fanftr 



Thf Ictttrt- Ftaure represents thfAnraial 

 Idi-i '/// tti'ii 1 1 r ' the Earth round thtSun . //i. 

 fii its Oi-lxt whi,h is an Ellipse., the 



f.rcfittriiit\ ' t'f 'which is about .?. 

 leagues, and on thr first < i 

 The Graduated tifje whirhatasmtiD 

 ilistniice surrvunds theyorthPolein 

 fai-h tiuiiii-ofthcEtii-th .shews the 

 l'iinilli-1 1 'tiniit Kii tain, thif Garde 

 is divided, into ?4 htna-s . 

 The tiqure to the rightmarkt thehour 

 of Sun-rise, that to the left, the hour 

 ot'SwL-set. The point indicates 

 tlie position, of Great Britain with 

 referaux to tfie. Sunatthe varioue 

 hours oftheltoj,- andNight - for 

 EjcampU. it if 2 O ' Clock ji-M.on the 

 first of June, and the horary Circle 

 shews us thatat this time thehour ot 

 Sun -rife if 4 * 3 m and.that of Sun-set 

 7 ^52 T thelfiyht therefore will conti- 

 nue 2* 3"? longer. Ayainonthe first \^j 

 of December the Sunrrises at 7 

 and Sets of the horary Circle indicates 

 at 4^ 4 the time supposed being !. 

 the da)' wiR continue 2 '" 24 longer 

 Atthis period of the Tear the Earth approaches 

 the IVvitfr Solstice when.itsyorthPoleis en 

 veloped in darkness tor twoMonthf will Am-c 

 reached the middle of its long Night . 



Suppose, a movinq bodylR* sub jetted to the int 



oftfo forces One in tlie direction JU, S . the other in the 



dirrflii'ti HI. -I' the intrnsit\- being mdicatftl by the riaht 



lines IR, P. anil HLV the moving body can neither i/n towardf 



S nor JC but must take: an intermediate Course IR. O. with a 



Velocity represented by lIL,-*- It if thus rlrar that the mo\'ing 



body HL. will take the same dirrftian and have the same Velocity 



of Ons force represe/iteJ in Mnanihule by 111. *- at id in direction by 



IIL O M 'o idd hat e imparted to it . The name Residtant or equivalent force 



if on ni t<i thif . When a. (jjrt'e ie described, by llrtuf. of a forrr ihrri-lnl tt' 



a. fixxdpoint S it may be rejiolv edinto two - One in the direction of the Kadjus 



D^S the other i>f the litr\-eV\t^.Thisat:r^eiiitinit tint-e is supposed to ojt only at the 



beiiiniiinuufeiii-h moment white the Motion, isitnit'urm tlir I'rrtor Radius ll)i S. then will 



trust u small truing leU^S A . If this tinre ,-eaxed to art the followi/uf moments the. VeetorEaduu 



would trate a fresh ftiangle rt^nnl tn thr tirst Hut nt the beginning of the next, momattthe ac 



force 11^ k combines with'S^'R and cauftf the moving body to ejchibit the eJfects oftherrsijtant force A HI, 



the sides ofwhirh A/> AB represent thf.fr forces . 



