SO SELECT EXERCISES.

and hold the cube by the pin, whichv may be called its axis, and keep oneof its fides toward any fide of theroom. Whilst you do this, you donot turn the cube round its axis, whe-ther you still keep it in the fame place,or carry it round any other fixed bodyon the table.—But if you try to keepany side of the cube toward the fixedbody, whilst you are carrying it roundthe fame, you will find that you can-not do so, without turning the pintround (which is fixed into the cube)betwixt the finger and thumb wherebyyou hold it; unless you rife and walkround the table, keeping your facealways toward the fixed body on thetable; and then, both yourself and thecube will have turned once round;for the cube will have shewn the sameside progressively round to all sides ofthe room, and your face will havebeen turned toward every side of theroom, and every fixed point of thehorizon.

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