114 



JOURNAL OF xVGRICULTURE OF P. R. 



The principal points to be guarded against daring storage are 

 evaporation, exposure to the air, and presence of acids, surplus lime, 

 or other chemicals ii\ the containers. Clean barrels may be used, 

 and if it is not possible to close them air-tight a layer of heavy oil 

 will protect the concentrate. This can be skimmed oif before using 

 the lime-sulphur. Changes in temperature will not aifect the mate- 

 rial. 



Dilution. — This is the most important point in the entire process of 

 using lime-sulphur, and is of equal importance whether the commercial 



brands or the home-made material be used. 

 Two solutions may appear to be the same, 

 but in fact may be found to vary greatly" 

 in density, so that unless dilution is properly 

 carried out, burning may result. A concen- 

 trate will change in density from time to 

 time due to evaporation, and it is therefore 

 essential that a test be made each time por- 

 tions of it are used. Safe and satisfactory 

 dilutions are obtained by the use of a simple 

 instrument known as the hydrometer (Fig. 

 23). These are made for a wide range of 

 uses, and hence to obtain best results one es- 

 pecially adapted for lime-sulphur work should 

 be used.^ The best type is graded in two 

 scales, the specific gravity or decimal scale, 

 and the Baume or degree scale. The concen- 

 tration of lime-sulphur solution is gener'ally 

 given in terms of tlie Baume scale but the 

 other is necessary in making the calculations 

 for final dilutions. 



To obtain a spray of any certain concen- 

 tration, obtain the density of the concentrate 

 M'itli the hydrometer, and then divide the 

 decimal of this i-eading by the decimal of 

 the density of the spray desired, and dilute according to the figure 

 obtained. For example, if tlie concentrate has a density of 1.283 

 (32^ Haume^ to obtain a spray solution of 1.02fi (a 1-10 spray) the 

 figure .283 is divided by .026, giving 10 plus, the number of dilutions. 



^ 



Fig. 2.3. — A lime-s\ilpliiir 

 hydrometer showiiifj the 

 Baume «cale. On tlie 

 right a cylinder of the 

 type sold with the in- 

 •strument. Any ves>el 

 of sufficient dej)th may 

 be used in its ])lace. 



' These may lie jjurchiisfd together with the cylinder for about one dollar from the 

 Bausch and Lamb Optical Co.. Rochester. N. V.; Arthur Thomas, Philadelphia; Einier and 

 Amend Co., New York; iuid other dealers in scientific supplies. 



