192 TREES AS GOOD CITIZENS 



ferent lines. This substance kills by suffocation and is 

 used against borers, by injections into the openings of their 

 tunnels. The vapor of carbon disulphid is heavier than 

 air, and when it is injected the vapor sinks. The injection 

 is made by using a squirt oil can or a dropper, such as is 

 employed in- filling fountain pens. After the injection has 

 been made the hole must be promptly plugged with some 

 such material as grafting wax, putty or soap, to prevent 

 the escape of the vapor. Carbon disulphid must be handled 

 with care. It is highly inflammable and, when inhaled freely, 

 it is poisonous. 



Spraying Apparatus. For use in spraying small trees 

 a hand atomizer is adequate. In general appearance this 

 resembles a tire-pump. It is made of copper, brass or 

 heavy tin, and holds about a quart of liquid. 



A small compressed-air pump is convenient for spray- 

 ing operations on a small scale. This pump resembles the 

 fire extinguishers seen in factories and office buildings. It 

 is made of brass or galvanized sheet steel, and holds from 

 3 to 4 gallons. It is carried by means of a shoulder strap. 

 In preparing it for use the liquid is poured into the tank, 

 the opening closed and air pumped in to provide pressure 

 for forcibly expelling the liquid. 



A barrel hand-pump outfit, holding approximately 50 

 gallons, may be used for spraying a limited number of 

 moderate sized trees like apple trees. The working parts 

 of the pump must be of non-corrosive metal, such as 

 bronze or brass. The pump may be mounted on either 

 the head or side of the barrel, and the whole outfit placed 

 on a wagon or on skids, for convenience in moving from 

 tree to tree. 



Next in size and capacity above the barrel hand-pump 

 outfit is the double action hand-pump, employed with 

 150 or 200 gallon tank, the tank mounted on the running 



