13. Glass models of crystals (60), contained in two 

 cases. 



1886. Exhibited by F. E. Becker tf Go. 



Includes solids which are not possible crystalline forms, though 

 symmetrical. 



C. Models in other Transparent Substances. 



14. A tetrahedron in transparent mica, with the corre- 

 sponding octahedron within in cardboard. The faces of 

 the octahedron which correspond to the tetrahedron 

 shown are coloured in dark blue, the others in light 

 blue. 



1876. Lent by Eev. N. Brady, M.A. 



15. Models in transparent horn (34) of German manu- 

 facture. 



E. 19. 1858. Presented by the Society of Arts. 



The crystallographic axes are marked by threads within, 

 visible through the horn. Two of them contain second forms, 

 viz., the octahedron and rhombic dodecahedron within the cube. 

 10 represent the cubic system, 4 the tetragonal, 6 the rhombic, 

 9 the hexagonal, 3 the oblique, and 2 the anorthic. 



D. Wood Models. 



16. Set of wood models to illustrate the five regular 

 solids. 1-| in. size. In mahogany box. 



1873. Exhibited by J. E. LarJcin. 



17. Set of models of crystals similar to No. 16, but 

 of 1 in. size. 



1873. Exhibited by J. R. LarJcin. 



18. Set of half -inch wood models (14), in glass case, 

 representing the fundamental forms and most important 

 combinations in the six systems of crystallography. 



1873. Exhibited by J. E. LarJcin. 



19. Models of crystals in wood (42). f in. size. In 

 mahogany box. To illustrate Dana's Mineralogy. 



1874. " Exhibited by J. E. LarJcin. 



