820 SEC. 18. BIOLOGY. 



7. Explorator for determining the rapidity of the flow of fluids. 



8. Explorator for determining the changes in the size of the 

 hand. 



8a. Explorator for determining the changes in the size of the 

 heart of the tortoise. (Plate 8 and 8 bis.) 



9. Apparatus of " Donders " for verifying the correctness of 

 tympana. 



10. Myograph for transmission. 



11. Myograph, direct, double. 



12. Myograph, direct, single. 



13. Myograph of the heart. (For these 3 apparatus, Plate J2 

 to 12 3 .) 



14. Explorator of the movements of liquids in an elastic tube. 

 (Plate 14 and 14 bis.) 



15. Explorator for investigating the pressure of the foot in 

 human progression. 



15A.J 



15B. > feet of the horse. 



ISc.J 



16. Apparatus for showing the action of muscular elasticity. 



17. Tracing on paper transferred direct to wood. 



18. Registering cylinder, with " Foucault " regulator, and rota- 

 tory hopper, by Marey. 



19. Tympanum and lever recording instrument. 



20. Haemodromograph, by Chauveau. 



21. Portable electric chronograph. 



22. Tambours conjugues, for reproducing movements at a 

 distance. 



23. Pantograph of transmission, for reproducing movements at 

 a distance. 



7. For demonstrating the laws of vision : 



Large glass model of human eye ; stereoscope and geo- 

 metrical slides, to show effect of binocular vision. 



8. Diagrams of 



(a.) Shadow and penumbra. 



(.) Lateral inversion of reflected image. 



(c.) Distance of image behind mirror. 



(d.) Refraction by prism. 



(e.) convex lens and formation of image. 



(/) concave 



(g.) The human eye. 



The foregoing set is contained in a strong case, 

 24 x 18x9 inches, with fittings for facilitating 

 the employment of the apparatus. 

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



