M \r 



tiw .qHar of UM iflwrv opposite 

 b Katod. II UM lobe wrre tra* 

 rt wold lbe> H UM opposite com 

 I'.mtranr lo Ike arUwffrap'iir. thu meU 

 Uw CMU of UM MMp. an.l enlar|Cs <* 



of UM syfcsn opposite Ute < 



It the (lobe wrre transparent, the 

 ' nuicate nurfiuf. 

 turlhod contract* 



I of UM BMiCaBd Jnt i> toward* the 

 M. OwMwrto UM *a|ual arm of the 

 and the difficulty at Qndiog the tree 

 UliMdv ud kwgilod* of places. tht projection i- 

 4 rarh eMployed. (3) In order to rectify the 

 affaMM effscU of UM two preceding. UM globular 

 pc..,~tio. a unification of UM two, is generally 

 tlBjilsiL If we Mpposs UM eye to be removed 

 frwn UM Mrface to dislsane equal to UM nine of 

 AT of UM cirrvaMrribiag circle, the projection i- 

 nUM (lotmUr. In other words, if the diameter of 

 UM sphere be 900 part*, it must be product- . 

 UMS* part* in onUr to ^ive the puint of projection. 

 AD Mrirliain and parallel* in tliU projection are 

 ia raaliljr elliplinU rutvr. ; Imt a tlwy |.i.nrli M> 

 Meariy to cirralar am, they are very rarely xliown 



The ooMtractioa of UM (lobular or e<|ui<lUtant 

 rojerlMI i a* follow* (fig. I ) : Dewril* a rirrle. 

 mrawat a meridian. an<l .Iraw two 

 fcMMton. NC8 aad WCE. perpendicular to each 



r. UM MM for a central meridian, the otli<>r for 

 UM lMtor. Then N and S will rvprewnt the 

 rtorth awl MmUi polo. l>n !! i*arli of the quiul- 

 ranu into nin equal _paru, and earh of the radii, 

 <l-i int. i nine equal partM. 

 - i.tli way*. anl tin.l on it t lie centre* of 

 which will paw through the three point* 



Mloii U.tli 

 latitn.lv. 



prodoced the n-nin-* 



of circle* which mat paw thnni^li . b, &c.,and tin- 

 polem. Hariax el>rtd UM lirt meridian, numWr 

 UM Hfcifi Meendvely to UM eart and wwt of il. 



70,o:e..aad thweamdoKrilM 

 Mm el UM^mator will be UM parallel* of 

 In like mtmum, fad OB \VE prodoced th 



The impowbilitr 



of >pecial parti 



gvtUtue a wtiabetory repre 

 arti of the t>here liy anv of 

 BMlhodi Irwl- to the drain* for olheni 



>f all 



whow urfaon 



can he aocoralely developed or rolled out upon a 

 plan* without alteration, UM eone and ,-v lin.b-r ap 

 the character of the '.(.here. A 

 i <> parallel* not far 



_.jspn<U very nearly to 



Uk conical sooe ; whence it i. ii,.,i eoaioa] d.- 

 nu make the hast projection* for lin.it.-.! 

 of UM earth's surface, and even with *.,< 



prnjeetioa of Karope (fig. 2) U , ..,, 

 * tlraw a IM- In..- A II . l.iiuvt it in I . 

 and al that point erert a i-n.n.licular. Kl>. to form 



'. 



f'MiniTto he hero 

 '' the parallel, of 4F a 



and 



J IneMllsjile, in proportion to tl.- degrees 

 of UUtwfe in lhn parallel., and if trait:lit lin- 

 " ;** UmMgfc I|MM> pnmt. from C t|. 



1raibt 1 

 >risjt~ th. weVidUa. fw eVr . v ":. " " ' \ 



Uoa o tfc, cn.ic pr,. .,,l.|.. (,., .. 



. uch a* of A.ia. 

 ,arallel of lalilu.b- 

 J proportional distance*, whirl, 

 rvia* of UM BMridian line* ontwanl 



I. all UM sMJeetCT hitherto described the 



iion citlii-r of thr north and south, or of tin- 

 and <T>t, i> represented by a curved line, so 





Kg. 2. Conical Projection of Europe, 



that on Huch a map the course of a vessel \\onlil 

 alniORt alwayH be laid down in a curve, \vliicli cmilil 

 only l>o described by contimuilly laying oil' from 

 tln> in.-ii.liaii a line at mi an^le equal to tliat made 

 with the tm'riuian by tbe point of the coin] 

 which the ship wag sailing. If tin- M-S-C! wi 

 fi.H-r ill a direct north-east couix- by one of the 

 pirM.iii- |.ioj.-.-tioiis. -lir \\onlil. if hind did not 

 int. -r\ 'lie, ileacribe a spiral. Tlie mariner, how- 

 V.T. requires a chart which will enable him t<> si. -IT 

 h|K course by miiipaKf in straight lines only. Tbi- 

 valuable instrument is Mi]i|>licd by Mercator's 

 chart, a c\ limliical |iroji'ction in which all the 

 meridians arc siiai^ht lines perpendicular t.i tin- 

 equator, ami all the jmnillels struichl lines jmrnlli-l 

 to the equator. It IB couutructed thus (fig. 3) : A 



Kf. 3. Merostor'i Projection. 



line, AB, is drawn of the required length for tbe 

 equator. Thin line is divided into 36, 24, or I v 

 |>arti, for meridians at 10", lf>, or 20" apni 

 the meridians an- then drawn through thew pcipeii 

 dicnlar to Alt. From a table of meridional parts 

 (a table of the numlier <if mintites of a .1. 

 lonijitiide at the equator comprised iH-tneeti that 

 mid .-\ery parallel of latitude up to 89) take the 

 the parallels, tropics, and arctic circles 

 fr.im the equator, and mark them oil to north and 

 muth of it Join these point s, and the projection 

 made. 



