The conductance of filamentary silver azide crystals initiated by a la
ser pulse is measured concurrent with their emission and acoustic sign
als. It is shown that the conductance pulse is 50-70 ns ahead of the e
xplosion on the time scale, and the conductance of the samples approac
hes that of a metal. It is concluded that explosion proceeds by the ch
ain mechanism. A plausible model of the chain process is proposed.