The Germans do not name their shells from the diameter of the bore which receives them, but from the weight of a stone ball that fits the same bore as the shell. Thus a 7 lbs. howitzer admits a stone ball of that weight; the shell for this weighs 15 lbs. and answers to the English 5½ inch. The 30 lbs. howitzer shell weighs 60 lbs. and is rather more than 8 inches in diameter. NOTE.—Shells were till lately made thicker at the bottom than at the fuze hole; but are now cast of the same thickness throughout, and are found to burst into a greater number of pieces in consequence. _SHOT._—_Rules for finding the Number in any Pile._ _Triangular Pile._ Multiply the base by the base + 1, this product by the base + 2, and divide by 6. _Square Pile._ Multiply the bottom row by the bottom row + 1, and this product by twice the bottom row + 2, and divide by 6. _Rectangular Piles._ Multiply the breadth of the base by itself + 1, and this product by 3 times the difference between the length and breadth of the base, added to twice the breadth + 1 and divide by 6. _Incomplete Piles._ Incomplete piles being only frustrums, wanting a similar small pile on the top, compute first the whole pile as if complete, and also the small pile wanting at top; and then subtract the one number from the other. _Rules for finding the Dimensions and Weight of Shot._ The weight and dimensions of shot or shells might be found by means of their specific gravities; (see the word _Gravity_;) but they may be found still easier, by means of the experimented weight of a ball of a given size, from the known proportion of similar figures, namely as the cubes of their diameters. 1st. _To find the Weight of an Iron Ball from its Diameter_—An iron ball of 4 inches diameter weighs 9 lbs. and the weights being as the cubes of their diameters, it will be as 64, (the cube of 4,) is to 9, so is the cube of the diameter of any other ball to its weight. 2d, _To find the Weight of a Leaden Ball_.—A leaden ball of 4¼ inches diameter weighs 17 lbs. Therefore, as the cube of 4¼ is to 17, (as 9 to 2 nearly,) so is the cube of the diameter of any leaden ball to its weight. 3d, _To find the Diameter of an Iron Ball_.—Multiply the weight by 7¹/₉ and the cube root of the product will be the diameter. 4th, _To find the Diameter of a Leaden Ball_.—Multiply the weight by 9, and divide the product by 2; and take the cube root of the quotient for the diameter. _Table of Diameters of English Iron Round Shot._ +-------+---+-----+-----+-----+-----+-----+-----+-----+-----+----+ |Nature.| 68| 42 | 32 | 24 | 18 | 12 | 9 | 6 | 3 | 1 | +-------+---+-----+-----+-----+-----+-----+-----+-----+-----+----+ |Inches.| 8.|6.684|6.105|5.547|5.040|4.403|4.000|3.498|2.775|1.92| +-------+---+-----+-----+-----+-----+-----+-----+-----+-----+----+ _Diameters of French Iron Round Shot in English Inches._