SERVICE OF ARTILLERY

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angle for the barbette batteries," to avoid being enfiladed ortaken in reverse on the adjoining face.

PI. III. With a counter-guard before the bastion 16 or13 toises are set off from the saliant angle for the barbette,L, 3, and embrasures opened at 3, 4 of the face correspond-ing to 5 of the barbette on the bastion, when the height oflite bastion above the counter-guard is less than to feet; but■when it is 15 feet or more, the whole face of the counter-guard should be lined with cannon, in order to have twostages of fire ; as there will be no danger of the lower workbeing incommoded by the fire of the upper one. In thecounter -guard before the ravelin, the fame precaution shouldbe attended to. Guns on the faces of horn or crow re-works large enough to contain them, should be in the sameproportion.

115. The guns on the front of the attack should be ofbrass, as they stand siring for a long time : on principles ofceconomy, iron guns may be planted on the parts whence avery heavy fire cannot be kept up ; as the barbette batterieson the fronts not attacked, and the points which there isreason to apprehend the enemy may endeavour to carry byassault.

116. The most advantageous and at the fame time mosteeconomical use to which mortars can be applied in the de-fence of places, is to project stones and royal shells upon theapproaches and lodgments of the besieger. There is somuch uncertainty in the range of shells fired from largemortars against the first batteries of the besieger, notwith-standing all possible attention in the bombardiers, that theyare only employed at great distances to project shells filledwith combustibles, for discovering the progress of the be-sieger during the night, when the distance is too great forlight balls; but when the besieger approaches within thereach of light balls from the stone-mortars, the large mor-tars are then reserved for enfilading the batteries and lodge-ments on the crest of the glacis, and destroying the shaftsand slopes which the besieger has funk on the glacis and co-vered way for the attack of the countermines. Hence, anofficer aware of the manner in which the besieger can directhis attacks will necessarily conceive that two mortars of eachnature should be employed against each approach, and againsteach of the batteries in breach exposed to be enfiladed.

117. Thy