The double hydrometer test is performed for the dispersivity index of the soil particle. But before we perform this test, the soil particle need to be passed through Sieve no #200 (0.075 mm). There are two methods of passing the soil particles, by washing the soil and oven drying the soil sample and by crushing the soil particles and by passing the dry soil through Sieve no #200.
Which method should be adopted for the Double hydrometer test?