492 Mr. C. V. Boys on the Production, Properties, 



once supply a ready means of instantly producing a very high 

 velocity, which the arrow maintains over a considerable dis- 

 tance. For the special purpose under consideration, the 

 lightest possible arrow is heavy enough. I have made arrows 

 of pieces of straw, which may be obtained from wool- shops, 

 a few inches long, having a needle fastened to one end for 

 a point. Arrows made in this way travelled the length of 

 the two rooms in which I made these experiments — about 

 90 feet — in what seemed to be under half a second. They 

 completely pierced a sheet of card at that distance, which I 

 put up thinking that a yielding target might damage them 

 less than the wall, and were then firmly stuck unharmed in the 

 wall behind ; in every way they behaved so well that I do 

 not think a better make of arrow possible. 



The bow I used was a small cross-bow held in a vice 

 with a trigger that could be pulled with the foot. The first 

 bow was made of oak, the first wood that came to hand. I 

 then made some bows of what was called lance-wood (it was 

 unlike any lance-wood I have seen) ; but the trajectory was 

 at once more curved, the arrow took perceptibly longer to 

 travel, and the threads produced were thicker. As the arrow 

 is so light, the only work practically that the bow has to do 

 is to move itself; that wood then which has the highest 

 elasticity along the fibres for its mass is most suitable ; in 

 other words, that wood which has the greatest velocity of 

 sound is best. I therefore made bows of pine, and obtained 

 still higher velocities and finer threads than I could obtain 

 with oak bows. 



With a pine bow and an arrow of straw I have obtained a 

 glass thread 90 feet long and joJoo mcn m diameter, so 

 uniform that the diameter at one end was only one sixth more 

 than that at the other. Pieces yards long seemed perfectly 

 uniform. 



A fragment of drawn-out glass was attached to the tail of 

 the arrow by sealing-wax, and heated to the highest possible 

 temperature in the middle, the end heing held in the fingers. 

 With every successful shot the thread was continuous from 

 the piece held in the hand to the arrow 90 feet off. The 

 manipulation is, however, difficult, but another plan equally 

 successful has the advantage of being quite easy. It is not 

 necessary to hold the tail of glass at all ; if the end of the 

 tail only be heated with the oxyhydrogen jet until a bead 

 about the size of a pin's head is formed, and the arrow shot, 

 this bead will remain behind on account of its inertia, and 

 the arrow go on, and between them will be pulled out the 

 thread of glass. 



