i:i, IIKATIN : -;CE. 



RECREATIVE SCIENCE. X I X . 



TUX COLOUR-TOP, INVENTED AFTER MR. HOSE'S OPTICAL 

 CONTRIVANCE CALLED TUB KALOTROPB. 



i NO about tho streets of the Hague one day, the writer 

 mot with a moat excellent and cheap toy, combining tho ordi- 



:Toota of persistence with the various changes of colour 

 !.- by u^ing a disc upon which red, yellow, and blue are 

 p.i:::ti-.l in unequal proportions, and exposed to view through an 

 [..snug in an opaque disc working upon but independently of 

 the coloured one. Thin top, under various denominations, has 

 been sold throughout England, and has, in fact, become quite a 



delight the inquiring mind* of a certain morbidly-inclined olaM 

 of philosophers, as w shown in Fig. 5 ; a TOM (Fig. 6), rational/ 

 shaped bottle* (Figs. 7 and 8), a goblet (Fig. 9), a tea-cup 

 and saucer (Fig. 10), and a champagne glaai (Fig. 



Thus by ingeniously modifying the old expedient* of moving 

 in a circle tho lighted stick, or the more brilliant effect* obtain, 

 able from certain fireworks, such u squib* or fire-wheel* in 

 which a revolving point of light produces toe effect of a wheel 

 of fire emitting sparks are these very entertaiuing and (Cor 

 children) harmless illustrations of persistence of vision produced. 



Tho idea of making colour topi, called kaleidoscope topt, 

 chameleon tops, cinephantic tops, trocheidoscopes, etc. all of 



"household toy. In Fig. 1 is shown the mode of winding tho 

 top, and in Fig. 2 the spinning is easily managed by holding 

 the wire inserted in tho hollow central axis and pulling away 

 the string with the other hand. Tho colours of the painted 

 disc are made to change rapidly by touching the top opaque 

 disc, and whatever colours then predominate give the prevailing 

 tints to tho revolving disc, in a manner that will be explained 

 more carefully when Mr. King's revolving coloured disc for tho 

 oxyhydrogen light is described. 



The toy is made still more amusing by the insertion into the 

 hollow and central axis of tho top, wires bont into various forms. 

 Thus tho wire (a) and disc (b) of Fig. 3 will produce Fig. 4. Another 

 wire, bent into the form of the profile of tho face, when spinning 

 round appears like some of those horrible casts of celebrated 

 homicides whose physiognomic and phrenological developments 



143 N.E. 



which owe their effects to open- work or perforated discs running 

 over coloured ones may be traced back to the first beautiful 

 contrivance invented by Mr. Thomas Rose, of Glasgow, called 

 the Kalotrope, or beauty-turner, which was exhibited by the 

 writer for the first time in London at tho Royal Polytechnic in 

 the early part of the year 1856, its leading features (to use the 

 words of the inventor) being the multiplication, combination, 

 and involution of simple figures into compound devices of singu- 

 lar beauty, both as regards form and variety of tint. 



The instrument consists of two concentric wheels, two feet 

 in diameter, working nearly in contact, and in contrary direc- 

 tions, and with equal or varying velocities. The movement is a 

 combination of wheels, by which a velocity of at least 1,000 

 revolutions per minute can bo obtained. Discs of devices are 

 provided for tho hinder wheel (corresponding to the disc of a 



