  We present new estimates of protosolar elemental abundances based on an
improved combination of solar photospheric abundances and CI chondritic
abundances. These new estimates indicate CI chondrites and solar abundances are
consistent for 60 elements. We compare our new protosolar abundances with our
recent estimates of bulk Earth composition (normalized to aluminium), thereby
quantifying the devolatilization in going from the solar nebula to the
formation of the Earth. The quantification yields a linear trend $\log(f) =
\alpha\log(T_C) + \beta$, where $f$ is the Earth-to-Sun abundance ratio and
$T_C$ is the 50$\%$ condensation temperature of elements. The best fit
coefficients are: $\alpha = 3.676\pm 0.142$ and $\beta = -11.556\pm 0.436$. The
quantification of these parameters constrains models of devolatilization
processes. For example, the coefficients $\alpha$ and $\beta$ determine a
critical devolatilization temperature for the Earth $T_{\mathrm{D}}(\mathrm{E})
= 1391 \pm 15$ K. The terrestrial abundances of elements with $T_{C} <
T_{\mathrm{D}}(\mathrm{E})$ are depleted compared with solar abundances,
whereas the terrestrial abundances of elements with $T_{C} >
T_{\mathrm{D}}(\mathrm{E})$ are indistinguishable from solar abundances. The
terrestrial abundance of Hg ($T_C$ = 252 K) appears anomalously high under the
assumption that solar and CI chondrite Hg abundances are identical. To resolve
this anomaly, we propose that CI chondrites have been depleted in Hg relative
to the Sun by a factor of $13\pm7$. We use the best-fit volatility trend to
derive the fractional distribution of carbon and oxygen between volatile and
refractory components ($f_\mathrm{vol}$, $f_\mathrm{ref}$). We find ($0.91\pm
0.08$, $0.09 \pm 0.08$) for carbon and ($0.80 \pm 0.04$, $0.20 \pm 0.04$) for
oxygen.
