any other dead portion of the vegetable body. 



We have already (fee Germination) adverted to thefe 

 two different iituations of the albuminous matter. That 

 fubftance muft be prefent, in fome ihape or other, for the 

 nourifhment of the young Embryo, at the firft period of its 

 evolution, when fo great an alteration of bulk takes place, 

 till it can fupply itfelf from the earth. The idea of this 

 nutritious fubftance, whether of an oily, mucilaginous, or 

 farinaceous nature, being always, when not a diftinft body, 

 lodged in the Cotyledons, throws additional light on the 

 nature and phyfiology of thefe laft-mentioned parts, and in a 

 very beautiful manner confirms their analogy with leaves. 

 The fap of plants (fee Circulation of the Sap) being 

 carried into the leaves, and there afted upon by air, light, 

 heat, and moifture, is returned in the form of various fecre- 

 tions, into the different parts of the vegetable body. Under 

 the influence of light, the upper furface of their leaves ab- 

 forbs carbonic acid gas, and the under gives out pure oxy- 

 gen. But in the dark, leaves abforb oxygen. So the Coty- 

 ledon! of feeds, in their dark fubterraneous fituation, being 

 moreover often guarded exprefsly from light by a brown 

 or even black fkin, abforb oxygen, which, as we have faid 

 in the article above cited, is known to be necefTary to ger- 

 mination. They are already ftored with albuminous matter, 

 abounding with the carbonic principle. This, by the aftion 

 of oxygen, becomes faccharine and milky, fit to be tranf- 

 mitted, through the returning veffels, which the Cotyledons, 

 in common with Leaves, poffefs, into the ftem of the Em- 

 bryo ; all thefe important parts having already begjin to 

 fwell, from the abforption of moifture, and the ftim«!ant 

 efFefts of heat. Hence we fee why light proves hurtful to 

 incipient germination, and why carbonic acid gas may be 

 given out by feeds during that procefs. It is evident that 

 the proper funftions of Cotyledons are beft performed under 

 ground, and that when they rife into the air and light, it is 

 not till after their primary deftiiiation is fulfilled, and then 

 only becaufe, being fundamentally of the nature of leaves, 

 they are moftly capable of affuming the fun£tions of thofe 

 organs, wiih refpeft to liglit. Cotyledons of feeds are fub- 

 terraneous leaves, juft like the fcales of a bulbous root. 

 Both are ftored with albuminous or nutritious matter, and 

 when afted upon by oxygen perform under ground thofe 

 funftions, which leaves perform in the open air, with the af- 

 fiftance of light. It is worthy of notice that tlie Cotyledons 

 are fo placed, in all feeds, that the oxygen gas muft be imbibed 

 by their under furface only, that very fame part which, in 

 leaves, gives out this kind of gas during the dav, and pro- 

 bably abforbs it at night. " It would," as we have elfe- 

 where obferved, Tr. of Linn. Soc. v. 9. 213, " have evinced 

 a ftrange contrariety in the conftitutions of two organs 

 Otherwife fo analogous, the Lea-ves and Cotyledons, if the 

 ■upper furface of the latter, while in the unexpanded feed, 

 had been prefented to receive the oxygen gas." 



By taking the Vltellus of Gaertner for a Cotyledon, we 

 throw no new difficulties in the way of the clafTification of 

 plants by this organ. Its form is always, as far as we 

 know, fimple and undivided, fo that the plants in which it 

 occurs remain only the more fteadily fixed in their place of 

 Monocotyledones, as oppofed to the Dlcotyledones ; witnefs 

 Gramina, Scllam'mea, &c. thus indeed acquiring a right to 



YON 



fuch an appellation, which they could otherwife fcarcely 

 claim, having, according to Gaertner's principle, no Coty- 

 ledon at all. 



YOLOTOU, or YULDUZ, or Cyalls, or Chiali/b, in 

 Geography, called by the Turks Kerafher, or the Black 

 City, a town of Little Bucharia, fituated in a country 

 abounding with fprings and fine meadows ; 85 miles N.N.W. 

 of Hami. 



YOM-NIM-KIEN Hotun, a town of Chinefe Tartary, 

 on the E. coaft of the gulf of Leao-tong ; 263 miles E. 

 of Peking. N. lat. 40°. E. long. 121° 34'. 



YOM-TA-HOTUN, a town of Corea ; 648 miles 

 E.N.E. of Peking. N. lat. 42° 55'. E. long. 129' 



37'- 



YON, a river of France, in the department of the Ven- 

 dee, which paffes by La Roche fur Yon. 



YONGHELAHE, a river of the ifiand of Madagafcar, 

 which rjins into the fea on the weft fide of the ifland, S. 

 lat. 23^ 30'. E. long. 47° 4'. 



YONG-LI, a town of Corea ; 30 miles S.E. of Koang- 

 tcheou. 



YONG-NGAN, a city of China, of the fecond rank, 

 in Quang-fi ; 1027 miles S.S.W. of Peking. N. lat. 24°. 

 E. long. 110°. 



YONG-NGAO, a fmall ifland near the coaft of China, 

 in Quang-tong ; 20 miles S.S.E. of Macao. 



YONG-NING, a city of China, of the firft rank, in 

 Yun-nan, on the borders of Thibet. A little to the E. 

 of this town is a lake ; 1095 miles S-W. of Peking. N. 



lat. 27° 50'. E. long. 100° 24' Alfo, a city of China, 



of the lecond rank, in Quang-fi; 977 miles S.S.W. of 

 Peking. N. lat. 25° 6'. E. long. 109° 14'. 



YoNG-NiNG, or Tung-ning, a city of China, of the fecond 

 rank, in Koei-tcheou ; 1027 miles S.S.W. of Peking, 

 N. lat. 25° 55'. E. long. 104' 57'. 



YONG-PE, a city of China, of the firft rank, in Yun- 

 nan ; iljo miles S.W. of Peking. N. lat. 26° 42'. E. 

 long. 100° 34'. 



YONG-PING, a city of China, of the firft rank, in 

 Pe-tche-li, on a river which runs into the gulf of Leao-tong. 

 This city is advantageoufly fituated, but its jurifdiftion is 

 not very extenfive ; it contains but one city of the fecond 

 order, and five of the third. It is environed by the fea, by 

 rivers, and by mountains, covered for the moft part with 

 fine trees : this makes the country lefs fertile, but the 

 neighbouring bay fupplies its want with great plenty of all 

 the neceffaries of life. Not far from this city ftands a fort 

 named Chun-hat, which is the key of the province of Leao- 

 tong. This fort is near the beginning of the great wall, 

 which is built, for a league together, in a boggy marfh, 

 from the bulwark in the fea; iij miles E. of Peking. 

 N. lat. 39° 55'. E. long. I iS^ 34'. 



YONG-SIN, a town of Corea; 113 miles E. of Han- 

 tcheou. 



YONG-TCH ANG, or Yung-tchang, a city of China, , 

 of the firft rank, in Yun-nan. This city is large and popu- 

 lous, and is built in the midft of high mountains, on the 

 borders of the province, in the neighbourhood of a favage 

 people, whnfe genius and manners the inhabitants of this 

 country partake of. The country produces gold, honey, 

 wax, amber, and a vaft quantity of fine filk. It has within ; 

 its diftrifts one town of the fecond order, and two of the 

 third ; 270 miles S.W. of Peking. N. lat. 25° 6'. E. 

 long. 99°. 



YONG-TCHEOU, a city of China, of the firft rank, 

 in Hou-quang ; 882 miles S.S.W. of Peking. N. lat. 

 26° 10'. E. long, hi" 15'. 



YONG- 



I 



