434 



OPTICAL PROJECTION 



condenser entirely free, or a simple microscope, polariscope, or 

 other attachment can be key-holed on in place of the slide stage. 



For another 63s. the lantern can be supplied with an entirely 

 removable front, and a long solid baseboard can then be fitted 

 with a large projecting microscope, or, indeed, any optical apparatus ; 

 or at another slight extra expense the lantern can be supplied with 

 the bar carrying the lens entirely sunk in the baseboard, thus carry- 

 ing the ' open stage ' idea to perfection. About eighteen months 



FIG. 245. Prof. Jackson's Science Lantern adapted for Opaque Work 



ago I endeavoured to improve this lantern still more by adapting 

 it also for opaque work. This was finally achieved by tilting the 

 whole lantern up from the back so that it threw a powerful 

 beam of light down on to the baseboard. Any opaque object 

 up to about 5 inches square placed thereon, being thus strongly 

 illuminated, can be projected on the screen by means of the usual 

 lens and prism, and the lantern in a moment can be dropped down 

 again and used as just described for either horizontal or vertical 

 work (fig. 245). 



For all-round useful work at a moderate price this lantern is 

 hard to beat. 



