XI. INSTRUCTION. 



975 



Pantographe of transmission. 



8. Diagrams of 



(#.) Shadow and penumbra. 



(&.) Lateral inversion of reflected image. 



(tf.) Distance of image behind mirror. 



(d.) Refraction by prism. 



(e.) convex lens and formation of image. 



(/.) concave 



(<?.) The human eye. 



The foregoing set is contained in a strong case, 

 24 x 18 x 9 inches, with fittings for facilitating 

 the employment of the apparatus. 

 Dr. Marey, Professor of the College of France, Paris. 



XL DIAGRAMS, MODELS, PREPARATIONS, AND 

 OTHER APPLIANCES FOR INSTRUCTION IN 

 BIOLOGY. 



3808. Recent Marine Mollusca. Typical collection, com- 

 prising 300 genera; to illustrate Woodward's "Manual of the 

 Mollusca," and other works. R. Damon. 



3809. Land and Fresh Water Mollusca. Typical collec- 

 tion, comprising 155 genera; to illustrate Woodward's "Manual 

 of the Mollusca," and other works. R. Damon. 



3810. British Marine Shells, illustrative of Dr. J. Gwyn 

 Jeffreys's " British Conchology." 336 species. R. Damon. 



