The works of Thomas Dick . Brewsters polyzonal lenses, or any oflier largolens, and GK its focal distance ; if a luminousbody CK, as the flame of a lamp, be placed atthe focal point K, the rays of light, divergingfrom CK, after passing Sirough the lens AB,will proceed in a parallel direction^ AE, GH,BP, and may illuminate objects at very consi-derable Stances. AB, fig. 4, represeDtii • tTTILmr OP ELECTRICITY AND GALVANISM. 7S «ect!an ofthe polyzonal lens built of ten differentifiieeei. L, fig. 6 exhibits a fimtt view of the Fig. splitting large stones into shivers. This hasbeen efRoted in
The works of Thomas Dick . Brewsters polyzonal lenses, or any oflier largolens, and GK its focal distance ; if a luminousbody CK, as the flame of a lamp, be placed atthe focal point K, the rays of light, divergingfrom CK, after passing Sirough the lens AB,will proceed in a parallel direction^ AE, GH,BP, and may illuminate objects at very consi-derable Stances. AB, fig. 4, represeDtii • tTTILmr OP ELECTRICITY AND GALVANISM. 7S «ect!an ofthe polyzonal lens built of ten differentifiieeei. L, fig. 6 exhibits a fimtt view of the Fig. splitting large stones into shivers. This hasbeen efRoted in the following manner. SupposeAB to represent a stone or portion of a rock,which is intended to be split into a number ofpieces. Into the midst of this stone a long rodof iron, or conductor CD, is inserted, which ter-minates in a point. When a thunder-<!loud, asEF, passes over the stone, within its striking ISlme lens. ^ Could such lenses be constructedOfthe size of 6, 8, 10 or 12 feet diameter, theyyvould produce a degree of heat from the solarfays far surpassing what has hitherto beeneffected, and be capable of throwing a brilliant<^ht to immense distances. Fig. 6, shows the manner in which a concavemirrar TU reflects the light of a lamp VW,J^laced in its focus, to great distances. It is in^is waj that the light of the Bell Rock, andother light-houses, is reflected to more thanH^itj or for^ miles distant. ? ,1 ? . ^ . , .Fig-6. , T ? ?. ??-. ?•:??/% ..V //I iSk /^ ^ ^ • Mw^^:^— fife^^r^^-—^ .
Size: 1577px × 1584px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., book, bookcentury1800, booksubjectphilosophy, booksubjectreligion
