200 



Popular Science Monthly 



A new sound -producing device. These hollowed 

 cups cleverly imitate the clatter of a horse's hoofs 



Ashes From Burned Wood 

 Make a Good Fertilizei 



DO not bewail the fact that 

 the price of commercial 

 fertilizers has gone beyond the 

 reach of all except the wealthy- 

 farmer. It is because potassi- 

 um oxide, one of the important 

 ingredients of a good fertilizer, 

 has jumped from four hundred 

 to eight hundred dollars a ton. 

 But any farmer can proc^uce 

 his own potassium oxide from 

 the fresh ash of burned twigs, 

 branches and other parts of 

 such hardwood trees as the 

 beech, birch and maple. It is 

 a very simple process requiring 

 a cheap apparatus and no 

 complex chemical treatment. 

 The College of Forestry at 

 Syracuse will give information 

 to anyone about the process. 



Ripsaw 

 tee^h 



How the Cavalcade Approaches 

 Behind the Scenes 



EVERY barnstorming com- 

 pany has as not the least 

 important part of its equipment 

 a pair of hollowed cocoanut 

 shells, which in the hands of the 

 stage mechanic, sound more like 

 a horse than a horse itself. Now 

 that most of our melodrama 

 comes to us through the motion 

 pictures, along comes an imita- 

 tor of clattering hoofs to be 

 attached to a stationary organ. 

 It is operated from the keyboard 

 by a lever or button. With the 

 aid of a swell box, the sound can 

 be made to swell or diminish. 



The device consists of six 

 cups, the upper three of which 

 are secured to the bellows and 

 the lower three of which are 

 mounted on a solid base. To 

 operate them, the organ player 

 presses a key which causes the 

 first cup to come down with a 

 thud, followed in quick succes- 

 sion by the other two cups. 

 There is no break in the action. 

 The cups are made of maple. 

 The inventor is Harold A. Val- 

 kenburg, of Oakland, C'alifornia. 



Tlie toothed 

 sides trim away 

 enough wood to 

 keep the blade 

 from binding 



New Key Hole Saw Which Will Not 

 Jam or Bind 



ANEW saw has been invent- 

 ed by A. R. Brewer, of 

 Northport, Washington. It not 

 only has teeth along one edge, 

 as has an ordinary blade, but 

 the sides and upper surface are 

 toothed also. Made in this way, 

 the saw can cut itself out of 

 any predicament. The toothed 

 sides automatically trim away 

 enough wood to keep the blade 

 from binding as it goes down 

 into the cut. These same 

 toothed sides may be used as a 

 rasp to widen out laterally the 

 hole that is being made. 



The saw is designed for both 

 rip and cross-cut work. The 

 pointed end of the blade is chan- 

 neled out much like a reamer, 

 so that by giving it a twisting 

 motion, it is quite able to bore 

 its own way into the wood in 

 starting a hole. The chisel-like 

 handle provided at the other end, 

 facilitates this action because the 

 blade may be driven into the 

 wood with a mallet if the 

 twisting motion at the start 

 does not prove sufficient. 



