SHEEP TICK AXD ITS ERADICATION BY DIPPING. 29 



The slide board into the vat should be set at an angle of 45 degrees 

 and extend from the floor of the chute to at least 4 inches below the 

 dip line; it should be made of or covered with a smooth-surfaced 

 material, such as planed lumber or sheet metal. The end extending 

 into the dip should be flush with the vertical end of the vat. A space 

 between the slide board and the end of the vat, if large enough foi 

 a lamb to lodge in, is a dangerous arrangement. The runway leading 

 out of the vat should not be too steep. The length varies from 8 to 

 16 feet, the latter being preferable in large vats. 



HEATING FACILITIES. 



When lime-sulphur dip is used it is necessary to provide cooking 

 tanks. The cooking may be done b}^ steam or in open boilers having 

 a Are box under each. All large plants should have steam boilers 

 of not less than 25 horsepower. The live steam can be piped into 

 the dipping vat and used for maintaining the temperature of the dip 

 and also into the cooking and heating tanks for boiling the dip or 

 heating water. The steam pipes should extend along the floor of 

 the vat at least two-thirds of the length and be provided with open- 

 ings for the escape of the steam into the dip. The supply pipe from 

 the settling tank should enter the vat above the dip line in order 

 tliat any leak may be detected easily. The open-tank heating system, 

 if preferred, may be installed instead of the steam boiler. 



CARE OF PLANT WHEN NOT IN USE. 



A dipping plant that does not receive proper care when not in use 

 deteriorates very rapidly. The pressure of the ground against the 

 sides of the vat tends to cause them to bulge inward; this tendency 

 may be counteracted to some extent by keeping the vat full of liquid. 

 Wooden vats which are allowed to stand empty Avill dry out, and the 

 lumber will' shrink so that the vat will leak when refilled. At the 

 close of dipping operations the vat should be left full of liquid and 

 water added from time to time to restore that lost by evaporation. 



A week or 10 days prior to beginning dipping operations the entire 

 plant should be overhauled and put in good condition. Before charg- 

 ing a new vat or one which has stood empty for some time, it should 

 be filled with water to ascertain whether it leaks. 



CONSTRUCTION OF DIPPING PLANTS. 



Plans for construction of wooden and cement sheep-dipping plants 

 are shown in figures 14 and 15. They are not drawn to a uniform scale, 

 consequently in studying the drawing the scale of each part should 

 be noted. The plants as shown have no superfluous equipment, and 

 the arrangements are as simple as is consistent with efficiency. The 

 size of the plant can be increased or decreased as desired. A differ- 



