326 SERVICE OF ARTILLERY

lance, and a mine sprung to destroy his works (147). EtJtif he advance on a permanent branch at a distance from theprovisional ones, the nearest provisional branch ought to becarried forward to meet him as before directed.

152. It may happen either through the negligence of thebesieged, from the nature of the ground, or the instrumentsused in boring it, that the besieger may without being heardgain the wall of the countermines: in this cafe, a largepetard well propped behind should be instantly fixed againstthe part he is approaching, and the screws that fasten it tothe plank taken out, that it may act against the wall withgreater force and do the enemy more damage : as soon afterthe explosion as the smoke will permit, the miners shouldexamine if any communication be opened between the coun-termine and the enemy’s works ; throw in quantities of fetidcombustibles; close the hole hermetically, to prevent the stenchfrom pasting into the countermines; and block up at thesame time all access to the besieger.

Should the besieger gain an entrance into any of the coun-termines, some of the most resolute miners armed with cui-rasses and blutiderbusies should be sent to drive them as farback as possible, and the communication be interrupted andblocked up with sand-bags; all forts of combustibles should bethrown into the intercepted part to compel the enemy toabandon it.

153. The garrison should never relax in opposing the designsof the enemy, even though all the permanent counterminesare by degrees destroyed and they are thus deprived of themeans of blowing up the enemy’s batteries; since the de-fence of the place will be thereby considerably protracted:Whereas should they under the idea of preserving the perma-nent works entire, be too cautious in counteracting the be-sieger, he may by carrying on his enterprises under ground,render all the countermines useless; and deprive the garrisonof every benefit that could result from them.

After springing a mine, the miners should never be toohasty in removing the earth or rubbish that chokes up thepassage to it, or in examining its effects ; this research beingattended with no utility, and moreover, very dangerous:the smell and smoke should be drawn away, and the air pu-rified by placing mantlets at the entrance into the counter-mines, with tin pipes fixed in them and communicating withthe place where the mine was sprung. The miners in the.

mean