580 EVERYDAY SCIENCE 



PROJECT XVI. How to Remove Dents in Wood, 

 pages 64-67 



A heavy blow of a hammer will leave a dent in wood. What 

 happens is that the molecules of the wood at this particular place 

 have been forced into smaller space; that is, the spaces between 

 them have been lessened (see p. 67 of this book). If the wood 

 had been as elastic as rubber, the molecules would have regained 

 their original positions immediately; but wood has not great 

 elasticity. 



If now we can cause the wood to absorb enough heat and moisture, 

 the molecules will be driven back to their original relative positions. 

 Heat an iron very hot. Soak several thicknesses of soft brown paper 

 in hot water. Lay this pad of wet paper over the dent and cover 

 it with a double thickness of cloth soaked in hot water. Apply the 

 hot iron to the cloth just above the dent, and let it stand until the 

 cloth and paper are nearly dry. If the dent is deep, this process 

 may have to be repeated several times. 



PROJECT XVII. How a Boy Scout Makes Fire without Matches, 



page 72 



Five things are necessary to produce a rubbing-stick fire : a drill 

 or spindle, a fire-block or hearth, a hand-socket, a bow, and tinder. 



FIGURE 5 



In choosing wood for making the drill and fire-block, great care 

 must be exercised. The wood should be dry and long-seasoned, 

 but sound. Gummy and resinous woods should be avoided. A test 

 for good wood for this purpose is that the wood-dust ground off 

 shall h,e smooth to the touch, not gritty or sticky. Two of the 

 best and most widely distributed woods are cottonwood and willow. 

 Better even than these are the cedar, the cypress, or the tamarack, 

 if they can be had. If none of these is at hand, try soft maple, elm, 

 poplar, sycamore, or buckeye. 



