The graph shows a relationship between the log of \( \frac{x}{m} \) and the log of pressure. By applying the equation for the graph at the given pressure, we can calculate \( \frac{x}{m} \).
From the equation, we get:
\[
\log \left( \frac{x}{m} \right) = 0.477 \times \log (0.3)
\]
Using the known logarithmic values for \( \log (0.3) = 0.477 \), we compute the value of \( \frac{x}{m} \).
Thus, the value of \( \frac{x}{m} \) at the pressure of 0.3 atm is \( \boxed{0.6} \).