Encyclopaedia; or, A dictionary of arts, sciences, and miscellaneous literature; constructed on a plan, by which the different sciences and arts are digested into the form of distinct treatises of . Jifetc^arf^ i :K. Plate CCCIAl. -^^G IiSeon:\f,J/farcf,ce Part I. O Of GlafTcs. the fame fide as the emergent rays, or on the oppofite• fide. Corel. 3. Hence when rays fall :! on bothfules of any Icn?, the focal difiances EF, E/are let It be tlic continuation of the fcmidiametei- Erto the firll focus t of rays fallhg parallel upon thefiirface A ; and the fame rule that ga
Encyclopaedia; or, A dictionary of arts, sciences, and miscellaneous literature; constructed on a plan, by which the different sciences and arts are digested into the form of distinct treatises of . Jifetc^arf^ i :K. Plate CCCIAl. -^^G IiSeon:\f,J/farcf,ce Part I. O Of GlafTcs. the fame fide as the emergent rays, or on the oppofite• fide. Corel. 3. Hence when rays fall :! on bothfules of any Icn?, the focal difiances EF, E/are let It be tlic continuation of the fcmidiametei- Erto the firll focus t of rays fallhg parallel upon thefiirface A ; and the fame rule that gave /-R to rE asR r to EF, gives alfo rR to RE as rt to Ef. WhenceFyand EF are equal, becauie the redtangles under rE,RT and alfo under RE, rl are equal. For rE is tort and alfo RE to RT in the fame given ratio. Carol. 4. Hence in particular in a double-convexor double-concave lens made of glafs, it is as the fumof their femidiameters (or hi a menifcus as their dif-ference) to either of them, fo is double the other, tothe focal diftance of the glafs. F^r the continuationsRT, rt are feverally double their femidiameters : be-caufe in glafs ET is to TR and alfo E/ to ir as3 to 2. Carol. 5. Hence if the femidiameters of the fur-faces o
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Keywords: ., bookcentury1700, bookdecade1790, bookidencyclopaedi, bookyear1798
