A 500 g sample of dry soil was used for a combined sieve and hydrometer analysis (152 H type hydrometer). The soil mass passing through the 75 μ sieve = 120 g. Hydrometer analysis was carried out on a mass of 40 g that passed through the 75 μ sieve. The average temperature recorded during the test was 30°C.
Given: \left.G_{s}=2.55, C_{m} \text { (meniscus }\right)=0.50, C_{o}=+2.5, \mu=8.15 \times 10^{-3} poises.
The actual hydrometer reading R_{a}=15.00 after a lapse of 120 min after the start of the test. Determine the particle size D and percent finer P^{\prime} \% \text { and } P \%.