Q. A. Gillmore to To the ADJUTANT-GENERAL U. S. ARMY, April 9, 1869

April 9, 1869.

No. 17. Tybee Island, Ga., April 9, 1869.

The batteries established against Fort Pulaski will be manned and ready for service at break of day to-morrow. The signal to begin the action will be one gun from the right mortar of Battery Halleck (2,400 yards from the work), fired under the direction of Lieut. Horace Porter, chief of ordnance. Charge of mortar, 11 pounds; charge of shell, 11 pounds; elevation, 55 degrees; length of fuse, 24 seconds. This battery (two 13-inch mortars) will continue firing at the rate of fifteen minutes to each mortar alternately, varying the charge of mortars and the length of fuse so that the shells will drop over the arches of the north and northeast faces of the work and explode immediately after striking, and not before.

The other batteries will open as follows, viz, Battery Stanton (three 13-inch mortars, 3,400 yards distant) immediately after the signal, at the rate of fifteen minutes for each piece, alternating from the right. Charge of mortars, 14 pounds; charge of shell, 7 pounds; elevation, 45 degrees; length of fuse, 23 seconds; varying the charge of mortar and length of fuse as may be required. The shells should drop over the arches of the south face of the work and explode immediately after striking, but not before.

Battery Grant (three 13-inch mortars, 3,200 yards distant) immediately after the ranges of Battery Stanton have been determined, at the rate of fifteen minutes for each piece, alternating from the right. Charge of shells, 7 pounds; elevation, 45 degrees; charges of mortars and length of fuse to be varied to suit the range, as determined from Battery Stanton. The shells should drop over the south face of the work and explode immediately after striking, but not before.

Battery Lyon (three 10-inch columbiads, 3,100 yards distant), with a curved fire, immediately after the signal, allowing ten minutes between the discharges for each piece, alternating from theright. Charge of gun, 17 pounds; charge of shell, 3 pounds; elevation, 20 degrees, and length of fuse, 20 seconds; charge and length of fuse to vary as required. The shells should pass over the parapet into the work, taking the gorge ms north face in reverse, and exploding at the moment of striking or immediately after.

Battery Lincoln (three 8-inch columbiads, 3,045 yards distant), with a curved fire, immediately after the digna allowing six minutes between discharges for each piece, alternating from the right. Charge of gun, 10 pounds; charge of shell, 13 pounds; elevation, 20 degrees, and length of fuse, 20 seconds. Directed the same as Battery Lyon ope the gorge and north face in reverse, varying the charge and length of fuse accordingly.

Battery Burnside (one 13-inch mortar, 2,750 yards distant) firing every ten minutes » from the time the range is obtained for Battery Sherman. Charge of shell, 7 pounds; elevation, 45 degrees ; charge of mortar and length of fuse varying as required from those obtained for Battery Sherman. The shells should drop on the arches of the north and northeast faces, and explode immediately after striking, but not before.

Battery Sherman (three 13-inch mortars, 2,650 yards distant) commencing immediately after the ranges for Battery Grant have been determined, and firing at the rate of fifteen minutes for each piece, alternating from the right. Charge of shell, 7 pounds elevation, 45 depress: charge of mortar and length of fuse to be fixed to suit the range, as determined from Buttery Grant. The shells should drop over the arches of the north and northeast faces.

Battery Scott (three 10-inch and one 8-inch columbiads, 1,740 yards distant) firing solid shot, and commencing immediately after the barbette fire of the work has ceased. Charge of 10-inch columbiads, 20 pounds; elevation, 44 degrees. Charge of 8-inch columbiad, 10 pounds; elevation, 5 degrees. This battery should breach the pancoupé between the south and southeast faces, and the embrasure next to it, in the southeast face, the elevation to be varied accordingly; the charge to remain the same. Until the elevation is accurately determined each gun should fire once in ten minutes; after that every six or eight minutes.

