The Artizan . lineof direction of its motion is essential to accuracy of firing, 2nd. The charge of rifled, which is smaller than that of smooth arms,may be varied only in very narrow limits. 3rd. The length of the bore should be less in rifled than in smooth arms. 4th. The obliquity of the grooves may vary considerably without affect-ing the accuracy of the firing. 5th. The accuracy varies to a certain extent in inverse ratio with thenumber of grooves. Some imporant results were also arrived at with reference to the flat andspherical balls:— 1st. They should be made to revolve round their min
The Artizan . lineof direction of its motion is essential to accuracy of firing, 2nd. The charge of rifled, which is smaller than that of smooth arms,may be varied only in very narrow limits. 3rd. The length of the bore should be less in rifled than in smooth arms. 4th. The obliquity of the grooves may vary considerably without affect-ing the accuracy of the firing. 5th. The accuracy varies to a certain extent in inverse ratio with thenumber of grooves. Some imporant results were also arrived at with reference to the flat andspherical balls:— 1st. They should be made to revolve round their minor axes, being thoseof the greatest momentum of inertia. 2nd. For such balls the less obliquity of the grooves is preferable. Rifled arms with chambers were subject to the drawback of requiringspecial cartridges, difficult to make, and easily damaged, whereforeThouvenin and Minies system was adopted, with the form of ball shownfull size iu Fig. 1 (1844). In 1845 and 1846 experiments were undertaken Fie . to determine the best form of grooves. It was found that guns rifledfrom right to left produced deviation to the left, and vice versa. A pitchof 5-56ft. received preference. The grooves were helicoidal, and turnedfrom left to right, wide and shallow, with sharp corners, and the bottomconcentric with the Bides of the arm. The grooves were four in number,SnUfiS?1 equal to one-eSnth the interior of the periphery, with a depth of•01968m., or -5 millimetres.* An investigation into the influence of the new form on the progress ofthe projectile resulted in the following conclusions — 1st. The rotatory speed of the projectile should increase in direct ratio lenth a °f the heUx Sh°Uld Vary inversely with this „3fl\The Cha,,?° #5°&ra£ 254 drams) is small«- than that forunnflcd arms, further, M. Tamisier found that the stability of the axis =*0-O3937in11UShatiOn3 ^ dimcnsions ave marked ™ millimetres. 1 millimetre of rotation for lengthened projectiles depends on
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Keywords: ., bookcentury1800, bookdecade1840, booksubje, booksubjecttechnology
