Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/798

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and the purflain, but with this difference, that the Iettice leaves were not nearly of the fize of thofc growing in the open aii j whereas thofe of the purflain and crefles were of the fame fize. The purflain lived only one day in the receiver, and the crefles only five; after this their leaves became black, and flaccid; the Iettice continued vigorous fifteen days. In all this time the chervil and parfley had not germinated at all, on which Mr. Romberg was defirous to fee what was the ftate of thofe feeds, which had not germinated, under the fame circumftances in which others had, and whether they would germinate in the open air after they had refufed to do it in the exhausted receiver ; but that the trial might be confined to the fame circumftances only, he determined to keep them clofed up in the fame receiver, only filling it with air. He let in the air on the twenty fifth of May, and carefully clofed the veffel ; and on the twenty feventh, there appeared fome germinations of chervil, and fome frefh ones of purflain and crefles, and on the thirty firft of the fame month there ap- peared above twenty germinations of the parfley. The fol- lowing days produced no new germinations ; and Mr. Hom- berg, to try whether thofe fhoots which had appeared in a clofe air would live in an open one, removed the box out of the receiver into the open air, when in a few days all the fhoots withered and decayed, though carefully watered every evening.

Therchappcned alfo a remarkable change in the earth in the box on this expofure ; it was of the fine mould from the king's gar- den, and for the nrft five days it fbewed no appearance of change, but on the fecond watering on the iixth day, when the air came to be exhaufted from among that water, the earth fermented as new leavened pafte or dough, and fwclled over the fides of the box, part of it falling into the receiver. The fame thing after this happened from every watering and exbaufting, and what is very remarkable, the earth after this felt foft and fatty in the handling ; whereas before it was rough and coarfe to the touch. This propably happened from the difuniting of cer- tain particles in the earth, which while held together made large granules, and gave a coarfenefs to the touch. Another remarkable change in the earth was, that on the eighth day after its being put into the receiver, it appeared to have changed colour, and when held in fome lights appeared grey, and of a mining glofly look. On examining into the caufe of this appearance by the microfcope, the whole fur- face of the earth was feen to be covered with fine (lender filaments like thofe of the fpidei's web. The whole earth ap- peared as it were mouldy, by means of this covering of the threads, fome of which arofe from little eminences on the fur- face, others from other parts, and crofTmg one another they formed a web of fuch fort, that when the earth was watered, the wet would often roll about upon them in large drops for fome time before it broke their texture to get in. This was at firft fufpected to be nitre fhooting out of the earth, but in reality it at length appeared to be a fungous fubftance which vegitated there, and which when once cleared off, never re- newed itfelf again. So long as the fhoots of the feeds in the exhaufted receiver continued to be kept there, there al- ways flood a drop of water upon the top of each, which as it encreafed in fize from time to time, run down the fides of the fhoot and entered into the earth ; but as foon as this was done, there was always another immediately formed on the top of the fhoot.

Though thefe experiments did not fucceed fo far as might have been expected in the growth of the fhoots, yet they prove fufficiently, that neither the elafticity, nor the weight of the air, are neceffary to the germination of feeds, for here were plainly fome feeds which did germinate in vacuo. It muft be allowed that the air however, though not abfolutely an eftential agent, proves an accidental one in this effect, fince a great number of feeds which had not germinated in the exhaufted receiver, did afterwards germinate when the air was admitted to them. The reafon Mr. Homberg gives for the number of feeds mifcarrying, feems a very juft one : he obferves, that there is always a little air contained in every feed, that this expands and di- lates itfelf much more readily in vacuo, where there is no- thing to refirf its motions than in the open air, by which it is prefled on every fide. If therefore a feed be fown in the open air, this excluded air meeting with refiftance from without, can only expand itfelf in a flow and regular manner, fo as to afBft in the explicating the fibres of the included plant ; whereas when the feed is fown in vacuo, the included air burfts out at once with great vio- lence, and ufuaily efcapes without doing its office in ve- getation. If in the violence of its getting out it tears the principal veflels of the young plant, which doubtlefs is often the cafe, then the feeds muft perifh ; but if it efcapes with- out injuring them, then the feeds may germinate without it. Thus it is that fome feeds germinate in the exhaufted receiver. This is the reafon that they germinate but weakly ; and that fo few of the general number do germinate at all. Mem. Acad. Par. 1693. Metallic Germination. Borrichius, in his hiftory of chemi- ftry, gives us fome very remarkable accounts of thefe fort oiger-