Battery Sigel (five 30-pounder Parrotts and one 48-pounder James, old 24-pounder rifled, 1,670 yards distant) to open with 43-seconds fuses on the barbette guns of the fort at the second discharge from Battery Sherman. Charge for 30-pounder, 3} pounds; charge for 45-pounder, 5 pounds; elevation, 4 degrees for both calibers. As soon as the barbette fire of the work has been silenced this battery will be directed with percussion shells upon the walls, to breach the pan-coupé between the south and southeast faces, the elevation to be varied accordingly, the charge to remain the same. Until the elevation is accurately determined each gun should fire once in six or eight minutes; after that every four or five minutes.

Battery McClellan (two 84 and two 64-pounders James, old 42 and 32 pounders rifled, 1,650 yards distant) opens fire immediately after Battery Scott. Charge for 84-pounder, 8 pounds; charge for 64-pounder, 6 pounds; elevation for 84-pounder, 4} degrees, an for the 64-pounder, 4 degrees. Each piece should fire once every five or six minutes after the elevation has been established. Charge to remain the same. This battery should breach the work in the pan-coupé between the south and southeast faces and the embrasure next to it in the southeast face. The steel scraper for the grooves should be used after every fifth or sixth discharge.

Battery Totten (four 10-inch siege mortars, 1,650 yards distant) opens fire immediately after Battery Sigel, firing each piece about once in five minutes. Charge of mortar, 34 fuse, 184 seconds. The charge of mortar and length of fuse to vary so as to explode the shells over the northeast and southeast faces of the work. If any battery should be unmasked outside the work, Battery Totten will direct its fire upon it, TeDe the charge and length of fuse accordingly. The fire from each battery will cease at dark, axcept especial directions be given to the contrary. A signal officer at Battery Scott, to observe the effect of the 13-inch shells, will be in communication with other signal officers stationed near Batteries Stanton, Grant, and Sherman, in order to determine the range for these batteries in succession.

By order of Brig. Gen. Q. A. Gillmore:

First Lieutenant, Volunteer Engineers, and Actg. Asst. Adjt. Gen.

Just after sunrise, on the morning of the 10th, Maj. Gen. David Hunter, commanding the department, dispatehed Lieut. J. H. Wilson, of the Topographieal Engineers, to Fort Pulaski, bearing a flag of truce and a summons to surrender. To this demand a negative answer was returned. :

The order was given to open fire, commencing with the mortar batteries, agreeably to the foregoing instructions.

The first shell was fired at a quarter past 8 o’clock a. m. from Battery Halleck. The other mortar batteries opened one after the other, as rapidly in succession as it was found practicable to determine the approximate ranges by the use of signals. The guns and columbiads soon followed, so that before half past 9 a. m. all the batteries were in operation, it having been deemed expedient not to wait for the barbette fire of the work to be silenced before opening with Breaching Batteries Scott and McClellan. /

The three 10-inch columbiads in Battery Scott vere dismounted by their own recoil at the first discharge, and one of those in Battery Lyon, from the same cause, at the third discharge. The gun-carriages were the new iron pattern, while the pintles and _pintle-crosses belonged to the old wooden carriages, and were unsuitable. They were all, except one in Battery Scott, subsequently remounted and served. pond

As the several batteries along our line, which was 2,550 yards in

pounds; charge of shell, 3 pounds; elevation, 45 degrees, and length of

length, opened fire one after another, the enemy followed them up successively with a vigorous though not at first very accurate fire from his barbette and casemate guns. Subsequent inquiry showed that he knew the exact position of only two of our batteries—Sherman and Burnside. These were established just above bigh-water mark, on low ground, void of bushes or undergrowth of any kind. During their construction no special attempt at concealment had been made after once securing good parapet cover by night work. i

Great surprise and disappointment were expressed by all experienced officers present at the unsatisfactory results obtained with the 13-inch mortars. Although the platforms were excellent and remained for all useful purposes intact, and although the pieces were served with a fair degree of care and skill, not one-tenth of the shells thrown appeared to fall within the work—an estimate that was afterwards found to be rather over than under the correct proportion. Whether this inaccuracy is due to the fact that no cartridge-bags were furnished for the mortars, to inequalities in the strength of the powder, to defects inherent in the piece itself, or to these several causes combined, remains yet to be ascertained. It is suggested-that the earnest attention of the proper department be directed to this subject.

