PREFACE 



A.BOUT the year 1851 there was placed at my disposal a 

 Lantern, of a character very unusual (at that time) for 

 any boy of my age to possess a share in ; in fact it was 

 one of Carpenter and Westley's * Phantasmagoria ' 

 lanterns, unrivalled at that period of transparent sheets 

 and sperm -oil. The result was that Optical Projection, in 

 its various forms, has been with me more or less a hobby 

 ever since ; less followed for some years during which 

 pursuits of a more open-air character, 1 for sufficiently 

 serious reasons, engaged more of my attention, but 

 never abandoned, and again and again returned to with 

 renewed interest. Mere slides of course came first, but 

 I soon discovered for myself that things could be pro- 

 jected as well as pictures ; and for a long time past I 

 have found much relaxation from my literary work, in 

 reducing various optical and other physical experiments 

 to conditions which enable an audience to behold them 

 upon a screen, and in devising contrivances for making 

 the beautiful phenomena of Polarised Light more spec- 

 tacularly imposing. Since the publication of a little 



1 Poultry-breeding. 



