H Y 



The 



Characters are, 

 flo'wcr has a pcnnancnt empalcmcr.t cf cne te^f^ 

 cut into five fegments which fprcad open. It hath one 

 bell-JJjeped pctcl^ which is divided into five parts^ indented 

 ct their points •, under each cf thcfe fegments is fixed a 

 neSfartum^ which is fitaated about the middle^ and fijut 

 up ler^gthwdys by tn'O lamella. It hath five fiamna 

 tvkfch are longer than the petals terminated by oblong 



furnniits^ and an oval-pointed germen^ ft 



-fhapedfiyk the length of 



by a bifiJ fpreadi 



comes a 



idfe 



ipfuli 



.fi 



This genus of plants is ranged in the firft feftion 

 of Linna^us's fifth clafs, intitled Pentandria Mono- 

 gynia, which includes the plants whofe flowers have 

 five ftamina and one Ilyle. * 



\Ve know but one Species of tliis genus, viz. 



H 



4. There needs only a competent weight of an c^. 

 ternal fluid, to account for ihc riling of water in 

 pumps, fire. 



5. If a bndy be placed under writer, fo :h;it its un- 

 permolt furface lie paraliel to the horizon, the dirc'^ 

 prefllire that it luibins is no more than that of a co- 

 lumn of water, whofe bafe is the horizontrd iunerficies 

 of the body, and its heighth t!ie perpendicuhr dendi 

 of the water. And if the water which leans on 'thr 

 body be contained in pipes which arc open at botli 

 ends, the prepare of the water is to be efti mated 

 by the weight of a pillar of water, the bafe of which 

 is equal to the lower orifice of the pipe, and v/hof» 

 height is equal to a perpendicular, v/hich reaches 

 from thence to the top of the water, althouph the 

 pipe fhould be much inclined any way, or thoiip;h 

 it ftiould be ever fo regularly fliapcd, and much 

 broader in fome other place than the bottom. 



HyDROPHYLLON {Virgint anum) foliis pinnatifidis. Lin, j 6. A body which is immerfed in a fluid, fudains 



Joncq. Hort. Water Leaf with 



pointed leaves. ■ 



This plant grows naturally in many parts of North 

 America, on moifl: fpongy ground. The root 

 of it is compofed of many ftrong flefliy fibres, 



, which fpread v/ide on every fide, from which arife 

 many leaves with foot-flialks five or fix inches long, 

 which are jagged into three, five, or feven lobes, 

 almoft to the midrib ; thefe are indented on their 

 edges, and have feveral veins running from the mid- 



^ rib to the fides j they are of a lucid green, and in the 

 \' fprihg have water ftanding on the cavities, from 



'. whence I fuppofe Morinus gave it the title of Water 

 Leaf, and not from the plant growing in water, as 

 Tournefort conjectures. ■ The flowers rife with foo.t- 



. ftalks from the root, having one or two fmall leaves 

 of the fame ftiape with the lower 5 the flowers are 

 produced in loofe clun:ers hangmg downward -, they 

 are of a dirty white'and bell-fl^ape3, fo make no 

 reat figure. They appear' in June,^ and the feeds 



ometimes ripen here'io Augufl:.^ -r;"^ V-v-v ^f^ 

 _^his plant is very Iiard'y in refpe£f to cold, but it 

 'fhould be planted in a moifl: ricH foil ; for if it is 

 ^planted in a dry warm foil, it'vfiU riot live, unlefs it 

 ^ IS conftantly watered in dry w«?a(ither:. It may be pro- 

 'Saeatcd by parting of the ro6ts,"wKich fliould be done 

 /in autumn, that the plants may be well rooted be- 

 fore Iprihg, fofotherwife" tliey^wHr require a g^^ 

 " deal of waten"^ It requires a n;iOifl foil ^nd Ihady 





*'»4 - 



fituation. 



,-i 



HYDROPIPER, the common biting' Arfe-fmart, 

 which grows in great plenty m moifl: places near 

 ditches fides almoft every where. 





HYPRPSTATICS [vipcfcUn, of CXp; water, 



and foUfiKVij of fccro;, ftanding, of iVr/xt, Iftand or flop ^ 



. Hydroftatics being conceived as the dotftrine of the 



'^'quillibrum' of' liquors,] or the doftrine of the^'gra- 



, vitation of fluid j'or it is that part of the cnechanics 



which confiders the weight of gravkyoffluid^ bodices-, 



particularly of water, and of folid bodies Tm'merged 



tnerein. ■,, ^ - ='^-3 'ivrnV •-'*'c. '■' "^^'-'^v.;? -i^^fn'fitQ.dih 

 ''To Hydroftatics Dclongs whatever relafe3^''t6 the 



' gravitip^ and ^equilibria of liquors, with the art of 



weicrhincr bodies ia.!.water, in order to eftimate their 



fpecific gravities.;- ^iHr^^, ^i-IXv :V..,: .; j^-V; 

 jQi the ufe of this fcience jn horticulture, tfie Rev. 