By 1 o’clock in the afternoon (April 10) it became evident that the work would be breached, provided our breaching batteries did not become seriously disabled by the enemy’s fire. By the aid of a powerful telescope it could be observed that the rifled projectiles were doing excellent service, that their penetration was deep and effective, and that the portion of the wall where the breach had been ordered was becoming rapidly honey-combed.

It also became evident before night, on account of the inefficiency of the mortar firing, that upon breaching alone ending perhaps in an assault, we must depend for the reduction of the work.

In order to increase the security of our advanced batteries a tolerably brisk fire against the barbette guns of the fort was kept up throughout the day. Probably from 15 to 20 per cent. of the metal thrown from the breaching batteries on the 10th was expended in this way.

As evening closed in, rendering objects indistinct, all the pieces ceased firing, with the exception of two 13-inch mortars, one 10-inch mortar, and one 30-pounder Parrott, which were served throughout the night at intervals of fifteen or twenty minutes for each piece. The object of this was to prevent repairs of the breach or the filling of the casemates in rear of it with sand bags or other material.

I extract as follows from my preliminary report to Brigadier-General Benham, dated April 12, 1862:

The only plainly perceptible result of this cannonade of ten and a half hours’ duration (on the 10th), the breaching batteries having been served but nine and a halt hours, was the commencement of a breach in the easterly half of the pan-coupé connecting the south and southeast faces, and in that portion of the southeast face spanned by the two casemates adjacent to the pan-coupé.

The breach had been ordered in this portion of the scarp so as to take in reverse, through the opening formed, the powder magazine, located in the angle formed by the gorge and the north face.

ENDE the barbette guns of the fort had been disabled and three casemate guns silenced.

The enemy served both tiers of guns briskly throughout the day, but without injury to the matériel or personnel of our batteries.

On the morning of the 11th, a little after sunrise, our batteries again opened fire with decided effect, the fort returning a heavy and welldirected fire from its casemates and barbette guns. The breach was rapidly enlarged. After the expiration of three hours the entire case mate next the pan-coupé had been opened, and by 12 o’clock the one adjacent to it was in a similar condition.

Direetions were then given to train the guns upon the third embrasure, upon which the breaching batteries were operating with effect, when the fort hoisted the white flag. This occurred at 2 o’clock.

The formalities of visiting the fort, receiving its surrender, and occu pying it with our troops, consumed the balance of the afternoon and evening.

During the lith about one-tenth of the projectiles from the three breaching batteries were directed against the barbette guns of the fort. Eleven of its guns were dismounted, or otherwise rendered temporarily unserviceable.

The garrison of the fort was found to consist of 385 men, including a full complement of officers. Several of them were severely, and one fatally, wounded.

Our total loss was 1 man killed. None of our pieces were struck.

I take pleasure in recording my acknowledgment of the hearty, zealous, and persevering co-operation afforded me by the officers and men under my command, not only during the 10th and ilth, when all more or less forgot their fatigue in the excitement and danger of the engagement, but throughout the exhausting and unwholesome labors of preparation, occupying day and night a period of nearly eight weeks.

The entire available strength of the command was on guard or fatigue duty every twenty-four hours.

The details for night work were always paraded immediately after sunset, and were usually dismissed from labor between 1 and 2 o’clock in the morning, although circumstances frequently required parties to remain out all night.

In unloading the ordnance and ordnance stores advantage was always taken of favorable tide and weather day and night.

