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Show VA VA VA The Charaéers are ; F The Leaves grow by Pairs oppofite on the Branches; the Branches are always divided into two Parts, and appear at the Top like an dies, as Sulphur, &c, But Sir Vaac Newton and other Authors, better diftinguith between humid and dry Fumes, calling the latter Ey. halations. Umbrello ; the Flowerconjifts of one Leaf, whick is cut into many Segments, and is fucceeded by one naked Seed, having no Down adhering to it, be thofe watry Particles which are fevered in which it differs from the Valerian. The Species are; 1, VALERIANELLA; é arvenfis, precox, milis, femine compreffo. Mor. Umb. Corn-fallet with a flat Seed. bu= Early low 2. VALERIANELLA3; arvenfis, precox, bu- 3. VALERIANELLA; arvenj/is, ferotina, altior, ‘Taller late Corn- 4. VALERIANELLA; femine ftellato. C. B. P. Corn-fallet with a ftarry Seed. 5. VaALERIANELLA ; cornucopoides, rubra vel Indica. Mor.Umb. Red or Indian Corn-fallet refembling the Cornucopia. The three firft Sorts are found wildin feveral Parts of England. The third is often cultivated in Gardens, for Sallets in the Spring, though either of the three may be cultivated for the fame Purpofe, they being equally good. The Seeds of thefe Plants fhould be fown in Autumn, foon after they are ripe, for if they are keprtill Spring, the Plants feldom come up the fame Summer; the Seeds commonly remaining in the Ground, will come upthe fucceeding Spring, notwithftanding the Place be dug and fowed with other Seeds, as I have often obferved. Thefe Plants will grow in almoft any Soil or Situation, from others by the Motion of the Air, and are carried about in it feveral Ways, accord- milis, foliis ferratis. Tourn, Early low Cornfallec with ferrated Leaves. ; Jemine turgidiore. Mor.Umb. fallet with a turgid Seed. VAPOURS, are defin’d by Naturalifts to and require no farther Care but to keep ’em clear from Weeds, until they are fit for Ufe: They fhould always be cut while they are young, for if they are grown pretty large, they will become ftrong and bitter. The fourth and fifth Sorts are preferved in Botanick Gardens for Variety, but are not of any Ufe. Thefe may be propagated by fowing their Seeds in the Spring, upon a Bed of dry Earth, where they may remain to flower and feed. Thefe are all annual Plants, which muft be fown every Year, or their Seeds permitted to {catter upon the Ground, where they will come up, and thrive without any other Culture, than only to clear *em from Weeds, VAPORIFEROUS, fignifies, caufing or producing Vapours, VAPOUR, is by fome defin’d to be a thin Veficle of Water, or other humid Matter, fill’d or inflated with Air, which being rarefied to a certain Degree by the Action of Heat, afcends to a certain Height in the At- mofphere, whereit is fufpendedtill it returns in form of Rain, Snow, or the like. Some ufe the Term Vapour indifferently for all Fumes emitted either from moift Bo- dics, as Fluids of any Kind; or from dry Bo- ing as the Wind, or Warmnefs of the Air ferves: They rife out of the Sea, Rivers, Lakes, and other Waters. As to their hanging in the Air, we may obferve, in a hot Day, when there is no Wind ftirring, fuch a Company of Vapours to rife out of moift Ground, as make thick Fogs, which are fometimes higher, and fometimes lower, as the Multitude and Motion of the Vapours happen’ to be, They are to be feen as well upon high Grounds as low. Theyare eafily diffipated by the Wind, and particularly if it be a drying Wind. The Sun has the fame Effect upon them; and we commonly fee, when there are thick Fogs about Sun-rifing, they difappear a little after it is up. It is evident, that Fogs do confift of aqueous Particles rarefied, becaufe they mightily bedew every thing that lies open to them. Thefe Particles, being foundly moved, mutt needs fly aloft into the Air ; but if their Motion be fomething faint,: they play about the For this is agreeable Surface of the Earth. to the Laws of Motion, that fuch Things as are about the Globe of the Earth, the more they are moved, the more they recede from the Center of the Earth. Again, thefe Fogs arife out of all Places, mountainous or champain, and continue “till they are difpell’d by Wind or Heat ; but they continue longeft in the loweft Grounds, becaufe thofe Places are fulleft of Moifture, and are not fo muchexpos’d to the Winds: But whereever they be, when the Wind rifes upon them, they are diffipated and driven about, "till we fee no more of them. So, in like Manner, the Heat of the Sun, by putting theminto a brisker Motion, either diffipates them by Rarefaétion, or raifes them y higher, and forms them’into Clouds. _ And whereas fometimes the Fogs ftink, it is not becaufe they come fromftinking Water, but becaufe the Vapours are mix’d with ful- phureous Exhalations, which {mell fo. Perhaps thefe Exhalations would fly up direttly 0 the Clouds, if there were no Fogs to hol them, and fo would nor affect the Senfe ‘ Smelling ; but when they are once entangle and blended with the Fog, they laft as long as hey 3 that does. The Clouds are higher than the Fogs died hang in the Air, and are carried about 19 by the Winds. The Clouds are of an Figures, and fometimes fo thin, that the a of the Sun pafs through them; but at — times they are thick enoughto intercept 4 . obftruét them : They alfo appear © f_feveral aaa VA Colours, as, white, red, and fometimes very dark, The Thicknefs of the Clouds proceeds from the Clofenefs of the