Dr. Hales* in his excellent Treatife of Veo;etable Sta- 

 . ticks, Jias^ given many examples,, by experiments, 



fhev/ing the quantities of moifturc imbibed ancf per- 



fpired by plants and trees, neceftary to be known, in 

 . ^orderto promote the bufinefs of vegetation. ; 



Some of the moftufeful heads of this fcience 

 ^t. That the upper parts of all fluids prefs upon the 



Mower. />-' '■ - -. ,..--.' , / ^".:,^''r ■■ 



* V 





t^ ^ 



* 



^ 



^ iV.Jhat a lighter fluid may gravitate or prefs upon 1 

 heavier. . . — v - . 



, 3. That if a body that is contiguous to the water, 

 be altogether, 'or in part, lower than the upper fur- 

 face of the vvater*^ the lower part of Hie DO 

 be prelled up,ward« by the water which touches it 



P 



beneath. 



"^ K*: •%■ -^a ■ Hr ^^ 



-f. 



'-I 





\.. 



V 



natural prefiiire from the fluid, which alfo increaft 

 • as the body is placed deeper beneath the furface of 

 the fluid. 



7. Thereafon why water afcends in fiphons, and 

 by which it flows through tliem, may be explained 

 from the external prelfure of fome other fluid, with- 

 out having recourfe to the abhorrence of a vacuum. 



8. The.moft folid body, which will fink by its own 

 weight at the furface, yet if it be placed at a depth 

 twenty times greater than that of its own thickncfs 

 it will not finic, if its defcent be not aflifted by the 

 incumbent water. 



- • * /" 



9. If a body which is fpecifically lighter than a fluid, 



be immerfed in that fluid, it will rife with a force 



proportionable to the excefs of gravity in that fluid. 



10.^. If a body which is heavier than a fluid be im- 



: merfed, it will fink with a force that is proportiona- 



; '. ble to the excefs of its gravity. ' ■ '■ ' ■ ' ^ -. 



I - i'l. If any veflel be filled with water, or any otlicr 



! . liquor, the furface of which is capable of being even, 



it will continue fo till difturbed by fome other extcr- 



: nal caufe. ' ■ ^ ^ . - • - • " 





''-'Iri* 



- - iaV When the fluids are prefixed, they are prefled 



on all lides. '-- ' '"^- . 



uaque, 1. e. 



*•*. ^ ^,^ **_'•, 



t'^ 



\ How far the knowledge of any of thefe prbpefttes 

 - of fluids may conduce to the philofophical improve- 

 ment of gardening,"'and the bufinefs of vegetation, 

 ! will be more clearly" perceived when well confidered 

 ■ by the ino-enious aitift, than being fet forth by wdrd^ 

 HYGROMETER ^ly^UPico,, of Cy^k, moift, and 

 I '[Air^ov^ meafure, of p7fiw, to meafure,] is a machine 

 ' or inftrurhent contrived to fliew or meafure, the 

 mpiftnefs and drinefs of the air, according a's it 

 ; abounds v/ith .moift or dry vapours, and to hicafure 

 and eftimate the quantity of fuch moiftnefs and 

 f drinefs.' 



V* . I 



,1 Jt^ir 





\ There are divers kinds of Hygrometers; forwhat- 

 : ever body either fwells or flirinks by drinefs or moi- 

 ; _fture, is capable of being 'formed into an Hygrome- 

 ; ter ; fuch are the woods of moft kinds, particularly 

 ' Afli, Deal, Poplar,- &c. fuch alfo is a cord, cat- 



; gut, &d. 



' V - **■ ^ 



t- fc .= « 





i ;Sj:retch ^hempen cord or fiddle-ftring along a' wall, 

 ^bringing it oyer a truckle or puUy ; and to the other 

 ; end tie a weight, unto which fit a ftyle orfncJex; 

 . ,on the fame wall fit a plate of rhetal, divided into 

 i anj^ number of equal parts, "and the Hygrometer is 

 » complete. ■t;r;- rrzrr ^-ntr rr*^: ':fT. z:r.ii t^:};-- • - 

 V For it is a matter , of undoubted obfervation, that 

 i moifture fenfibly fliortens the length of cords and 

 : ftrings ; and that as the moifture evaporates^ they re- 

 ; turn'totheif former length, and the like may befaid 

 " of a fiddle-ftrins;. ff- nf'j) 





The weight therefore, in the prefent cafe, upon an 

 increale of the' nioifture of the air, will afcend, and 

 . upon a' diminution of the fame will defcend:^' 

 '. Hence, is the index ??vill fliew the fpaces of afcent and 

 '' defcent, and thofe fpaces are equal to the increments 

 ■ and decrements of the len2;th of the cord or ^ut, u^^ 



^ ( -»- - ' 



inftrument will difcover whether the air be more or 



; lefs humid now, than it was at' another given time 



The 



