754 



Popular Science Monthly 



Fig. 2. A 

 mother 

 top and 

 her brood 



Fig. 3. A ball 



which spins or 



rolls on a wire 



Fig. 4. A top which 

 climbs its string 



Fig. 5. A colored wind- 

 mill top spun by air 



Mechanical Tops 



SPINNING-TOPS, like toy soldiers 

 and other necessities of boyhood, 

 have existed for many years. Re- 

 cently, the old standby made from a 

 spool with a peg pushed through the 

 center, has succumbed to more scientific 

 devices. The principle of the gyroscope 

 is frequently used. The little ballet 

 dancer. Fig. i, can spin on her foot, her 

 arm or her head, because of the gyro- 

 scope mechanism which is concealed in- 

 side it. 



A toy which resembles an old hen and 

 her brood of chickens, consists of one 

 large top having several lateral cavities 

 with small tops mounted in them, Fig. 2. 

 When the big top is spun, a disk at- 

 tached to its shaft rotates also, and the 

 outside of this disk, touching each of the 

 small tops, causes them to spin. 



Jugglers and acrobats have a ball 

 which will balance on a wire, resist all 

 efforts to roll it, or roll in only one 

 direction. Fig. 3. The gyroscope prin- 

 ciple is involved in this toy. 



Another top for balancing on a wire 

 has an egg-shaped case with a removable 

 cap. Fig. 4. The mechanism, enclosed 

 within this case, spins in a tiny depres- 

 sion. The case is mounted on a minia- 

 ture truck of two wheels. 



The principle that a whirling body 

 tends to rotate about its shortest axis is 

 demonstrated in a toy consisting pri- 

 marily of a blow-mill encased in a 

 circular tin box. Fig. 5. Attached to 

 the axis of the fan is a long cord ter- 

 minating in a hook. When the fan is ro- 

 tated, the cord becomes rapidly twisted. 

 A ring suspended from the hook will 

 rotate in a horizontal position. 



Variations from the simple ring may be 

 used, one being a ring having a con- 

 centric disk of primary colors. Rapid 

 rotation tends to resolve the colors into 

 white. The opposite phenomenon may 

 be illustrated by means of irregular 

 pieces of white cardboard with holes 

 punched in them; they tend to break up 

 white light into colors. 



One of the newest ideas in toys is a 

 real musical top. Fig. 6. A hollow cone 

 has a vertical shaft projecting beyond 

 the upper rim and having a central hole 

 in which a nail may be inserted for 



