11. IN APPARATUS FOR RECORDING ON A RECORD RECEIVING MEMBER THE RATE OF PENETRATION IN A BORE HOLE OF A DRILL BIT SECURED TO A DRILL STRING: FIRST MEANS ADAPTED TO RECEIVE THE RECORD RECEIVING MEMBER AND ADAPTED FOR MOVEMENT IN PROPORTION TO MOVEMENT OF THE DRILL STRRING AND BIT TO CORRESPONDINGLY MOVE THE RECORD RECEIVING MEMBER; A MOVABLE CARRIAGE; A MARKER ON SAID CARRIAGE ENGAGEABLE WITH THE RECORD RECEIVING MEMBER; FLUID ACTUATED MEANS ENGAGEABLE WITH SAID CARRAIGE FOR MOVING SAID CARRIAGE AND MARKER WITH RESPECT TO SAID FIRST MEANS AND RECORD RECEIVING MEMBER IN DIRECTION TRANSVERSE TO THE DIRECTION OF A MOVEMENT OF SAID REORD RECEIVING MEMBER; SECOND MEANS FOR ADMITTING FLUID UNDER AN AUTOMATICALLY CONTROLLED CONSTANT PRESSURE TO SAID FLUID ACTUATABLE MEANS AT A PREDETERMINED RATE TO EFFECT MOVEMENT OF SAID FLUID ACTUATED MEANS AT A CONSTANT PREDETERMINED RATE FROM AN INITIAL POSITION AND DETERMINE THE POSITION OF SAID CARRIAGE AND MARKER; THIRD MEANS OPERATIVELY CONNECTED TO SAID SECOND MEANS FOR CONTROLLING PASSAGE OF FLUID UNDER PRESSURE THERETO; AND MEANS OPERATIVELY CONNECTING THE