What is the sample density used for a buoyancy mass correction?

For a lab exercise to calibrate volumetric glassware I was given the follow equation to correct weighings for the density of air:


$$m\_\mathrm{c} = m\_\mathrm{s}\,\frac{1 - \rho\_\mathrm{a}/\rho\_\mathrm{c}}{1 - \rho\_\mathrm{a}/\rho\_\mathrm{s}},$$


where:


* $m\_\mathrm{c}$ is the corrected mass of the sample;
* $m\_\mathrm{s}$ is the measured mass of the sample tared for the container;
* $\rho\_\mathrm{a}$ is the density of air;
* $\rho\_\mathrm{c}$ is the density of weights used to calibrate the balance, assumed brass;
* $\rho\_\mathrm{s}$ is the density of the sample.


Does $\rho\_\mathrm{s}$ include the container for the sample? How is $\rho\_\mathrm{s}$ determined without knowing $m\_\mathrm{c}$?


If the tared container does not affect the calculation, $\rho\_\mathrm{s}$ for water is straightforward. What about other material?


