GLOBE. 



wiH bo equal ta the elevation of the pole, or latitude of the 

 places required. 



Any hour of the day or night being given, to Jliczu all thofe 

 places to which the fun r'lj'es and fets ; luhere it is noon or viid- 



'light ; and where d'ly or night 1. Find wliat place tiic fun 



is at that time vertical to, as already taught. 2. Let this 

 place be brought to the zenitli of the wooden liorizon, 

 :. e. elevate the pole as the latitude of that place requires ; 

 then will tlie places on the eaftern iide of the horizon be 

 tliofe the fun is fettiiig to ; and on the weftern fide, thofe 

 he rifes to : thofe under the upper feir.i-circle of the meridian 

 Ir.ive it noon ; and tliofe under the lower, midnight. Laftlj-, 

 to thole of tiie upper hemifphere it is day ; and to thofe in 

 the lower, night. 



Hence, as in the middle of an ecli])fe, the moon is in tliat 

 degree of the cch;)t!c oppofite to the fun's place ; by the 

 prelent jjrobleni it may be (liewn what places of the earth 

 then fee the middle of the eclipfe, and wliat the beginning 

 or end in 2;. 



To Jind luhat places of the earth a planet, e. gr. the moon, is 

 •vertical to any diij of the year. — I. Mark the planet's place 

 on the globe, as abuve taught. 2. Bring this place to tlie 

 meridian, and note the degree over it. 3. Turn the globe 

 round, and the places which pafs under the point are thofe 

 required. 



The declination of a Jlar, or any other phenomenon, given, to 

 find -what parts of the earth the fame is vertical to. — Count as 

 many degrees in the meridian, from the equator towards 

 one pole, as are equiil to the given declination ; viz. towards 

 the north, if the declination be to the northward ; and 

 towards the fouth, if the declination be fouth. Then turn- 

 ing it round, the places that pafs through the extremity of 

 this arch in the meridian are the places required. 



'To d. terniine the place of the earth where any Jlar, or other 

 telejlial phenomenon, will be vertical at a given hour 1. Ele- 

 vate the pole "acc(«'ding to the latitude of the place, from 

 v/hofe noon or midnight the hours are numbered. 2. Bring 

 the fun's place for that day to the meridian, and fet the 

 index at twelve o'clock. 3. Determine the place of the 

 ftar on the furface of the globe, and bring it to the meri- 

 dian ; the index will fliew the difference of time between the 

 impulfe of the fun and ilar to the meridian of the place : 

 note the point of the meridian over the place of the liar. 

 4 Find in what places of the earth it is then noon, and let 

 tlie index to twelve o'clock. 5. Turn the globe towards 

 the well, till the index has palled over the interval of time 

 between the culmination of the fun and liar. Then, under 

 the point of the meridian, before oblerved, will the place 

 required be found. And hence may always be found what 

 place a liar, or other phenomenon, riles or lets to at any given 

 time. 



To place the globe in fuch manner, under any given latitude, 

 as that the fun Jhall illuminate all thofe regions ivhich hi afnially 

 illumines on earth. — I. Ileftify the globe, i.e. elevate the 

 pole according to the latitude of the places bring the place 

 to the meridian, and fet the globe north and fouth by the 

 compalTes ; thus, the globe having the fame fitualion «ith 

 regard to the fun as tlie earth has, that part ihereoi will be 

 illuminated which is illuminated on earth. Ilence alio the 

 globe being lituate in the fame manner, \\l,en the momi 

 Ihines, it will (hew what parts are then ilhiminaled by the 

 Jiioon. 



And in the like maimer, we may find when the fun and 

 jnoon rife and fet at any given time. 



To find the dijlaiue of two places on the gl'be. — Take the 

 ^iven places in the conipalTes, and apply tl.eni to the equa- 



tor : the degrees wliidi there fuLtcnd being reduced into 

 miles, leagues, or the like, give the diflances required. 



rile fame may be done, and that more comniodioufly, by 

 laying the graduated edge of the quadrant of altitude over 

 the two places, and noting the degree intercepted. 



Jo ^nd how any one place bears from another. — Bring One 

 place to the meridian, and lay the quadrant of ahitudc 

 over the other, and it will fliew on the horizon the point of the 

 corapafs on which the hitter bears from the former. 



Problems on the terreftrial globe may fometimes be ad- 

 vantageoufly iolved, by conlidering the liuri-zon as the circle 

 of illumination, and bringing the fun's place to llie zenith. 



To find for any given day and hour thofe places where the fun 

 is then rifing or felting; thofe places where it is noon, and in par- 

 ticular that place wh re the fun is vertical ; thofe places thatha^e 

 morning or cv.ning twilight ; and thofe places where it •aas 

 midnight. — Find the fun's place in the echj>tic for the given 

 day, bring it to the brazen meridian, and mark its declina- 

 tion. 



Klevate the (north or fouth) pole as many degrees abo\c 

 the horizon as arc equal to the fun's declination (north or 

 fouth). Bring the given place to the meridian, and fet tho 

 index to the given hour, then turn the globe on its axis, till 

 the index comes to the upper twelve, and fix the globe in 

 that portion. All theie places along the wcllern edge of 

 the horizon have the fun riling, thofe along the callerii edge 

 have the fun fetting : it is noon to the places under the 

 brazen meridian, and amongll thein the iun is vertical to 

 that place, which Hands under the degree of the lun's decli- 

 tion. 



Thofe places that are within iS of the weftern femi- 

 circle of the horizon have ii;orning twilight, and thofe 

 within 18 of the ealhrn femi-circle have evening twilight : 

 and it is midnight at a'l thofe places under that part of the 

 brazen meridian which is below the horizon. In fliort, it 

 is day to all places aViove the horizon, and either twilight 

 or dark night to all thofe which arc below it. 



The dav and hsur of a lunar eclipfe being giv n, lo f,nd ikofe 

 pfnceT where i! wil! bt vifiLlc. — Find the place where the fun 

 will he vertical when the eclipfe begins, and rettify the 

 globe, in refped to latitude, for the antipodes of that place. 

 Then bring the antipodes to the upper part of the brazen 

 meridian, and fix the globe in that pofition, and the begin- 

 ning of the eclipfe will be vifible to all places which- are 

 then above the horizon. 



To find the proportion which the' land bean to tie fea. — For 

 this purpofe Dr. Long propofcs to take the papers of a 

 l.irge terreilriij globe, and after f^parating the land from 

 the fea with a pair of fiiil"ar>, to weigli them carefully ia 

 fealcs. This method fuppofes the globe to be cx.-.c-ly de- 

 lineated, and all the papers of equal thickr.efs. By an cx- 

 perif.ent on the papers of Mr. Senex's lewntecn inch glob?,- 

 he found that thofe comprehending the fen woi^heJ 549 

 grains, and the otliers only 124; whence he iniers, thai 

 almoll tliree-fourth parts of the furface of our earth between 

 the polar circles are covered with water, and that littlr 

 more than one-fourth is dry land. Dr. Long omitted 

 weighing the papers witliin the polar circles, becaule the 

 proportion which the land bears to the fea within them 1'?; 

 not afcertained. Long's Allron. vol. i. p. J 68. See Mag 

 niiiidc of the Earth. 



Gl.on.'^, To conlh-u.1 a dial by the. See Dial. 



The celellinl globu has been improved by Mr. Fergiifon : 



in this globe, (P/j/fX\'. .dfironorr.y,Jig.lZ2.) anarchMKH, 



of I'^h', is fixed on the north pole of the axis, above the 



hour circle ; and at the end is fixed an ttprijjht pin HG, 



7., r 7. Aaudin^ 



