OF OPTICAL INSTRUMENTS. 123 



ASTRONOMICAL TELESCOPES AND STANDS, 



WITH UNIVERSAL AXIS. 



1394. ASTRONOMICAL TELESCOPE, Si-inch., clear aperture, 4 foot focal length, mounted 



in polished brass, with sliding draw and rack adjustment, star-finder, dew cap, 

 pancratic day-draw, giving powers of 40, 50, 60, and 70 ; 3 astronomical 

 eye-pieces, magnifying to 100, 150, and 200 respectively, with different shades, 

 of glass to sun caps, in stained pine case . . . 25 



1395. ASTRONOMICAL TELESCOPE, 4 feet focal length, 3i-inch. object glass, complete, 



as above . . . . ' . . . 28 



1396. Astronomical Telescope, as above, 4 feet 9-inch, focal length, with 3f -inch., aper- 



ture, four day powers of 45, 55, 65, and 75, four astronomical powers of 

 100, 150, 200, and 250 respectively, and diagonal eye-piece, in case, as above 



35 



1397. ASTRONOMICAL TELESCOPE, 5 foot focal length, and precisely as No. 1394, but with 



4-inch, aperture and 5 astronomical powers, viz., 100, 150, 200, 250, and ,300, 

 in case, complete ...... 45 



1398. ASTRONOMICAL TELESCOPE, with 4^-mch. aperture, and astronomical powers of 



100, 150, 200, 250, and 300 . . . . 58 



EQUATORIAL MOUNTINGS. 



1399. Universal Equatorial Axis, to carry Nos. 1394, 1395, or 1396 telescopes, with 6- 



inch. hour or declination circles, divided on silver, with the latest improved 

 motions, in strong pine case ..... 33 



1400. UNIVERSAL EQUATORIAL Axis, of larger size, to carry Nos. 1397 or 1398 tele- 



scopes in strong pine case ..... 40 



1402. STRONG OUT-DOOR LATH OAK STAND, for axis, No. 1399 or 1400 660 



1403. IRON PILLAR, for ditto . . . . . 7 10 



1404. HIGHER POWERS, added to either of the above telescopes, at 15 to 



150 extra. 



1405. Diagonal Eye-pieces fitted to either of the above telescopes, 1 3s. to 1 10 



1406. FIRST SURFACE KEFLECTION PRISM, for the sun . . 17 6 



1407. TOTAL KEFLECTION PRISM, for the sun . . . . 1 10 



1408. ILLUMINATING APPARATUS . . . . . 2 12 6 



1409. ASTRONOMICAL EYE-PIECES (Huyghenian), Nos. 1 and 2 magnifying to 65 and 85 



15 6 



1410. ASTRONOMICAL EYE-PIECES (Huyghenian), Nos. 3, 4, and 5, magnifying to 125, 



200, and 250 . . . . . . . 110 



1412. ASTRONOMICAL EYE-PIECE (Huyghenian), No. 6, magnifying to 400 160 



1413. Astronomical Eye-piece (Huyghenian), No. 7, magnifying to 600 1 11 6 



1414. ACHROMATIC EYE-PIECES, in which the field is more limited, but applied to 



reflecting telescopes, on the planets their power is very superior, average cost 

 5s. to 15s. dearer than the above. 



1415. ANNULAR MICROMETER, with eye-piece . , 150 



