o. In Bradley's instrument, 

 from the erroneous position of 

 the eye, there is a great in- 

 equality of light in the sectors, 

 and the last sectors are scarcely 

 visible, 



4. In Bradley 'sinstrument, the 

 figure consists of elliptical, and 

 consequently unequal sectors. 



5. In Bradley's instrument, 



History of the Kaleidoscope. 419 



3. In the kaleidoscope, the 



eye is placed so that the uni- 

 formity of light is a maximum, 

 and the last sectors are distinctly 

 visible. 



A. In the kaleidoscope, all 

 the sectors are equal, and com- 

 pose a perfect circle, and the 

 picture is perfectlvsymmetrical. 



5. In the kaleidoscope, the 

 equal sectors all unite into a 

 complete and perfectly symme- 

 trical fiijure. 



6. In the kaleidoscope, the 

 secondary reflections are en- 

 tirely removed, and therefore 

 no confusion takes place. 



7. In the kaleidoscope, the 

 eye is placed so that tlicse de- 

 fects of junction are invisible. 



theunequal sectors do not unite, 

 but are all separated from one 

 another by a space equal to the 

 thickness of the mirror ^lass. 



6. In Bradley's instrument, 

 the images reflected from the 

 first surface interfere with those 

 reflected from the second, and 

 produce a confusion and over- 

 lapping of images entirely la- 

 cunsistent with symmetrv. 



7. In Bradley's instrument, 

 the defects in the junction of 

 the plates are all rendered visi- 

 ble by the erroneous position of 

 the eye. 



The reader will observe, that in this comparison the two in- 

 struments are supposed to be applied to geometric lines upon 

 paper, and that this was the only purpose to which Bradley ever 

 thought of applying his mirrors; yet the kaleidoscope is in every 

 r^-'spect a superior instrument, even for that inferior purpose, and 

 gives true symmetrical forms, which the other instrument is in- 

 capable of doing. 



In the comparison which has now been made, we have de- 

 graded the kaleidoscope, by contrasting its effects with those 

 which Bradley's instrument is capable of producing, for these 

 effects are not v/orth the looking at. When we attempt to em- 

 ploy Bradley's instrument to produce the effects which have 

 been so much admired in the kaleidoscope, namely, to produce 

 beautiful forms from transparent or opaque coloured objects co!i- 

 tained in a cell, and at tlie end of the reflectors, it fails so en- 

 tirely, that no person has succeeded in the attempt. It is in- 

 deed quite impossible to produce by it the beautiful and sym- 

 metrical forms which the kaleidoscope displays. Had this been 

 possible, Dr. Brewster's patent might Jiave been invaded with 



Vol. :A. No.242. June ISIS. F f impunity 



