282 



NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., 



Each. 

 a. d. 

 220 



15 



Each. 

 s. d. 



330 

 110 



1086 Prisms of Glass, of various Density . .110 



1087 Bisulphide of Carbon Prisms 



1088 Spring Stage, for studying the absorption Spectra of 



coloured glasses 12 



1089 Gladstone's Wedge, for exhibiting the absorption spectra 1 12 



1090 9-inch Glass Tube, with Stop-Cock, for examining the 



dark lines seen in gases and vapours .... 12 6 



1091 A Divided Tube, with two compartments and two flasks, connectors, stop-cock 



&c., for exhibiting the increase of dark lines with increased temperature 



and length of vapour 220 



Bunsen's Steatite Burner, with Copper Cone, mounted 



on a stand (M fig. 1081) 12 6 



Spectroscope Forceps (or Pincettes), on an adjusting 



support (N fig. 1081) 11 



Bock Salt Prisms and Lenses, Quartz and Iceland Spar Lenses or Prisms 



1092 



1093 



1094 



supplied to order. 



FIG. 1096. 



FIG. 1095. 



PORTABLE OXY-HYDROGEN GAS POLARISCOPE. 



1095 Complete with Apparatus for producing and Purifying the Gases. Full 

 size Gas Bags and Pressure Boards. Flexible Conducting Tubes. Brass Connec- 

 tions, &c., &c. Best Lime Clock. Mahogany Portable Tripod Stand, as shown in 

 fig. 1095 ... 34 



1096 Ditto ditto with Microscope (fig. 1096) . . 42 



1097 Professor Roscoe's Lectures on Spectrum Analysis (Third Edition), largely 

 Illustrated. Six Lectures on Spectrum Analysis and its Applications, delivered 

 before the Society of Apothecaries. Price 1 Is. 



* See Section Electric Light for Lantern Spectrum Apparatus. 



