436 



Popular Science Mont/ili/ 



A Fascinating Old Sport in a 

 New Dress 



AN inlerestiiig outdoor game may !«■ 

 evolved from the simple act of 

 tossing a wooden spear at a moving ring. 

 A conveniently located tree, f)r a cross- 

 arm of scantling may be 

 used to suspend it. The 

 rope is tied to the cleat C 

 and passes through sev- 

 eral eyes or guides. At 

 the end, the small stick 



The Ring Is Set Swinging and the Spear 

 Is ToEsed Through It From a Distance 



B is tied. The ring ^ is a piece of spring 

 wire which snaps on to the stick. The 

 spear is a broom-handle or straight pole 

 with one sharp end. The ring is set swing- 

 ing with a gentle penrlulum-like motion 

 and the one about to test his skill endea\ - 

 ors to toss it through. If it touches the 

 ring another trial is allowed, and if it passes 

 through cleanly ten points are scored. 

 As skill increases the throwing dis- 

 tance may be lengthened. After 

 passing through the ring one point is 

 scored for every five feet the spear 

 travels. If it is of this length it will 

 be easy to measure and count the 

 points. The sport is fascinating and 

 admits of nnich variation in scoring. 



Tracing Magazine Cuts 



THE cut is traced on a clean, unused 

 sheet of carbon paper with a sharp 

 pencil. The j)rii]ts are then made from 

 the carbon sheet; they will be blue lines 

 on a white background. By this method 

 it is possible to pencil additional notes 

 on to the print. The carbon sheets can 

 be used as long as necessary and then 

 renewed by holding them against anv 

 hoi surface such as an electric globe. 

 This will melt the c.irbon preparation 

 and soon cover all the lines. 



Measuring Ten Thousandths 

 of an Inch 



THK accompanying illustration shows 

 the essential parts of a micrometer 

 designed to indicate on a scale S the 

 thickness, in thousandths of a millimeter 

 (one millimeter is about one twenty-fifth 

 of an incli) of any small object placed 

 between two tempered steel blocks, 5, 

 and B2- 



\n using the instrument the blocks 

 Bi Bo are first brought together without 

 obstacle, and then the micrometer screw 

 is turned in one direction or the other 

 until / stands at zero on .S. A button is 

 then pressed to turn the lever about the 

 pivot A and permit introduction of the 

 body to be measured between Bi B^. 

 The screw T is then rotated as far as neces- 

 sary to make the spring e.xert a suitable 

 pressure on the piece between B^ B2. 



Between the block B^ and a fixed 

 block C there is stretched a wire between 

 the centi-r point of which and a second 



N=<C3 



Esr.cntial Parts of a Micrometer That In- 

 dicates Thickness in Thousandths of a 

 Milhmeter on a Finely Balanced Scale 



block E there is stretched a second wire 

 DE. The wire FG is attached to the 

 center of DK and, after i>assing round a 

 pulley P on the point spindle it (FG) is 

 anchored to a plate spring K. The 

 latter keeps taut the wires GF, ED and 

 B-, (', hence as B2 moves to the left 

 (when a |)iece to be measured is intro- 

 ducetl between B^ Bo or the zero of the 

 instruments is adjusted), the slack in 

 Bo C is taken up by the sag of the wire 

 being increased. Slack thus produced 

 in I')!', is taken u|) by incri'ased sag at 

 /•', the spring A' meanwhile "nn)ving to the 

 Kll to take up slack in FG. 