There is one circumstance connected with this siege which appears to deserve special mention, and that is, that with the exception of a detachment of sailors from the frigate Wabash, who served four of the light siege pieces in Battery Sigel on the 11th, we had no artillerists of any experience whatever. Four of the batteries were manned by the Third Rhode Island Volunteer Artillery, who were conversant with the manual of the pieces, but had never been practiced at firing. Al the other pieces were served by infantry troops, who had been on constant fatigue duty, and who received all their instruetions in gunnery at such odd times as they could be spared from other duties during the week or ten days preceding the action.

Instructions had been given by General Benham to place a mortar battery on the lower end of Long Island and two 10-inch columbiads on Turtle Island, in order to obtain a reverse fire ou the work. These batteries were to have been erected and manned by detachments from General Viele’s command. One 10-inch siege mortar was therefore placed on Long Island, and was served on the 11th April by a detachment commanded by Major Beard, Forty-eighth New York Volunteers. It was entirely ineffective on account of the distance—nearly 1,900 yards. The idea of Turtle Island battery was not carried into effect, and no pieces were landed there. i

Throughout the siege Col. Alfred H. Terry, Seventh Regiment Connecticut Volunteers, and Lieut. Col. James F. Hall, commanding battal.

wn of New York Volunteer Engineers, were conspicuous for the zeal

and perseverance with which they discharged the varied duties to which they were assigned. ! :

Captain IIinckel, with one company of the Forty-sixth Regiment New York Volunteers and a small battery, occupied for eight weeks, with credit to himself and conimand, an advanced and exposed position on a hulk in Lazaretto Creek, cutting off boat communication in that direction between Fort Pulaski and the interior.

Lieut. Horace Porter, of the Ordnance Department, rendered important and valuable service. Besides discharging most efficiently the special duties of chief of ordnance and artillery, he directed in person the transportation of nearly all the heavy ordnance and instructed the men in its use. He was actively engaged among the batteries during the action.

Capt. Charles E. Fuller, assistant quartermaster, served with me four weeks, assuming during that time the entire charge of unloadiug the ordnance and ordnance stores from the vessels; a duty which he discharged with a success worthy of special notice.

Lieut. James H. Wilson, Topographical Engineers, joined my command eleven days before the action, and was assigned to duty as instruetor of artillery. He rendered valuable service in that capacity, and also at the breaching batteries on the 10th and 11th.

Capt. Louis H. Pelouze, Fifteenth U. S. Infantry, and Capt. J. W. Turner, commissary of subsistence, U. S. Army, members of Major-General Hunter’s staff, volunteered for the engagement, and were assigned to the command of batteries, where their knowledge and experience as artillerists proved of great value.

On the 11th two pieces of Battery Sigel were served by a detachment from the Eighth Regiment Maine Volunteers, under Captain McArthur. of that regiment. The men had all served exclusively as infantry, an received their first artillery drill from Captain Turner and Lieutenant Wilson under a severe fire. They readily adapted themselves to their new duties, and served their guns creditably.

Capt. F. E. Graef and Lieut. T. B. Brooks, commanding respectively the two companies (D and A) of Volunteer Engineers, were indefatigable in the discharge of their duties as engineer officers, which required them to be out with the working parties every night.

I am under obligations to Commander ©. R. P. Rodgers and Lieut. John Irwin, U. S. Navy, for skillfully serving with a detachment of sailors four siege guns in Battery Sigel on the 11th.

Lieut. W. L. M. Burger, of the regiment of New York Volunteer Engineers, served with zeal and efficiency as my adjutant-general during the operations on Tybee Island.

Lieut. P. H. O’Rorke, of the Corps of Engineers, and Adam Badeau, esq., volunteered to serve as my aides on the 10th and 11th, and rendered valuable assistance.

The services of Sergt. James E. Wilson, of Company A, Corps of Engineers, deserve special mention, and largely contributed towards getting the breaching batteries ready for service. Sergeant Wilson commanded Battery Burnside during the action.

