308 NEGEETTI AND ZAMBKA, HOLBORN VIADUCT, E.G., 



NAUTICAL INSTRUMENTS. 



FIG. 1290. 

 SEXTANTS. 



s. d. 



1589 Reflecting Circle (Troughton's Pattern) 10-inch . . . . 25 

 1290 Ditto ditto, 12-inch (fig. 1290) . . . . 30 



This instrument perfectly corrects the error of the centre by the readings of 

 the three branches of the index ; this property, combined with that of observing 

 both ways, reduces the errors of dividing one-sixth part of their simple value. With 

 this Circle angles may be measured as far as one hundred and fifty degrees. 



1291 Ebony Sextant, 8-inch, best, with Ivory arch 



Achromatic Telescopes, &c., in mahogany case . 6 10 



1292 Metal Sextant, 6-inch (Cadets') Circular pattern, divided 



on Silver reading to ten seconds, three Telescopes, in 



mahogany case (fig. 1292) - . 880 



1293 Metal Sextant, best, 5-inch (Cadets') Triangular pattern, 



divided on Silver, reading to 10 seconds extra power 



to Telescope, strapped horizon adjustments in Box . 990 



1294 Metal Sextant, 8-inch, Edge Bar Pattern, bronzed limb 



divided on Silver, reading to ten seconds, in mahogany 



box 10 10 



1295 Metal Sextant, 8-inch, Oval pattern, bronzed limb 



divided on Silver reading to ten seconds, stump and 



block adjustment and glass reflector to vernier . 11 11 



1296 Metal Sextant, Oval, Triangular, or other patterns, best, 



bright or bronzed limb, Neutral Tint Shades, and 

 extra power for Telescopes, Glass Reflector, &c., in 

 square polished mahogany case with screwed fittings 12 12 



