RECREATIVE SCIENCE. 



93 



trembling without progressing, or perfectly 

 motionless, or gliding round in a direction 

 contrary to tliat of their real motion. These 

 frequently recurring and illusory changes 

 excite the curiosity, give animation to the 

 pictures, and confer an ethereal brightness, 

 vivacity, and splendour upon them, which is 

 altogether and peculiarly their own. 



In the preparation of the discs intense 

 washes of these pigments are chosen, and as 

 few are required to produce an almost incal- 

 culable number of changes, the rationale of 

 the colour-top is as simple as that of the 

 kaleidoscope ; and, in the production of 

 colours by it, we are enabled to refer such 

 colours to their constituents, and thus have 

 a key to the mixing of colours for every pur- 

 pose required by art. It is strange, however, 

 that though red and yellow produce orange 

 by rotation, and full tones and half tones 

 result in others intermediate between them, 

 yellow and blue, however proportioned to 

 each other, have never yet produced even a 



tolerable green. This fact stands in the way 

 at present of any attempt to form a nomen- 

 clatm-e of colours which shall have any philo- 

 sophical value. In all other respects the 

 colour-top illustrates the laws of contrast, 

 evokes the complementaries, and enables the 

 operator to blend colours in softer gradations 

 than can ever be accomplished by the pencil. 

 Indeed, for merely visual effects, and as 

 giving an index to the action of colours, hues, 

 tints, and shades, upon each other, it obviates 

 the necessity of mixing pigments until it has 

 determined previously the nature of the 

 mixture required for any given tone in all 

 the range of colouring, with the strange ex- 

 ception of the tones of green. Let us hope 

 that this exception may some day be found 

 capable of explanation ; at present it is a 

 mystery . 



Messrs. Smith, Beck, and Beck, 6, Cole- 

 man Street, and Messrs. Elliott Brothers, 30, 

 Strand, are the accredited agents for this 

 curious and instructive instrument. 



WINTER MANAGEMENT OF CAGE-BIRDS. 



The time has come when the best of friends 



must part. Our " herald of the sky " is now 



silent — our free denizens of the woods and 



forests have sung almost all their songs, and 



thoroughly enjoyed their holidays. They are 



soon about to bid us adieu for the season ; 



many of them bound on a return-visit to a 



foreign land, and the remainder collecting 



themselves into families. All we see out of 



doors tells us that Summer is gone ! 



" Yon glittering asters, with their radiant hues, 

 Convey the last memorial of her reign " — 



a reign that will not soon be forgotten. Yes, 

 Summer, glorious Summer, has departed. 

 All hail to her successor, Autumn ! 



" In rosy triumph he came laughing in, 

 Waving his golden hair." 



And have we not, all, felt and enjoyed his 



magic power, delighted in his lavish bounties, 

 and revelled in boundless luxuries of fruit 

 and flowers — aU- of his own providing P Of 

 course we have. A wee while longer he will 

 gladden our hearts ; and then — hurrah for 

 brave, sturdy Old Winter. 



Already the mornings are bright and 

 fresh ; already the air is clear and clasping. 

 The red leaf trembles on the spray ; the wind 

 warbles and sighs among the branches of the 

 trees. Nature is unrobing ; her wardrobe is 

 about to be laid aside. Her jewels — how 

 simple, and yet how beautiful ! Each separate 

 article of her toilet — how artless, and yet how 

 lovely ! Oh that we could, all of us, take a leaf 

 out of her ladyship's Book of Beauty. What 

 must she think of us her children, I wonder ! 



This change in the season has duly 