To Major-General Hunter and Brigadier-General Benham, commanding respectively this department and district, I am under obligations — for the official courtesy with which they allowed the project for reducing the fort, which was planned and all but executed before they assumed

their commands, to be carried out in all its details without change or modifieation.

The three breaching batteries—Sigel, Scott, and McOlellan—were established at a mean distance of 1,700 yards from the scarp walls of Fort Pulaski.

The circumstance, altogether new in the annals of sieges, that a practicable breach, which compelled the surrender of the work, was made at that distance in a wall 74 feet thick, standing obliquely to the line of fire and backed by heavy casemate piers and arches, cannot be ignored by a simple reference to the time-honored military maxims that ” Forts cannot sustain a vigorous land attack,” and that “All masonry should be covered from land batteries.”

A comparative glance at the status of military science as regards breaching prior to the invention of rifled cannon will enable us to form a tolerably correct estimate of the importance to be attached to the results developed by this improved arm of the service. A standard military work furnishes the following extract:

An exposed wall may be breached with certainty at distances from 500 to 700 yards, even when elevated 100 feet above the breaching battery; and it is believed that in case of extreme necessity it would be justifiable to attempt to batter down an exposed wall from any distance not exceeding 1,000 yards; but then the quantity of artillery must be considerable, and it will require from four to seven days’ firing, according to the number of guns in battery and the period of daylight, to render a breach practicable.

During the Peninsular war breaching at 500 to 700 yards was of frequent occurrence, and at the second siege of Badajos fourteen brass 24pounders breached an exposed castle wall backed by earth alone, and consequently much weaker than a scarp sustained in the rear by heavy piers and arches, in eight hours, at a distance of 800 yards.

Experiments of breaching with rifled guns have recently been made. I shall notice two cases :

In August, 1860, experiments with Armstrong’s rifled guns were made against a condemned martello tower at Eastbourne, on the coast of Sussex, England. The tower was of brick, fifty-six years old, and designed for one gun, the wall being 74 feet thick at the level of the ground and 53 thick at the spring of the vault, which was 19 feet above the ground. It was 314 feet high, 46 feet exterior diameter at the bottom, and 40 feet at the top. The pieces used against it were: one 40-pounder of 43-inch caliber, one 82-pounder of 6-inch caliber, and one 7-inch howitzer throwing 100-pound shells. A practicable breach, 24 feet wide, including most of the arch, was made with an expenditure of 10,850 pounds of metal, at a distance of 1,032 yards. The projectiles expended were: 40-pounder gun, 20 solid shot, 1 plugged shell, 43 live shells; 82-pounder gun, 19 solid shot, 8 plugged shells, 36 live shells; 7-inch howitzer, 2 plugged shells, 29 live shells.

Projectiles that failed to hit the wall are excluded from the above table.*

General Sir John Burgoyne, in his report upon these experiments, Says:

Trials were subsequently made to breach a similar tower from amooth-bored 68 and 32 pounders at the same range of 1,030 yards, and the result may be deemed altogether 8 failure, both mocncecy: of fire and velocity of missiles being quite deficient for such a range. At 500, or perhaps 600, yards the superiority of the rifled ordnance would BODSUIY have been very little, if any.

Experimental siege operations for the instruction of the Prussian army. comprising the demolition of the defective and obsolete fortifications at

* Reference is to table on the map showing position of the batteries, &o., to appear in Atlas. The table shows that 4,079 shell and 914 shot were fired.

Juliers, were carried on in the month of September, 1860, especially with reference to the effect of rifled breech-loading guns.

