268 SERVICE OF ARTILLERY
ground between the battery and the place. Too manypioneers cannot be employed in this work. during the night ;but during the day so many only as can be covered from theenemy’s fire; and to expedite the work, tire foil nearest athand is tried, s he breadth at top should be at least 4.5 seer,and the slope two thirds of the height. A berm of 5 feetis left towards the place, and the dimensions of the batteryare the fame as before directed (53 j. in the rear of thebattery a proper slope is made for the drawing up the cannon,and adjoining to it is constructed the powder magazine.
The battery for fchooi-practice on the other side of the riverPo will convey a just idea of this species of battery, and beat the fame time a convincing proof that works which re-quire so much time and labour, should never be undertakenat a siege, without an absolute necessity.
It has been advanced by some authors, that the first bat-teries should always be erected on cavaliers, even if theground be on the same plane with the place, that greaterpart of the ramparts may be thereby discovered : but if wereflect how high the cavalier must be raised before a singlefoot of the revetement can be seen, it will appear that sucha trifling advantage by no means compensates for the lossof time and labour; besides, as the first batteries are intendedto dismount the artillery of the place, and destroy the de-fences, this end will be fully answered when the besiegerfrom them can see his objects without endangering the livesof the sappers, or interrupting their progress.
55. So soon as the second parallel is completed, the firstrichochet and mortar batteries are constructed at the pointswhence the faces of the covered way, and the attackedworks can be enfiladed with most effect (17)- These bat-teries should be completed in twenty-sour hours; where-fore, 14 or 16 pioneers are allotted to every 20 feet; theparapet is faced with fascines, and the trench enlarged asmuch as may be necessary : passages of communication aremade round the rear, to prevent any embarrassment; andthe powder magazine is constructed in the space betweenthis communication and the battery. When the richochetbatteries can be incommoded by a plunging fire from thecannon of the ramparts, embrazures should be made from6 to 8 feet wide, sloping inwards : by this expedient theguns will be concealed, and may be placed closer to theparapets. When the sappers begin the third parallel, the