Fruit-growing 



273 



remove the vessel from the heat and allow any sediment to settle to the 

 bottom. When the liquid is cool dip and strain off the top, or red por- 

 tion, and save for future use. 



For the out-door exercise build up two piles of stones about a foot 

 high and four feet apart, lay the two iron rods from one pile to the 

 other, spacing the rods to form a sup- 

 port for the tub. Place the tub on 

 the rods and pour the water into it, 

 build a fire, and proceed with the 

 boiling as directed for the laboratory 

 exercises. 



With two washtubs used for boiling 

 the solution it is possible to make 

 enough concentrate in a day to keep 

 busy a crew with a hand sprayer 

 fitted with two leads of hose. Five 

 boys could make the spray and do 

 the work of spraying an orchard ; two 

 boys to make the lime sulfur solu- 

 tion, one boy to work the hand pump ; 

 two boys to hold the two leads of 

 hose. 



2. Testing lime sulfur solution. 

 The density, or strength, of lime 

 sulfur solution is tested by means of 

 an hydrometer, an instrument made 

 to measure the density of liquids. 

 Two kinds of hydrometers are in use 

 one marked to read according to 

 the Baume scale and the other to 

 read specific gravity direct. The 

 specific-gravity type is more con- 

 venient for the orchardist, although 

 by means of a table, Baume readings 

 can be reduced readily to specific- 

 gravity readings. Instruments are 

 made, also, on which both scales are 

 marked. Fig. 117 shows at a cylinder for liquid to be tested, at 6 spe- 

 cific-gravity hydrometer, and at c Baume hydrometer. Hydrometers 

 can be purchased from dealers in laboratory supplies. 



Use some of the solution made in the previous exercise ; also secure 

 a quantity from an orchardist or from a dealer. Have the liquid 60 F. 

 T 



FIG. 117. Apparatus for determin- 

 ing specific gravity of lime sulfur 

 solution, a, Cylinder for liquid 

 to be tested ; 6, specific-gravity hy- 

 drometer ; c, Baume hydrometer. 



