I. MICROSCOPES. 909 



microscope. Messrs. 11. Field & Co., of Birmingham (makers of the Society 

 of Arts prize microscopes), have undertaken to make and keep it for sale to 

 the public, and to supply with each instrument a copy of the paper on " The 

 Simple Microscope as an Educational Instrument," by W. Teasdale. 



3557. Microscope Stand with Chain Movements, exhi- 

 bited in 1851. William Ladd $ Co. 



Educational Microscope. Plain stage, with dividing 

 English object glass 2-inch, t-inch, J-inch. In cabinet. 



Edmund Wheeler. 



Educational Microscope, with mechanical stage, with 1- 



inch 15, and J-inch 70, English objectives; in cabinet. 



Edmund Wheeler. 



Dissecting Microscope, 3 powers. 



Edmund Wheeler* 



Dissecting Microscope, with glass stage and mirror, 

 3 powers. Edmund Wheeler. 



Focket Microscope, for collecting diatomaceaa, &c. 



Edmund Wheeler. 



Pocket Microscopes, for botany, entomology, &c. 



Edmund WJieeler. 



3557a. Polarising Microscope, large Des Cloiseaux pattern, 

 capable of being placed either horizontally or vertically by means 

 of a joint and clamp, with all requisite accessories for the complete 

 study of the optical bi-refracting properties of natural or artificial 

 crystals, such as a goniometer for measuring the distance between 

 optical axes in air or in oil, at various temperatures ; ice-pan for 

 oil ; copper stove with thermometers and spirit lamps ; the micro- 

 scope frame and Nicol polarising prism, both being movable by 

 means of a rack and pinion. M. A. Picort, Paris. 



3557b. Polarising Microscope, large pattern, with all 

 requisite accessories, the body of the microscope alone being 

 movable on the stand. M. A. Picort, Paris. 



3557c. Polarising Microscope, small pattern, mounted 

 vertically with a small goniometer for measuring the distance 

 between axes in air. M. A. Picort, Paris. 



366O. Microscope Stand, medium size (No. Ib in the ex- 

 hibitor's catalogue), with rack and pinion for the coarse adjust- 

 ment, and with rotation round a vertical as well as horizontal axis, 

 with five eyepieces, and Abbe's illuminating apparatus. 



C. Zeiss, Jena, 