The following brief summary of the breaching experiments is taken from the report of Lieut. Col. A. Ross, Royal Engineers:

Four 12-pounder iron guns and two 12-pounder brass guns, weighing, respectively. 2,700 pounds and 1,300 pounds, throwing a conical ball weighing 27 pounds, and fired with a charge of 2.1 pounds, at 800 Prussian paces (640 yards), made a practicable breach 32 feet wide in a brick wall 3 feet thick, with counter-forts 4 feet thick, 4 feet wide, and 16 feet from center to center, the wall being 16 feet high, and built en décharge, after firing 126 rounds. The first six rounds are omitted from this calculation, as they did not strike the wall, the wall being entirely covered from the guns. No difference was observed between the effects of the brass and theiron guns. The bursting charge of the shells was fourteen-fifteenths of a pound. The penetration was 15 inches.

Six 6-pounder guns, four of iron and two of cast steel, weighing, respectively, 1,200 and 800 pounds, throwing a conical shell weighing 13 pounds, and firing with a charge of 1.1 pounds, at 50 paces, made a practicable breach 70 feet wide, in precisely the same description of wall as that above described, after firing 276 rounds, the battery being situated onthe counterscarp opposite the wall. No difference was observed between the effects of the cast steel andiron guns. The bursting charge of a shell was half a pound. The penetration of the first single shot averaged 18 inches.

Four 24-pounder iron guns, weighing between 53 and 54 bundreaelehte throwing a shell weighing 57 pounds and firing with a charge of 4 pounds, at a distance of 60 yards made a practicable breach 62 foot wide in a loop-holed brick wall 24 feet high and 64 thick after firing 117 rounds, the wall being seen from the battery. The bursting charge of the shell was 2 pounds. The penetration of the two first single shots was 24 and 3 feet.

The same guns, after firing 294 rounds with the same charges and at a distance of 96 yards, made a breach 46 feet wide in a brick wall 40 feet high and 12 feet thick at the foot, with a batter of &’out 4 feet. The wall was 12 feet thick, and built en décharge, with counter-forta 6feet wide and 16 feet from center to center, and connected by two rows of arches, one above the other. The penetration of the first single shot was 3 feet and 3j feet. All the above-mentioned guns were rifled breach-loaders.

It is impossible to institute a very close comparison of the relative value of rifled and smooth-bore guns for breaching purposes from any data which experience has thus far developed.

The experiments at Eastbourne, hereinbefore mentioned, are the only ones on record where they have been tried side by side to the extent of actual breaching against the same kind of masonry and at the same distance. We have seen how on that occasion the rifles were a complete success, while the smootb-bores were an utter failure.

At Fort Pulaski an excellent opportunity was afforded on the scarp wall near the breach for obtaining the actual penetration of the several kinds of projectiles. An average of three or more shots for each caliber was Pom giving the following results, which may be relied upon as correct :

Table of penetrations in a briok wall, as eae at the siege of Fort Pulaski, Ga., April,

Kind ut gun. sa Kind and weight of projectiles. g 3 i

H5 4 Old 42-pounder, mfled James, 841lbs., solid ………… 4 RS vu Old 32-pounder, rifled James, 64 Ibs., solid ………… 4 6 20 Old 24-pounder, rifled James, 48lbs., solid …. — 44 5 19 Parrott rifled gun ……………. oe Parrott, 30 lbs., solid …. mai 34 18 Columbiad (10-inch), smooth bore…… 1,740 Parrott, 128 lbs., solid round ….. Fi 20 13 Columbiad (8-inch), smooth bore……. 1,740 Parrott, 68 lbs., solid round ….. 5 10

The above table indieates very prominently, although it affords no exact means of measuring, the great superiority of rifle over smooth bore guns for purposes requiring great penetrating power.

Against brick walls the breaching effect of percussion shell is certainly as great as that of solid shot of thesame caliber. They do not penetrate as far by 20 to 25 per cent., but by bursting they make a much broader crater. Such shell would doubtless break against granite walls without inflicting much injury.

Sir W. Dennison, from a comparison of the several sieges in Spain during the Peuinsular war, estimated that a practicable breach at 500 yards could be made in a rubble wall backed by earth by an average expenditure of 254,400 pounds of metal fired from smooth-bore 24-pounders for every 100 feet in width of breach—equal to 2,544 pounds of metal for ever linear foot in width of breach.

