THIRTY USEFUL DEVICES 103 



The force pump should have nozzle and valves coarse 

 enough for use in whitewashing. With rather thin 

 whitewash and a pump, the interior of a lousy hen- 

 house can be coated in a few minutes. Outside white- 

 washing can also be done" in this way. A force pump 

 is good for applying kerosene emulsion where lice, 



FIG 98 : SCREW PULLEY 



FIG 99 : HOMEMADE PULLEY 



nest bugs or fleas are very plenty. The emulsion is 

 made by adding kerosene oil to soapsuds and shaking 

 them together in a covered pail until they mix, or by 

 pumping them a fe\v times from one pail to another. 

 For applying disinfecting solutions of sulphuric acid 



