64 History of Dr. Brewster's Kaleidoscope. [July, 



ley's instrument ; but this was never tried,* and for the best of 

 all reasons, because nobody would have purchased it. 



We trust that no person, who wishes to judge of this subject 

 with candour, will form an opinion without having actually seen 

 and used the instrument proposed by Bradley. Let any person 

 take Bradley's plates, and, having set them at an angle of 30° or 

 22i°, place them upon a cell containing fragments of coloured 

 glass, he will infallibly find that he cannot produce a picture of 

 any symmetry or beauty. The disunion of the sectors, the 

 darkness of the last reflections, and the enormous deviation 

 from symmetry, towards the centre of the figure, will convince 

 him, if he required conviction, that the instrument is entirely 

 useless as a kaleidoscope. To those, however, who are not 

 capable, either for want of knowledge or want of time, to make 

 such a comparison, we may present the opinion of three of the 

 most eminent natural philosophers of the present day, viz. the 

 celebrated Mr. Watt, Professor Playfair, and Professor Pictet. 



" It has been said here," says Mr. Watt, " that you took the 

 idea of the kaleidoscope from an old book on gardening. My 

 friend, the Rev. Mr. Corrie, has procured me a sight of the 

 book. It is Bradley's Improvements of Planting and Gardening. 

 London 1731, part 2, chap. i. It consists of two pieces of look- 

 ing glass of equal bigness, of the figure of a long .square, five 

 inches long and four inches high, hinged together, upon one of 

 the narrow sides, so as to open and shut like the leaves of a 

 book, which, being set upon their edges upon a drawing, will 

 show it multiplied by repeated reflections. This instrument I 

 have seen in my father's possession 70 years ago, and frequently 

 since ; but what has become of it I know not. In my opinion, 

 the application of the principle is very different from that of your 

 kaleidoscope." 



Postcsript to Prof. Playfair 1 s Letter. (For the Letter itself, see 



Annals, xi. 451.) 

 " P. S. — Granting that there were a resemblance between the 

 kaleidoscope and Bradley's instrument, in any of the particulars 

 mentioned above, the introduction of coloured and moveable 

 objects, at the end of the reflectors, is quite peculiar to Dr. 

 Brewster's instrument. Besides this, a circumstance highly 

 deserving of attention, is the use of two lenses and a draw tube, 

 so that the action of the kaleidoscope is extended to objects of 

 all sizes, and at all distances from the observer, and united, by 

 that means, to the advantages of the telescope. J. P." 



* In illustration of this argument, we may state (he following fact. Mr. C. of 

 Birmingham, being anxious to e^ad'- Dr. lir. wsier"s patent, at a time when the 

 manufacture of the patent kaleidoscope was in the hands of another person, attempt- 

 ed toconstruct instruments in imitation of Bradley's. After exercising his ingenuity 

 for some time, he abandoned the attempt as impracticable, and set oft' for Scot- 

 land for (he purpose of oftVring h:s services in manufacturing the patent instrument. 



