148 APPLICATIONS OF CENTRIFUGAL FOECE. 



line g li is an arc of a circle described from the point i with radius i g, 

 which is equal to the radius ed of the top piece ; 3rd, The knife must 

 cut through the card-board along all lines drawn full in the figure ; 

 but not much more than half through along the dotted lines ; 



the lines marked thus . - are not to be cut at all ; they are 



merely to facilitate the correct drawing of the figure on the card- 

 board, before cutting it out ; 4th, The piece ~bc r s is glued with its 

 whole surface upon the piece adpq, after the edges l>c and a g have 

 been sharpened with the knife, as shown in fig. 104 B ; the strip 



T e 



FIG. 104 (A i real size ; 2? real size). 



should be bent with the hand, as nearly as possible, in the form which 

 it is to have afterwards. The piece 1) cr s is required for giving firm- 

 ness, which would be wanting ifrs were glued upon a d immediately, 

 there would also in that case probably be an angle at the joint ; 5th, 

 The portions which are to be glued upon one another are marked by 

 the same figures ; 6th, For a cap of 16 em in diameter, the following 

 are the dimensions of the various parts in the figure : 

 d e = g i = 8 cm '5 ; a d = I c = 10 cm> ; e f 2 cm<r > 

 d r = a s = 54 cm '5 -,mn= lk = 2 cm *. t > ; r u = 7 cm> 4 

 c r = I s = 2 cm '5 ; m I = n o = 2 cm '0 ; a q = s t 2 om> 5. 



The apertures for the cord of the whirling-table are 4 cm high } and 

 2 cm wide. The whole will be more durable if pieces of thin linen 

 are glued over the joined parts, and by pasting some glazed paper 

 all over it, the cap may be made to look neater. 



The centrifugal railway shows a curious effect of the 

 same force. Fig. 105 represents the essential part of 

 it, namely, a grooved rail having a V-shaped section ; 

 the upper part forms a straight incline, while the 