Before we can draw any comparison, however imperfect, between this estimate and the results obtained at Fort Pulaski, it is necessary to make certain deductions from the amount of metal thrown from the breaching batteries used against that work, as follows:

First. For the shots expended upon the barbette guns of the fort in silencing their fire.

Second. For 10 percent. of Parrott projectiles, which upset from some defect which I i now from personal observation has been entirely removed by the recent improvements of the manufacturer.

Third. For nearly 50 per cent. of the 64. pound James shot, due to the fact that one of the two pieces from which they were thrown had by some unaccountable oversight been bored nearly one-fourth of an inch too large in diameter, and gave no good firing whatever. Making these deductions, it results that 110,643 pounds of metal were fired at the breach.

The really praetieable portion of the breach was of course only the two casemates that were fully opened, say 30 feet in aggregate width; but the searp wall was battered down in front of three casemate piers besides, and had these piers not been there, or had the scarp been backed by earth alone, as was generally the case in Spain, the practicable portion of the opening would have been from 45 to 50 feet wide. Calling it 45 feet, the weight of metal thrown per linear foot of breach was 2,458 pounds, against 2,544 per linear foot in the Peninsular sieges. Had the fort held out a few hours longer this difference would have been much greater, for the wall was so badly shattered to the distance of 25 or 30 teet each side of the breach that the opening could have been extended either way with acomparatively trifling expenditure of metal. On repairing the work 100 linear feet of the scarp wall had to be rebuilt.

It must be borne in mind that at Fort Pulaski only 58 per cent. of the breaching metal was fired from rifled guns, the balance being from smooth-bored 8-inch and 10-inch columbiads (68 and 128 pounders) of Battery Scott.

It may therefore be briefly and safely announced that the breaching of Fort Pulaski at 1,700 yards did not require as great an expenditure of metal, although but 58 per cent. of it was thrown from rifled guns, as the breaches made in Spain with smooth-bores exclusively at 500 yards. In the former case the wall was good brick masonry, laid in lime mortar, and backed by heavy piers and arches; in the latter, rubble masonry, backed by earth. :

A knowledge of the relative value of heavy round shot, 10-inch for example, and elongated percussion shells from lighter guns, say James 64-pounders (old 32-pounders), in bringing down the masses of brick masonry cracked and loosened by the elongated solid shot, is a matter of some importance, considering the vast difference in the amount of labor required to transport and handle the two kinds of ordnance. The

164 . OcOASTS OF 8. C., GA., AND MIDDLE AND EAST FLA, (Cmr. XV.

penetration of the percussion shell would exceed, and its loeal effect would at least equal, that of the solid round shot. The general effect of the latter, within certain ranges, is a matter for consideration.

My own opinion, based principally upon personal observation, eorroborated by the reports of éxperiments made in Europe, may be stated in the following terms:

First. Within 700 yards heavy smooth bores may be advantageously used for breaching, either alone or in combination with rifles.

Second. Within the same distance light smooth bores will breach with certainty, but rifles of the same weight are much better.

Third. Beyond 700 yards rifled guns exclusively are much superior for breaching purposes to any combination of rifles and heavy or light smooth bores.

Fourth. Beyond 1,000 yards a due regard to economy in the expenditure of manual labor and ammunition requires that smooth bores, no matter how heavy they may be, should be scrupulously excluded from breaching batteries.

Fifth, In all cases when rifled guns are used exclusively against brick walls at least one-half of them should fire percussion shells. Against stone walls shell would be ineffective.

For breaching at long distances the James and Parrott projectiles seem to be all that can be desired. The grooves of the James gun must be kept clean at the seat of theshot. This is not on,y indispensably necessary, but of easy and ready attainment, by using the very simple and effective scraper devised on the principle of the searcher for the pieces we employed against Pulaski. This scraper consists of a number of steel springs or prongs, one for each groove, firmly attached by screws to the cylindrical part of a rammer-head, and flaring like a broom, so as to fit closely into the grooves. About half an inch of the lower end of each prong is bent out at right angles. The prongs being compressed by a ring, to which a lanyard is attached, when entering the bore spring out firmly into the grooves when the ring is removed, and clean them thoroughly as the scraper is drawn out.

