Spin resonances can depolarize or spin-flip a polarized beam. We studied 1st and higher order spin resonances with stored 2.1 GeV/c vertically polarized protons. The 1st order vertical ({ u}y) resonance caused almost full spin-flip, while some higher
order { u}y resonances caused partial depolarization. The 1st order horizontal ({ u}x) resonance caused almost full depolarization, while some higher order { u}x resonances again caused partial depolarization. Moreover, a 2nd order { u}x resonance is about as strong as some 3rd order { u}x resonances, while some 3rd order { u}y resonances are much stronger than a 2nd order { u}y resonance. One thought that { u}y spin resonances are far stronger than { u}x, and that lower order resonances are stronger than higher order; the data do not support this.
