I
>
I
i
FIRED GUN-POWDER. YZ
the guns were laid with every necessary precaution. Themedium of several rounds was taken, and the direction wasalong that part of the Po, which runs almost in a right linefrom the mills of Rocca-Franca to the Chapel of the Crucifix.
Comparison between the actual ranges of shot measured inJune 1764, along the Banks of the Po, and those which agiven initial velocity would produce, if there were no resistancein the air to the motion of the (hot.
Vclo.
Eleva-
tion.
Ranges.
'—f
Experi- Poteo-mented. rial.
Rifled Carabines bullets weighing£ of an ounce.
Wall*
•pieces. «
Balls weighing 3 \
oz. 1
Balls weighing 3 s
i oz *. . 1
Balls weighing 3oz. but eqiin diametrr3} oz. balls.
’g 3 r
qual 1r to 1
5 I
Feet.
1956
Mufquet, weight of bullet 1 oz. J 1736
i
1855
> 77 °
*o68
* 5 *
240
45 °
7 °
-5°
- 4 °
45 °
- 3 °
- 4 °
45 °
20"
20"
> 5 9
Yds.
901
938
895
948
>305
>333
1181
>433
>733
>629
>699
Yds.
19903
29854
39806
7845
15691
-3337
3-38z
>7897
26734
35794
>6307
- 3 "
>630
2226S
U V. B. During the five mornings that these experimentswere carrying op, the barometer at the battery wasstationary at 29 inches, except towards the end of thethird morning when it rose a little.
This comparison shews that the rifled carabine with an ini-tial velocity of 1956 feet only ranged 895 yards, at the ele-vation of 45 0 ; while that from the theory of projectilesmoving in vacuo, it should have ranged 39806. Now asthe only difference between the range calculated from theinitial velocity , measured near the mouth of the piece, and theactual range at the elevation of 45°, is in the space passedthrough by the sliot; it must be, owing to the mass of airdisplaced by it, and consequently to the resistance that the airopposes to its motion.
187. The
i