The failure of the James shot, as reported on two or three occasions by apparently good authority, is probably due to neglect in this particular. There were no failures in our firing, except as before mentioned with the 32-pounders (carrying a 64-pound shot), that had been bored too large.

Although the James projectiles are surrounded when first made by greased canvas, there is believed to be an advantage in greasing them again at the moment ofloading. This was done in our batteries against Fort Pulaski. As the Parrott projectiles receive their rotary motion from a ring of wrought-iron or brass which surrounds the lower portion of the cylinder, and which does not foul the grooves while engaging them, no special precaution to prevent fouling need be taken with the Parrott guns.

With heavy James or Parrott guns the practicability of breaching the best-constructed brick scarp at 2,300 to 2,500 yards with satisfactory rapidity admits of very little doubt. Had we possessed our present knowledge of their power previous to the bombardment of Fort Pulaski, the eight weeks of laborious preparation for its reduction could have oeen curtailed to one week, as heavy mortars and columbiads would have been omitted from the armament of the batteries as unsuitable for breaching at long ranges.

It is also true beyond question that the minimum distance, say from 900 to 1,000 yards, at which land batteries have heretofore been conCmar XYV.] FORT PULASKI.

sidered praetieally harmless against exposed masonry, must be at least trebled, now the rifled guns have to be provided against.

The inaccuracy of the fire of the 13-inch mortars has already been adverted to. Not one-tenth of the shells dropped inside of the fort. A few struck the terre-plein over the casemate arches, but, so far as could be observed by subsequent inspection from below, without producing any effect upon the masonry. Whether they penetrated the earth work to the roofing of the arches was not ascertained.

Two or three striking in rapid succession into the same spot over an arch might be expected to injure it seriously, if not fatally. Such an occurrence would, however, be rare indeed. Against all, except very extraordinary casualties, it would be easy for a garrison to provide as they occurred, by repairing with sand bags or loose earth the holes formed in the terre-plein by shells.

We may therefore assume that mortars are unreliable for the reduction of a good casemated work of small area, like most of our sea-coast fortifications.

As auxiliary in silencing a barbette fire, or in the reduction of a work containing wooden buildings and other exposed combustible material, mortars may undoubtedly be made to play an important part.

For the reduction of fortified towns or cities, or extensive fortresses containing large garrisons, there is perhaps no better arm than the mortar, unless it be the rifled gun, firing at high elevations.

To the splinter-proof shelters constructed for the seven advanced batteries I attribute our almost entire exemption from loss of life. We had 1 man killed by a shell from one of the mortar batteries outside the fort, which was the only casualty.

The demoralizing effect of constant and laborious fatigue duty upon the health and discipline of troops, particularly upon such as are unused to the privations of war, like our volunteers, who can but slowly adapt themselves to the stinted comforts of a campaign, is a subject which demands the earnest attention of commanding officers in the field.

Upon regular troops, to whom the drill in their special arm has to a certain extent become a second nature, who are accustomed to the vicissitudes of the field and familiar with expedients and make-shifts to secure comfort, the bad effects of excessive labor and constant interruption of drill are of course less apparent.

With the average of our volunteer regiments every alternate day should be devoted to drill, in order to keep them up to a fair standard of efficiency.

Very respectfully, your obedient servant,

Major-General Volunteers.

To the ADJUTANT-GENERAL U. S. ARMY,

Washington, D. C.

No. 6.

Report of Surg. George E. Cooper, U. 8. Army.

MEDICAL DIRECTOE’S OFFICE, DEP’T OF THE SOUTH,

Hilton Head, S. O., April 14, 1862.