OCR Text |
Show .VI I note Screw. It la asserted that the smallest screws known are those used in the production of watches Thus, the fourth jewel wheel screw comes very near being in visible to the naked eye, looking. hen viewed by a person of ordinary gift of evesight. like n small speck of dust With a glass it is seen to be a small but erfect screw, with threads so tine that it would take 2U of theiu to wind around the littlo speck of wire to the i distance of half an inch. These minute mechanical atoms are but the forty-one thousandth of an inch in diameter mid less than the ten-thousandth of an inch in length. A lady's thimble of tlie or ! dinary tie. say n No. 7. would hold 10U.IW0 of these little but useful specks of brass. SL Ixniis Republic. |