  The half-life of the $\alpha$ decaying nucleus $^{221}$Fr was determined in
different environments, i.e. embedded in Si at 4 K, and embedded in Au at 4 K
and about 20 mK. No differences in half-life for these different conditions
were observed within 0.1%. Furthermore, we quote a new value for the absolute
half-life of $^{221}$Fr of t$_{1/2}$ = 286.1(10) s, which is of comparable
precision to the most precise value available in literature.
