Example $3\mathrm{.}2$: In a specific gravity test, the weight of the dry soil taken is $0\mathrm{.}66$ N $.$ The weight

of the pyknometer filled with this soil and water is $6\mathrm{.}756$ N $.$ The weight of the pyknometer full

of water is $6\mathrm{.}3395$ N $.$ The temperature of the test is $30C.$ Determine the grain specific gravity,

taking the specific gravity of water at $30C$ as $0\mathrm{.}99568.$