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minatims, and of one in particular, for which he quotes a wit- nefs,ashefays, of fo great veracity and fo little credulity, that he ■ might be abfolutely depended on. This perfon he tells us living at Bruflels, was vifited by a ftranger, who entrufted him with a fmall quantity of powder of about the weight of a bailey corn, with which the operation of one of thefe ger- minations was to be performed, and which was afterwards to be returned to him. Three or four pound of river water was to be put into a glafs, and this powder being put into it, the whole was to be fhaken together that fome part of the powder might be diflblved in the water ; after this the water was to be decanted into a clear veflel, and the powder dried. The ftranger came again for his powder, and bidding the perfon who had the water thus impregnated, to put fome ounces of crude mercury into it, he took his leave. The mercury was put in, eight ounces of it, and immediately after there was feen the beginning of the germination. The quick- lilver on all parts fhot out multitudes of filaments, or thread like branches of filver, which by degrees extended them- felves all over the veflel, and even rofe above the furface of the water ; the liquor being poured off, the quickfilver was all found to be converted into pure filver, which flood the fevereft tefts of fire, and was acknowledged filver by the fil- ver-fmiths of the place. Borrichius fe Ortu Chemize. More quickfilver was added to the water, and procured a fecond wood of pure filver, and (a on to the fixth time ; but the liquor grew more languid every time, and at length had no more of this virtue. Stories like this have deluded many people into the facrificing their whole time and fortunes in the fearch of fuch germinations and tranfmutations ; but there is yet no proof of the truth of any thing of this kind ever having been performed. We fee that Borrichius, who is one of the ftrongeft advocates for this opinion among the chemical writers, gives the ftory only at fecond hand ; and had he faid that himfelf had feen it, it would have fcarce been credible without fome further proofs. Phil. Tranf. N i >. 39.

GEROCOMIA, a term ufed by the antients for that fort of medicinal practice, which treated of the proper regimen to be obferved in old age.

GERRES, Gertjli, or Giroli, in ichthyology, names given by the Venetians to a fifh common in that part of the world. It is the Smaris, or Maena alba of authors. Artedi very judi- cioufly makes it a fpecies of the fparus, and diftinguifhes it from the others, by its having a black fpot on each fide, and the pectoral and tail fins red.

GERRHA, r e ^«, among the Greeks, wicker hurdles, re- fembling the Roman vinete, which the foldiers held over their head to fhelter themfelves. Potter^ Tom. 2. p. 93.

GERSA, a word ufed by fome authors for cerufsj or white lead. See Ceruss.

GERYON, a name given by fome of the affected chymical writers to quickfilver.

GESOR, a name ufed by fome of the Arabian writers for gal- banum. See Galbanum, Cycl.

GESTATION, Cycl. the ftate of a woman with child. See Pregnancy.

GESTU c5" fama, an antient writ, where a perfon's good behaviour was impeached, now out of ufe. Lamb. Eiren. Lib. 4. c. 14.

GET-o^T, among bowlers. See Bowling.

GETHYLLIS, in botany, the name of a genus of plants, defcribed by Linnaeus, the characters of which are thefe. The cup is a fpatha of a lanceolated form, compofed of one membranaceous inflated leaf, and containing only one flower. The flower confifts of one petal. Its tube is extremely flendcr and long. The limb is plain, and is divided into fix equal fegments of a lanceolated form, which are of about a third part of the length of the tube. The ftamina are ei- ther twelve or eighteen fetaceous filaments ftanding in the cup. They are fhort and ere£t, and the anthers are oblong. The Germen of the piftil is oblong, and ftands low in the fpatha under the bafe of the flower. The ftyle is capillary, and of the length of the ftamina, and theftigma istrifid and obtufe. The fruit is an oblong, inflated, triangular capfulc, contain- ing three cells in which are numerous feeds. Linnm Gen, plant, p. 206.

GEUM, in botany, the name of a genus of plants, the cha- racters of which are thefe. The flower is of the rofaceous kind, confifting of feveral petals or leaves difpofed in a cir- cular form. From the cup there arifes a two pointed piftil which afterwards becomes an oblong and double headed fruit, bicapfular and filled with very fmall feeds. The fpecies of geum enumerated by Mr. Tournefort are thefe. 1. The larger round leaved geum, called by fome round leaved mountain fanicle. 2. The fmaller round leaved geum. 3. The rounded leaved geum with the piftil of the flower of a pale colour. 4. The rounded and finely cre- nated leaved geum with the piftil of the flower of a fine red. 5. The larger rounded leaved geum with the piftil of the flower red. 6. The fmaller roundifh leaved geum with the piftil of the flower red. 7. The geum with the fmalleff. rounded leaves. 8. The fmaller marfh geum with oblong crenated leaves. 9. The fmall branched Portugueze marfh

geum,