vaporous Particles one to another 5 and their Thinnefs from the Diftance of thofe Particles one from another, of which there are feveral Caufes. When they are very thin, they leave fo many Interftices, that the Rays of the Sun dart through themin many Places, but are intercepted in others. Asto the Varieties of the Figures of the Clouds, they arife from their-Plenty of Vapours, and the Influence of the Sun and Wind: For they cannot be varioufly condens’d, rarefied, andcarried about in the Air, but their Figure muft needs be changed, To account for the Clouds hanging in the Air, is a Matter of fome Difficulty, All the watry Particles, of which they confift, are heavier than Air; and fo, if there were nothing to hinder them, they would fall to the Earth. But there’ are two Things that feem to keep them up. 1, The Winds which blow; from all Parts, under the Region of the Clouds, and bear about with them many lighter Sorts of Bodies ; efpecially if thofe Bodies contain but a imall Quantity of folid Matter under a broad Superficies. Andthus it is vifible, how eafy Paper-Kites are kept up by the Wind, when they are mounted pretty high; and fo the Particles of Water, pretty much rarefied, may eafily be fufpended at that Height. 2. New Exhalations and Vapours are perpetually fuming out of the Earth, and by their moving upwards, prevent the Clouds from defcending, unlefs the Denfity of the Clouds over-weigh them. Thus we fee the Vapour of Fire carries lighter Bodies up the Chimney: And Smoke can turn thin Plate of Iron, artfully placed in it, fo ftrongly, as to turn about a Spit and roaft Meat. It is a Queftion among Naturalifts, Whe- ther Clouds and thicker Fogs are compos’d alike ? Or whether there be fomething more in the Clouds? Some think that Clouds are groffer than all Fogs; and that they are compos’d of Flakes of Snow, rather than Particles of Water, fuch as make Fogs. Others fay, it is enough to confider Clouds as a clofer Sort of Fogs. And indeed the Fogs that hang upon the Tops of very high Hills, appear to People in the Plains, to be all one with Clouds; though thofe that are ac ther hinders it. But when the Weath er is calm, and gentle Breezes are felt from the Weft about the Time that the Sun fets ; and from the Zaft about the Rifing of it, it is probable they colle& the Vapours, and precipitate them, by moderately cooling the Air, And_ becaufe the Morning Breezes are more general than the Evening ones, therefore the Evening Dews fall only here and there ; but the Morning ones feldomfail to be univerfal. It is likewife found by Experience, That the Dews are more copious in hotter Coun- tries than in cold ; the Reafonofwhich feems to be this: That the Heat of the Sun does, in the Day-time, raife abundance the Water, which Vapours rarefied by the fame Heat, pers’d far and wide; but of Vapours out of are fo extremely that they are difthe Cool of the Night brings them together again, and con- denfes themto that Degree, that they fall to the Ground, but not in fuch large Drops as Rain does. But in colder Countries, where there are frequent Rains, and the Vapours are lefs rarefied, moft of them come downin Rain, and but a fmall Part turns to Dew. A certain Author fays, That in fome of the hotter Climates, the Earth is without Rain for fix or feven Months together, and is every Summer Seafon fo much parch’d and dry’d, that there is hardly any Moilture to be found in it for three or four Feet deep, and during that Time, the Heats are fo exceffive, that without the refrefhing Dews of the Nights (whichare there very confiderable) the Plants mutt inevitably perith; for there is no Moi{ture they can have, but from the Dews: And yet that Moifture fupports the Trees and Plants in a flourifhing State. Towards the Endof the Day, the Leaves contraét themfelves, by Reafon of the exceffive Heat of the Sun; but by the falling of the Dews at Night, they expandandopen themfelves; fo that in the Morning and Fore-part of the Day they have a moft agreeable Verdure. And alfo this Moifture of the Dews affords fuficient Nourifhment to the Plants to bring the Fruits to Parfection. Dr. Defamiliers has prefented us with the following Attempts, to folve the Phaznomenon of Vapours, Formation of Clouds, and De. fcent of Rain. He tells us, That though this has been a Subject fo often treated of, none of the Ac- them, perceive nothing but a-thick Fog. counts (that he has met with) feem to him There being always many Vapours in the Air, though not always vifible, it comes to to be fufficient to folve all the Circumftances of it. pafs, that great Dews fall even in clear Wea- That as to what Dr. Miewentyt and fome ther, and efpecially in thofe Countries where it feldom rains. Fer when it happens, that others have faid, that Particles of Fire fepa- the fcattered Vapours are colleéted and condenfed together, and forced downwards, they muft needsfall, and bedew Plants and Grafs. The Time for the falling of the Dew is either before the Rifing of the Sun, or after the Setting of it. But in order to its falling regularly, at thofe Times it is neceffary that the Air be calm ; for windy or ftormy Wea- rated from the Sun-Beams, by adhering to Particles of Water, make up Moleculeor {mall Bodies, fpecifically lighter than Air, which therefore by Hydroftatical Laws, mutt rife and form Clouds that remain fufpended, when they are rifen up to fuch an Height, that the Air about themis of the famefpecifick Gravity with themfelves, That 3 |
