300 NEGRETTI AND ZAMBBA, HOLBOEN VIADUCT, E.G./ 



1198 Geological Compass, for ascertaining the dip or inclination of strata, hills, 



&c., with index, in degrees and inches per yard, in mahogany box, 4| inches 

 square ...;., 10 6 



1199 Ditto ditto, 3 inches 076 



1200 Ditto ditto, 2| inches . 070 



1198io 1200, if with best Bar Needles, 2s. 6d. each extra. 



1201 Geological Compass, Brass mounted, with best Bar 



Needle and leather case (fig. 1201) . .30s. 42s. 2 10 3 10 



FIG. 1202. 



1202 Pocket Alt-Azimuth Instrument, improved by Francis Galton, Esq., F.RS., 

 is a combined Compass and Pendulum or Wheel Clinometer. A most convenient 

 and portable instrument for obtaining, in a ready manner, Angles, Levels,' &c., 

 similar to No. 1170*. The Telescope renders this instrument available for 

 observing, at a considerable distance from the Station, either Magnetic 

 Bearings, Horizontal or Yertical Angles, &c.. &c. 

 Price in case, as fig. 1202 .... 660 



Pocket Alt-Azimuth without Telescope 5 10 



Our woodcut shows the Clinometer side of the instrument, with the Telescope 

 as drawn out for use 



1202* Hydroscope or Telemeter, a simple apparatus constructed by Negretti and 

 Zambra for the Government Ordnance- Department for use in Marine 

 Forts, to estimate the distance of vessels and other objects . 500 



