The British Encyclopedia, Or Dictionary of Arts and Sciences: Comprising an Accurate and Popular View of the Present Improved State of Human Knowledge : Illustrated with Upwards of 150 Elegant Engravings. N - R. 5Longman, 1809 - 680 pages |
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Page 37
... lens that collects the rays of light issuing from the objects , and throws ... convex ones . Contemporary with Maurolycus was John Baptista Porta , of ... convex or concave glasses ; and he seems even to have made some small advances to ...
... lens that collects the rays of light issuing from the objects , and throws ... convex ones . Contemporary with Maurolycus was John Baptista Porta , of ... convex or concave glasses ; and he seems even to have made some small advances to ...
Page 37
... converging rays meet , is called the focus . The point towards which they tend , but ... convex , has one side flat , and the other convex , as △ ( fig . 3. ) A ... lens , as FG , is called its axis . Of Refraction . If the rays of light ...
... converging rays meet , is called the focus . The point towards which they tend , but ... convex , has one side flat , and the other convex , as △ ( fig . 3. ) A ... lens , as FG , is called its axis . Of Refraction . If the rays of light ...
Page 37
... lens is a portion . When parallel rays , as A B ( fig . 5 ) fall upon a double convex lens , they will be re- fracted , so as to meet in a focus , whose dis- tance is equal to the radius or semi- diameter of the sphere of the lens . Ex ...
... lens is a portion . When parallel rays , as A B ( fig . 5 ) fall upon a double convex lens , they will be re- fracted , so as to meet in a focus , whose dis- tance is equal to the radius or semi- diameter of the sphere of the lens . Ex ...
Page 37
... convex lens , they are collected at a point nearer to the lens than the focus of pa- rallel rays . If they diverge before they enter the lens , they are then collected in a point beyond the focus of parallel rays ; unless they proceed ...
... convex lens , they are collected at a point nearer to the lens than the focus of pa- rallel rays . If they diverge before they enter the lens , they are then collected in a point beyond the focus of parallel rays ; unless they proceed ...
Page 37
... convex lens , at the distance of twice its focal length from the hole ; at the same dis- tance behind the lens , where they are col- lected by its refraction , they are received on a second prism , whose refracting angle is equal to ...
... convex lens , at the distance of twice its focal length from the hole ; at the same dis- tance behind the lens , where they are col- lected by its refraction , they are received on a second prism , whose refracting angle is equal to ...
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acid action ammonia angle angle of incidence animal appear axis benevolence body botany called calyx centre chyle circle class and order colour common compound connected consequently consists convex convex lens corolla degree distance distilled drupe Dubl earth ecliptic Edin effect employed equal Essential character feelings feet fixed flowers fluid fossil genus glass heat Hence ideas inches instrument iron ject Jussieu kind length less light Lond manner matter means ment metal mind Monogynia class motion mucilage muriatic muriatic acid Natural order nitre nitric acid object observed organs oxide oxygen parabola parallel pass perpendicular person piece plane plants Plate pleasures potash pound principle produced proportion quantity racter rays receiver refraction seeds sensation sensible side solution sometimes species specific gravity stances substances sulphur supposed surface term tincture tion Triandria tube vegetable vessels volatile oils weight