sentences:  They also confirmed that the ink contained only trace amounts of iron, and that the black line remnants were on top of the yellow, indicating that they were not the remains of a penciled guide-line, as the British Museum staff had speculated.A new investigation in the early 1980s, by a team under Dr. Thomas Cahill at the University of California, Davis, using Particle-Induced X-ray Emission (PIXE) found that only trace amounts (
  
   which should have been too little for some of McCrone's analyses to detect.The Cahill team acknowledged, however, that titanium was the only element within their technique's measurement capability which was significantly more concentrated in the ink than on the bare parchment (other elements such as iron and zinc were found concentrated in some inked samples, but only a minority).