Infra-red spectra have been obtained in the C-H bond-stretching region for acetylene chemisorbed on the metals palladium and copper, and for ethylene chemisorbed on palladium; poorer quality spectra were obtained for both gases adsorbed on nickel. The finely divided metal samples were supported on high-area porous silica glass. The surface species derived from the initial chemisorption of acetylene on palladium and copper were found to be olefinic in type; those from ethylene on palladium were predominantly olefinic but some CH bonds of saturated groupings could also be detected. Hydrogenation of the surface species gave rise in all cases to stronger spectra of the type found with n-alkyl chains, M.(CH$_2$)$_n$.CH$_3$; for acetylene on palladium and copper n > 5, for ethylene on palladium n $\sim$ 3. The results are compared and contrasted with those obtained previously by Eischens & Pliskin (1958) for these hydrocarbons chemisorbed on silica-supported nickel.