KINEMATIC MODELS. 



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former merely by increasing the lengths of two of its links, making 

 them equal and infinitely long. I particularly wish to draw your attention 

 to this chain, both because it is very familiar, and because by its 

 inversion, that is by fixing one or another of its links, we get such very 

 notable results. I have already fixed one link (Fig. 6), and you have 

 seen the common steam engine driving train. If I fix another link, say 



Figure 7. 



the connecting rod, we have a mechanism which I think you will at once 

 recognise as the driving train of the common oscillating engine (Fig 7). 

 This appears even more distinctly if we reverse the sliding pair 4, 

 making the link d carry the full prism, and the link c the open prism 

 (Fig. 8). The link c becomes the steam cylinder, d (which was the 



Figure 8. 



frame in Fig. 6) the piston and rod, and b (the connecting rod in 

 Fig. 6), the framing of the engine. 



