This chapter reports our SR measurements of the spin-ladder
cuprates Srn-1Cun+1O2n (n=3, 5). The measurements have revealed
contrasting magnetic behaviors between the `2-leg' (n=3)
and the `3-leg' (n=5) spin-ladder materials, which qualitatively
agree with the theoretical predictions. The results
presented in this chapter, in addition, provide a good example of how
SR
detects the existence/absence of magnetic order.