MAGNIFYING POWEli OF SHORT SPACES. 



the operation for artificial pupil, the newly-formed opening 

 will appear inverted and multiplied in the same way ; and 

 each image, instead of being circular as it is in the healthy 

 eye, will be seen to resemble the figure of tlie new and dis- 

 torted pupil. 



But in order to demonstrate the images which this instru- 

 ment is capable of presenting to the eye in the most satisfac- 

 tory manner ; instead of cutting holes in pieces of black pajjer, 

 a series of figures having a transparent body and a black out- 

 line may be painted on glass with Indian ink. For this 

 purpose round patches of ink, about the size of a fourpenny 

 piece, should be laid on the centre of each glass slip with a 

 camel's-hair pencil ; and, when dry, transparent figures of the 

 required shape and dimensions can easily be made by erasing 

 a portion of the ink with a finely-pointed and slightly-moist- 

 ened wooden style. 



The forms of such transparencies will suggest themselves 

 to the ingenuity of the reader, but a few are subjoined by way 

 of example (figs. 18 to 33). 



Fig. 18. 19. 



20. 21. 22. 23. 24. 25. 





Fig. 26. 



27. 



28. 



29. 



30. 



32. 



Such forms arrange themselves into two groups ; those, for 

 instance, which are entire in themselves, and which constitute 

 elegant designs by their multiplication and the shifting of 

 their relative position (figs. 18 to 25), and those again which 

 are imperfect figures, but which produce entire compositions 

 of great beauty by their combination (figs. 26 to 33). 



