=To Break or Stop the Signals from the Sending Station.=--Signal "A" without pause until acknowledged. =To Start the Sending Station after Breaking.=--Signal "G A " followed by "front" and the last word correctly received; the sender will immediately resume his message, beginning with the word indicated by the receiver. If nothing has been received, signal "R R"; the sender will then repeat all. =Error in Sending.=--Signal seven dots (·······) rapidly followed by "front," and resume the message, beginning with the last word correctly sent. =End of Address.=--Signal the period (··--··) followed by "front." =Signature Follows.=--Signal "Sig" followed by "front." =To Acknowledge Receipt of a Message.=--Signal "O K" followed by "front" and personal signal or initial of receiver. PENETRATION OF PROJECTILES. Experiments at Lydd, in 1886, showed that earthen parapets of sandy loam 12 feet thick were but little affected by the fire from B. L. 12-pdr. and 20-pdr. with steel shells, and the following rough rules will probably suffice against field-guns: For friable soil, such as sand, etc. 2 yards For medium soil, such as ordinary earth 2½ yards For tenacious soil, such as clay 3 yards The following data, obtained from experiments by the Germans, may prove of service: PENETRATION FROM ARTILLERY-FIRE. --------------------------------------------+---------------------- Field-artillery. |Garrison and Siege | Artillery. --------------------------------------------+---------------------- Shrapnel; {bullets } in earth, 16 to 39 in.|In earth 39 in. {fragments} | | Shrapnel, wood, overhead cover 2 in. | Wood, } |overhead cover } 4 in. | Individual shot: | Striking fair, earth 39 to 79 in. |Earth 10 to 13 ft. Striking fair, brickwork 39 in. | Striking fair, snow about 27 ft. | --------------------------------------------+---------------------- PENETRATION FROM INFANTRY-FIRE. Sand 29½ in. Rammed snow 6 ft. 9 in. Sheaves of grain 16 ft. 9 in. Pine 39 in. Steel plate 0.8 in. Ordinary earth 39 in. Swampy or wet ground 79 in. Laid sods and turf 79 in. Oak 24 in. Brickwork 19½ in. A double thickness of planks filled in with broken stone 7.8 in.