The Encyclopedia britannica; a dictionary of arts, sciences, and general literatureWith new maps, and original American articles by eminent writersWith American revisions and additions, bringing each volume up to date . -Dr Engelmanns scribed below in his own words. The eye end, suitable foe heavyspectroscopes, &c., is fitted to the butt end of the telescope bybayonet joints and tightening screws, so that it can be exchangedfor a micrometvic eye end with almost as little trouble as the cx-jchanging of an eye-piece. The illumination of the circles and themicrometer is by elect
The Encyclopedia britannica; a dictionary of arts, sciences, and general literatureWith new maps, and original American articles by eminent writersWith American revisions and additions, bringing each volume up to date . -Dr Engelmanns scribed below in his own words. The eye end, suitable foe heavyspectroscopes, &c., is fitted to the butt end of the telescope bybayonet joints and tightening screws, so that it can be exchangedfor a micrometvic eye end with almost as little trouble as the cx-jchanging of an eye-piece. The illumination of the circles and themicrometer is by electric incandescent lamps. The instrumentmay be adjusted to any latitude and is probably the most practicaland serviceable equatorial made. The subjoined description of theinew slow motion in declination is taken from Free. M. Dubl. Soc^S1886, p. 107. ?The slow motion arrangements usually used in equatorials are of either oftwo forms, viz.^ (a) an endless screw working into a sector or portion of atoothed circle of long radius, or {b) a screw applying or pushing directly,against an arm, that arm being kept in contact with the scjew by a spiral orsome other form of spring liaving a conBidenible range of motion. The first (a)possesses the disa
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Keywords: ., bookcentury1800, bookdecade1890, bookidencyclopedia, bookyear1892
