I. SPECIAL COLLECTIONS. 133 



17. Spheric involute. 



Katio 1:3. 



18. Spheric involute. 



Ratio 8:9 ; the curve in red is a curtate involute. 



1 9. Apparatus for describing spheric cycloids. 



Describes, among other curves, those here exhibited. 



554. III. Simple Kinematic Chains and Mechanisms. 



20. Quadric cylindric-crank chain. 



21. Slider-crank chain. 



22. Quadric conic-crank chain. 



23. Reduced slider-crank chain. 



The link c omitted. 



24. Reduced slider-crank chain. 



Links a and c omitted. 



25. Reduced conic-crank chain. 



The link c omitted. 



26. Quadric crank chain with slot and sector. 



27. Single crossed slide chain. 



28. Double crossed slide chain. 



29. Simple spur-wheel chain. 



30. Simple spur-wheel chain with annular wheel. 



31. Endless screw. 



32. Stand for carrying the above models when in use. 



555. IV. Crank Trains. 



33. Double slider-crank. 



34. Slider-crank. 



With ceutroids. 



35. Slider-crank. 



With centroids. 



36. Double slider-crank. 



With centroids. (The centroids are here Cardan's circles.) 



37. Slider-crank. 



38. Skew double slider-crank. 



39. Double slider-crank with curved slide. 



40. Double slider-crank with skew slide. 



41. Lever-crank. 



42. Double slider-crank with curved slide. 



With pin expansion. 



43. Slider-crank. 



Link b is here a disc. 



44. Slider-crank. 



With adjustable connecting rod. 



45. Slider-crank. 



With adjustable cross-head. 



