  We study the ultraviolet behaviour of the ghost and gluon propagators in
quenched QCD using lattice simulations. Extrapolation of the lattice data
towards the continuum allows to use perturbation theory to extract
$\Lambda_{\text{QCD}}$ - the fundamental parameter of the pure gauge theory.
The values obtained from the ghost and gluon propagators are coherent. The
result for pure gauge SU(3) at three loops is $\Lambda_{\ms}\approx
320\text{MeV}$. However this value does depend strongly upon the order of
perturbation theory and upon the renormalisation description of the continuum
propagators. Moreover, this value has been obtained without taking into account
possible power corrections to the short-distance behaviour of correlation
functions.
