Producing Sinusoidal Waves with a Phase-Shift oscillator

Home, I say!
I wanted to play with building oscillators, so here's the implementation of a classic design for the phase-shift oscillator, using bipolar transistors. This design is based on one of the projects from Radio Shack's 300-in-1 kits. (ah, one of the many joys of my childhood)

Here's a picture of the resulting waveform, displayed on my old vacuum-tube oscilloscope. Not bad, given the utter simplicity of the circuit. By my reckoning, I think this circuit was outputting at about 155 hz. I say this because it was closest to the note D# below middle C.