Show COAS HOW T is upon the seaboard guns that the security of the nation will depend should an enemy succeed in crippling our far flung line the navy and drive our ta to the cover ot the harbors and the protection of the heavy aldea and mortars ot the army the question Is can these seaboard batteries hold a foe at bay on our continental shores we have a total of 26 coast defense commands and 21 of these are located upon the atlantic littoral but even though there are fewer stations on the pa coast still those are very formidable with out considering weapons of eight inch caliber and under we already have mounted a total upon our two shores of 12 inch mortars 12 inch rifles and 10 inch heavy guns the strength of the personnel of the coast artillery according to the latest figures Is officers and enlisted men this Is a shortage of sol adlers of 1420 agreeably to the force authorized by law and this Is an intimation of the extremely heavy work that the men would have to face in case of hostilities because we are minus a vitally necessary reserve the average layman has but the slightest knowledge of the extremely technical character of the coast artillery corps and to be proficient these soldiers receive a many sided education theirs Is the task of getting the advantage of the enemy before the foe can locate the position of our guns and mortars and the whole system of defense Is the exact opposite of the way in which a hostile squadron would approach its ag gresslee gress lve task from the very beginning of the planning of our existing seaboard batteries the idea of conceal ment was the first concern the mortars were designed to be hidden away in pits each of them holding four of these weapons the heavy rifles were not to be in plain sight with their threatening muzzles peering over the crests of parapets instead the disappearing carriage was invented for a mount these gave the rifles the power to crouch while loading or awaiting ice and then when the moment for action ar rived to spring up suddenly from behind their embrasures embra to fire directly at the toe and by the force of their own recoil to sink from view and into position for reloading how Is it possible for weapons of this sort to be aimed at their targets it la commonly known that in naval service the guns are held upon their quarry by means of electrically operated mechanisms that swing and elevate the rifles so that the cross hairs of the telescopic can be kept right on a moving target even though the sea be rough and the vessel roll the gun pointers are undisturbed by this motion and at 12 yards and more are able to do some won darful shooting dut the gun pointers and train era in the mortar pits and the em placements ot the big rifles do not themselves see the enemy yet despite this seeming handicap still they are able to do some extraordinarily effective work the army gun pointers near new york with 10 inch disappearing rifles have been able to alro four shots in a total elapsed time of less than one minute and these were concentrated upon a target four miles away being towed at the rate of something over five miles an hour all tour shots struck tho target and actually passed through a rectangle 24 feet high by 63 feet long at 4 yards the same caliber guns at fortress monroe scored six hits out of six shots at a moving target the total elapsed time of the firing was slightly over two minutes the batteries scoring 1 4 hits per gun per minute the science of surveying has made these achievements possible even though as had been said the guns and mortars must be trained and elevated by men who cannot see their targets it Is a well known theorem in plane geometry that the length of the two sides of a triangle may bo found if the length of the base and the degree of the two angles formed by the sides in question with this base are known in the case of taft coast artillery problem the distant ship 0 the foe la at the remote tip of the imaginary triangle and the known base is the span between two observing or range finding stations this interval may be a mile or more and within some limits the longer the better for accuracy many have seen from afar at our coast defense stations what seemed to be big bird boxes mounted upon towering tubular supports or of steel there are always two of them and officially they are known as the primary and secondary range stations in each of them in time of service there are at least two men one turns by means of a delicately graduated mechanism a powerful telescope from right to left and his function Is to keep the moving tar get continually at the point of intersection ol 01 two cross hairs in the field of bis instrument ills companion reads oft at prescribed intervals the angle made by the telescope with the per manent base and the faraway foe the same thing Is being done at the other range station at the opposite end of the base A time bell rings at each of these stations every 20 seconds and at the third stroke the man read ing the angular scale telephones that measurement to the plotting room located where the enemy cannot see it and itself in telephonic communication with each gun or mortar division in the plotting room a group of men make use of the information coming to them intermittently from the range finding towers and by a graphic process determine with great nicety the distance off of the steaming foe the plotting table or board where the information from the observers Is applied Is a big semicircular affair the curved edge being graduated to tr actions of a degree while the straight edge or diameter represents on a definite scale the length of the base line between the two spotter towers at each end of this base line Is a pivoted ruler one Is called the primary and the other the secondary corresponding sp to the range finding station with which its operator Is in touch by telephone here Is what follows the soldiers at the primary