Spectral representation of fingerprints

PCT No. PCT/AU87/00360 Sec. 371 Date Aug. 23, 1988 Sec. 102(e) Date Aug. 23, 1988 PCT Filed Oct. 23, 1987 PCT Pub. No. WO88/03221 PCT Pub. Date May 5, 1988.An earth boring apparatus for driving a boring tool, the tool having a head for penetrating the earth and a longitudinally extending rotary drive shaft (15) for advancing the head. A carriage (18) is mounted to support frame (10) for advancing movement so as to advance and retract the drive shaft (15) and head. A drive shaft extension can be fitted between the carriage (18) and the drive shaft (15) thereby extending the effective length of the drive shaft (15). The apparatus includes a shaft engaging member (40) associated with the frame (10) and selectively operative to engage the shaft (15) having the head thereon and to inhibit rotation thereof thereby enabling the carriage (18) to be retracted and the drive shaft extension to be fitted between the carriage (18) and the shaft (15). The drive means (25) includes reaction means (30) capable of reacting to variations in earth resistance to penetration by the head, and control means (35) is responsive to the reaction means (30 ) to disable or control the operation of the advancing drive means (25) to lessen the advancing force in response to a significant increase in earth resistance. The frame (10) includes a base portion (11,14) for engaging the ground and a carriage track (20) located above the base portion (11,14) so as not to engage the ground, the carriage (18) being located laterally of the track (20) and being drivingly engaged with the track (20) from its lateral position whereby reducing debris causes interference with the drive engagement between carriage (18) and the track (20).