  We have measured the half-life of the superallowed 0+ -to- 0+ beta+ emitter
26Si to be 2245.3(7) ms. We used pure sources of 26Si and employed a
high-efficiency gas counter, which was sensitive to positrons from both this
nuclide and its daughter 26mAl. The data were analyzed as a linked
parent-daughter decay. To contribute meaningfully to any test of the unitarity
of the Cabibbo-Kobayashi-Maskawa (CKM) matrix, the ft value of a superallowed
transition must be determined to a precision of 0.1% or better. With a
precision of 0.03% the present result is more than sufficient to be compatable
with that requirement. Only the branching ratio now remains to be measured
precisely before a +/-0.1% ft value can be obtained for the superallowed
transition from 26Si.
