Abstract The compounds m-and p-(Me 2 CCH 2) C 6 H 4 SiMe 3 have been synthesized, and the rates of their cleavage by aqueous-methanolic perchloric acid have been measured and compared with those of the corresponding m-and p-(Me 3 SiCH 2) C 6 H 4 SiMe 3 compounds. The results show that the inductive release of electrons to a saturated carbon atom is markedly greater for the Me 3 Si than for the Me 3 C group.