R A 



R A 



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At Townly in Lancalhire, obferved by Mr. Townly 



Proportion of Rain falling yearly, and its proportion in fevcral places. 



Upminfter in Effex, by Mr. Derham 

 Zurich in Switzerland, by Dr. Sceutcher 

 Pifa in Italy, by Dr. Mich. Angl. Tilli 

 Paris in France, by M. de la Hire 

 Lifle in Flanders, by M. de Vaubin 



42 



'9 



32 



43 



19 



24 



Inches 



T 



f 



T 



Proportions of the Rain of feveral years to one another. 



At Upminster 



1700 

 1 701 

 1702 



1703 

 1704 



19 Inches 03 Cent 



18 

 20 



23 



15 

 16 



69 



38 



99 

 81 



93 





At Paris. 



21 Inches 38 Cent, 

 27 



»5 



18 



21 



14 



78 



42 



20 

 82 



*^ 



Proportion of the Rain of the feveral feafons to one another 



dfa ' ' 



1708 



Depth at 

 Pifa. 



*" I 



Inch. 



January 



February 



March 



April 



May 



June . 



Depth at 



Upminfter 

 Inch. 



Depth at 

 Zurich. 



Half year 



6 



41 



2 



28 



3 



28 







46 



2 



65 



2 



03 



I 



25 







96 



3 



33 



2 



02 



4 



90 



2 



32 



28 



82 



16 



67 



r 



\ 



Incl 



1. 



I 



64. 



I 



- 



65 



T 



I 



51 



4 



69 



I 



91 



5 



r 



91 



r 



'7 



3 1 



1708 



July 



Auguft 



September 



Oftober 



November 



December 



Half year 



Depth at 

 Pifa. 



Inch. 



Depth at 

 Upminfter 



o 00 



2 



7 



5 

 o 



o 



27 

 21 



33 



13 



00 



.14. 94 



Inch. 



o 



o 



II 



II 



94 

 46 



23 

 86 



97 



Depth at 

 Zurich. 



8 57 



Inch, 



3 50 

 3 15 



3 - 02 



2 24 



o 62 

 2 62 



15 35 



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The Reverend Dr. HalSs; in his excellent Tredtife of 

 Vegetkble Staticksr tells Us, that thb quantity of 

 Rain arid dew that falls in a_ year is, at a medium, 

 i2 inches, and that the quantity of the earth's eva- 

 poration in a year isat leaft 9 + 4 inches, firice that 

 is the rate arwluch it evaporates in a fummer*s day, 

 from which 9 + 4- Inches is, to be deduced 3. 39 

 inches, for circulating daily dew, there remains .6. 2 

 ' in6h*es7 ^vhich 6. 2 inches deduced from the quan- 

 ^tity of Rain which falls in a year, there remains at 

 Icaft 16 inches depth to replenifti the earth with 

 moiftiire for vegetation, and to fupply fprings and 





rm'^ 



Anton, de Dornifiis firll'accounted for the Rainbow in 

 ^61 ty he explained at large how it was formed by re- 



fradlion and reflexion of the fu n- beams in fpherical 

 ' drops of water; and confirmed his explication by ex- 

 ^penments made with glafs globes, &c. full of water, 

 -wherein he was followed by Des Cartes, who mended 



and iffiprbved upon hiradcount. ' '' ' "" " ' 





' . 



rivers. 



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— * 



'-' Hence we find that 22 inches depth of Rain in a 

 ^-yearTs fufficient for all the purpofes of nature in fuch 

 *-• flat rotih'tries as is that about Teddington near Hamp- 

 '' ton-Court ; but in the hill countries, as in Lancafhire, 

 f tliere Tails 42 inches depth of Ram water, from 



'- ^"wliich d'eSuftihgTeven Thches for evaporatrbn, thfere 



-remains 35 Tnches depth of^water, befides great fdp- 



jf)lies from miicli more plentiful dews than fall in plain 



A A -- * 



But as they were both in the dark as to the true ori- 

 gin of colours, their explications are defeftive, and 

 infome things erroneous, which, it it is one of the 



glories of the Newtonian dodrine of colours, to fup- 

 ply and correct. ; - - 



The following properties are afcribed to the Rain- 

 bow: 



-'-* . 



-> 





countries. 



* > V '. X 



'>- 



i»- 



s - 



W'. 





*r- --- -. 



'* - _. 



' >^ W vaft ftores feemfo abundantly fufficient to an- 

 V -'"^^fwer the great quantity of water wKich is conveyed 

 :':>::::^^away by fprings and rivers from thofe hills, that we 

 ;%: : .need not have re^ourfe for lupplies to tKe great a!)yfs, 

 .; , ' wlhofe furface at high water Is furmbunted fome huri- 

 J"^.'dreds of feet by ordinary hills, and fome thoufands 



of feet by thofe vaft hills, from \yhence the longeft 



v^ and greateft rivers take their rife. ^'^ 



' R A I N B O W, a meteor in form of a particoloured 



'-arch or femicircle, exhibited in a rainy iky oppofite 



the fun, by'the rarefaction of his rays in the drops 



\- of falling rain. :''.-' T '' :^->? \ "'/v r^' : 

 : ;The Rainbow, Sir Ifaac Newton obferves, never ap- 

 pears but where it rains in the funlhine, and may 

 be reprefented artificially by contriving water to fall 

 in Iitde drops like rain, through which the fun fhining 

 exhibits a bo'w to the fpe£lator's eye placed between 

 the fun and the drops,' efpecially if a dark body, e. g. 

 a black cloth be difpofed beyond the drops.' ' 



I. That it never appears but in a place oppofite the 

 fun; fothat, when we look direftly at it, the fun is 



r always behind us. •'<■■ ;;:"*•%.,. -• r '^ 



^^2- That when the Rainbow appears, it always rains 

 ^ t 'lomewhere. -■^''^■.- --}-^ 0-i>^;^t.:tO'^-:;::' ;- ', 



-^''3. That the conftant order oFtBe colours is, thatthe 



; >''OUtnh6ft is red* or Saffron colour YtTien'extIf yellow; 



I' "the third is green -, the fourth or inmoft is Violet or 

 ' blue ; but thefe colours are not equally bright. 

 '4. Two Rainbows appear together, one of which is 

 ' higher and larger than the other, and fhews the afore- 



• -, faid colours, but in an inverted order. ■'^-*-*'^V'" ^ 



5. The Rainbow is alv/ays exaftly round, but does 

 r not always appear equally entire, the upper or lower 



parts being very often wanting. 



6. Its apparent breadth is always the fame. . 



7. That thofe, who ftand upon plain low ground, 

 ■^ never fee above half its circle, and oftentimes not fo ■ 

 /much. ■'"' 



^ .^ -; - 





a"-f e 



- ■ 



8. The higher the fun is above the horizon, the lefs 



of the circle is feen, and, if there be no cloud to 



hinder, the lower, the more of it. 



g. That never any Rainbow appears, when the fun is 



above 41 degrees 46 minutes high. ' 



Lunar (Rainbow :) The moon alfo fometimes exhibit^ 



the phsenomena of an iris or bow by the refradlion of 



Tier rafs m'the drops of rain in the night tihie. 



.: -^:':>.- . Ariflotle 



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