Popular Science Monthhf 



249 



Cleaning Five Hundred Black- 

 board Erasers at a Time 



EVERY school teacher knows 

 how difficult it is to keep the 

 blackboard erasers clean, and to 

 prevent chalk dust from being 

 thrown out into the air of the 

 school-room, where it must be 

 breathed by the pupils. To rem- 

 edy this, a machine has been in- 

 vented which cleans five hundred 

 erasers without throwing dust 

 into your eyes and nose. 



It consists of a revolving drum 

 of hea\'y %\-ire netting or perfo- 

 rated iron, inclosed in an outer 

 casing. The erasers are placed in 

 the drum, which, as it revolves slowly, 

 bumps them about and extracts the dust. 

 At the same time, a rapidly revolving fan 

 draws a current of air over the erasers, 

 causing the chalk dust to be gathered up 

 and wafted away through a pipe opening 

 into a chimney or convenient ventilating 

 flue. The machine is run by a motor. It 

 not only cleans the erasers thoroughly, but 

 keeps the felt in excellent condition. A 

 machine, similar to the one shown, works 

 by a handle and crank. It cleans one 

 hundred erasers at a time. 





When the chalk dust is shaken from the erasers, 

 it is drawn off through a ventilating flue 



Hooking eels through the ice. It is not as easy as it looks. 

 Try it some winter's day and you will be convinced 



You Don't Spear Eels in Winter— 

 You Hook 'Em 



SPEARING eels at night under the 

 glare of a lantern or pot of fire 

 fastened over the water to the bow of a 

 boat, is an enjoyable summer and winter 

 sport. In summer, eels are jabbed with a 

 three-barbed spear. In winter they are 

 taken with an eight-tined hook. It takes 

 about ten times as much labor and pa- 

 tience to hook an eel through the ice as it 

 does to jab one through 

 the open water. Try it 

 some cold winter's day 

 and you will be con- 

 vinced. 



After the hole has 



been cut or dug through 



the ice, the eel hunters 



stand ready with their 



poles, waiting for their 



prey to come to the top. 



But the eels are not so 



anxious to come to the 



consequently the hunters 



to reach down into the 



water and to hook any curious victim 



that may unwarily wriggle along to its 



fate. 



As a rule, the poles are held stationary 

 until an eel swims a few inches above 

 the hooks. When the hunter has 

 gaged the distance correctly, he gives a 

 quick upward movement to his pole 

 and the eel is impaled and held fast. 

 During the winter nights, strange to 

 say, eels remain at the bottom of an 

 ice-covered stream. 



top as fish; 

 are obliged 



