it was thus with interest that leavitt and burton looked over the computer printout , a column of figures written on green paper : mass spectrometry data output print percentage output sample 1 - black object unidentified origin [ diagram of chemistry of the rock from h to br ] all heavier metals show zero content sample 2 - green object unidentified origin [ diagram of chemistry of green object ] all heavier metals show zero content end print end program -stop- what all this meant was simple enough .