and secondary pivoted rulers or arms bring the free ends toward one another in accordance with the separate angles telephoned to them A third man operates another ruler called the gun arm which measures the distance or range of abo axis of this triangle at the word of command from the range officer the observers at the two telescopes bring these powerful instruments to bear in unison upon a chosen part of the remote ship at the order take the scale readers telephone the figures to the operators at the plotting board in a few seconds the man in charge there has placed on a large sheet of paper a dot at the point where the two straight edges meet and has marked this pencilled point no 1 again 20 seconds later another dot la made where the shit ting straight edges meet and this is numbered 2 similarly positions are thus recorded tor no 3 and no 4 and if the distance between these dots is uniform the plotters know that the target Is moving at a steady speed and the path dots gives a visible trace of the durec f A alon in which the toe la As yd none 0 the weapons has been pointed nor it mortars are to be used even been loaded the plotters marks upon his paper a fifth point ahead and in line the four other dots this Is his predicted point where the enemy vessel should be a minute later in this interval ot time it Is necessary for the men in the plotting room to do a number of things necessary to make it possible for the weapons to score a hit the mere range Is not enough to know let us as sume that the foe Is to be attacked by means of mortara and that the projectiles are to soar thousands of feet into the air upon their long night that may take the better part of to minutes before plunging upon the vulnerable decks of the hostile dreadnought it Is needful to know how long the shells will be in the air at that range how far the target will move during the flight of the missiles how much the path of the projectiles will be influx encee by drift due to their own rotation and the effect of the prevailing wind the exact powder charge that will be needed to propel the shells this being determined by the range and the state of the atmosphere and finally how much ahead the mortars must be aimed in order to allow for these factors these complications are due to the method of indirect alre employed and in this particular the mortars are not so accurate as the big rifles and therefore are more difficult to handle in order to insure good results the final point set in the plotting room Is no 6 and two minutes further along than no 6 the predicted point the latter being verified by the angles given by the observers at the spotter stations when the vessel Is duly reported at the proper moment all of this has taken longer to describe than actual performance calls for because the error factors which have been just mentioned are tabu and are quickly worked out graphically by means of cunningly devised apparatus it must be evident that in an interval of tour minutes a big ship 12 or 16 yards off would not get measurably closer and once the proper range Is found and the mortars loaded the shifting range Is quickly verified and the guns set accordingly the men in the towers and those in the plot ting room are at work all the while at definite intervals the instructions are sent by telephone from the plotting room to each battery or mortar pit and lest these vocal directions be ml sunder stood the figures and orders are visibly reproduced for this work the Is em aloyed and thus words and numbers in writing check the telephone calls As has been said there are four mortars in each pit and as a gendral thing there are four of these pits at each defense station in other words a salvo of 16 high explosive shells can be launched by indirect fire at a foe it but two of these hit the enemy she would either bo destroyed or gravely damaged because none of her decks would be able to withstand such an assault in practice the performances of such a battery have been splendid As a matter of record one mortar company has fired as many as ten shot in 6 minutes 49 seconds and in that in berval made six bits while another company has scored eight times out of ten shots during a span of 9 minutes 28 seconds these mortar projectiles weigh from to 1 pounds and are charged with from 30 to 60 pounds of high explosive for the disappearing guns the modus operands ope randl differs in some particulars the time of flight of the shot Is far shorter than in the case of tha mortar shell the powder charge Is not varied to suit different ranges and the state of the atmosphere Is not a deciding factor therefore corrections ions are more easily made tor the rifle when it does fire Is pointed right at its target the principal concern of the battery commander Is to know the range and this Is telephoned and reproduced by the at tha firing sta alons the battery commander also follows the enemy ship with a telescopic range finder that employs a short vertical instead of a horizontal base this serves as a check and at each gun there Is a tele sight which Is functioned independent 0 the weapon the operator looking over the para pet and following continually the moving quarry by swinging bis telescope horizontally he causes the lateral angle to be indicated at the gun sta alon below and there the trainer swings the weapon in unison and the elevator raises the muzzle agreeably to instructions from the range binders when the rifles have been loaded and the moment for action arrives these great war dogs rise upon their steel haunches and thrust their muzzles above the heavy parapets of concrete instantly there Is a thunderous boom the speeding projectiles are on their murde roi mission before the thin veil of smoke has been swept aside the guns have sunk behind cover and but for the momentary flashing of their muzzles there Is nothing to show the spotters on the hostile craft where the attacking guns lie |