opposite the high main. From his examination, they had failed under tension (and therefore, he deduced, before the beam broke). John Hosking gave expert evidence on the pump beam. He pointed to weakness in the beam design and its installation. There was too much metal in the central boss and in ribs, whose net effect was to weaken the beam. The orientation of the hexagonal holes (apexes at dead top and dead bottom) had both weakened the beam and given points from which a fracture could start. The beam had been secured on the gudgeon by driving wedges between them; from the hammer marks on the wedges, this seemed to have been done with excessive force, which would have introduced undesirably high local stress. It would have been better ('modern practice') to machine the central boss holes and the middle portion of the 'gudgeon' circular, with better engineered keying between beam and 'gudgeon'. An ironfounder considered the iron of good quality; its strength was demonstrated by the irregularity of the fracture surface, and its quality by the colour of the fracture surface when fresh. There was no undue contraction. Hosking did not think a pump piston had wedged, the bottom spear had broken under normal load: "The wood does not appear to me to have been of very good quality. It might have been at one time, but is not now." He dismissed as irrelevant two points which had attracted comment: considerable voids ( x ) could be seen at the fracture surface close to the central boss; they were shrinkage voids, to be expected with so massive a casting unless special precautions were taken, and would not significantly affect the strength of the beam. he did not think that the earlier drop had any connection with the subsequent failure: the beam had fallen only which he thought insufficient to initiate any fracture; the drop had occurred 33 days before the beam failed – he did not think a significantly damaged beam would have survived so long; the fracture surface after the beam failure had been uniformly bright, which ruled out any slow progressive failure or partial previous failure. Blackwell's report to Grey (written a week after the inquest) concurred with Hosking and drew attention to factors which Blackwell felt had made the accident more likely than for most pumping engines; at Hartley both 'inhouse up' and 'inhouse down' strokes