40 

 OPTICAL INSTRUMENTS, 



SPECTACLES in every variety of Shape and Material, with Best 

 Brazil Pebbles or Glasses. 



OPERA, READING, AND EYE GLASSES. 

 MILITARY, NAVAL, AND ASTRONOMICAL TELESCOPES. 



Oxy-Hydrogen Microscopes, Polariscopes, Achromatic Microscopes 

 CAMERA LUCIDAS. POLARIZING APPARATUS. 



ELECTRO-METALLURGIGAL APPARATUS. 



Single Cell Apparatus; Precipitating Troughs and Batteries; 

 Apparatus for Electro-Plating: Binding Screws; Porous Jars; 

 Plaster Casts; Wax Moulds; and every Material required in the 

 varied Processes. 



Every description of Apparatus for practically pursuing the various 

 Branches of Natural Philosophy, of very superior Workmanship. 



In the Press, and shortly wiil be Published, 



AN ILLUSTRATED CATALOGUE 



OF 



OPTICAL, MATHEMATICAL, CHEMICAL, AND PHILOSO- 

 PHICAL INSTRUMENTS, 



By T. & R. WILLATS, 98, CHEAPSIDE. 



