For vertical plotting, take the distance short, or over, from the target that the projectile strikes, from Buckner's tables; with these distances pick out the vertical co-ordinates from table III of the "Tables for plotting gun practice," now furnished to ships.

The data for this method is easily obtained without interfering with or delaying the practice in any way, the shots are quickly plotted and the record is easily made up after the practice is over. But one of the most important points with this method is that the firing is continuous from the moment of commencing with one battery until all the guns on that side have fired their allowance. The firing is therefore spirited, and a lively interest is taken in it both by officers and men. It is much more natural that this should be so than in a practice which is interrupted by the ship swinging (at anchor) so as to prevent certain guns from bearing on the target, or smoke hanging around the ship so that the target cannot be seen. At the same time the method is as simple as though the ship were at anchor. Still, it may be considered preferable to anchor the ship, and if so, desirable places are easily found in our own waters; but this is not always the case on foreign stations, and such places where target practice with great guns can be carried on without offense to or objection by foreign powers are sometimes found with difficulty, if at all. By dropping the target and steaming around it in an approximate circle, as just described, target practice may be had at almost any time when a ship is at sea. It also takes considerable time. to anchor, send out a target, place the buoys now used on each side of it, and station the boat containing the right or left observer.

A disadvantage of the present method of stationary practice (and in fact of all methods of practice requiring observers in boats) is that a smooth sea is necessary to make the boat observations of any value. A smooth sea may ordinarily be found in such favored places as Long Island Sound, Gardiner's Bay, Chesapeake Bay, and around Key West. But on foreign stations it is otherwise, and considerable difficulty is sometimes experienced in finding a favorable place for target practice with our long-range guns. A case is recalled when target practice commenced under such circumstances on a foreign station. The sea was smooth, and there was but little wind. Shortly afterwards a moderate breeze sprung up, but there was not enough wind to interfere with the firing. The short, choppy

and it was found that their observations were of but little value in plotting the shots to make up the record. This could not have happened if the observations had all been made from the ship.

It is to be regretted that Buckner's method is the only one that appears at present to be feasible for the complete observation of fall of shots from the ship, as it is not very accurate, and for that reason probably has become obsolete. But it gives, perhaps, as good results as observations taken from boats, except under favorable circumstances, and it is not always convenient to wait for such conditions. If the method involving the use of Buckner's tables will give results sufficiently accurate to furnish data from which to draw conclusions to enable us to correct the gun captain's firing, and also make up a record with which to compare the various gun captains' marksmanship, it is sufficiently accurate for our purposes.

SECOND METHOD.

MOVING PRACTICE.

The objects in this method will be:

Ist. To maintain a continuous, spirited firing from either the starboard or port battery from the time of commencing until all the guns of that battery have fired their allowance. The men would probably take more interest in the practice than they would if the ship steamed over a short range on one course for perhaps only ten minutes and then spent some little time to turn and get on the range to steam back. It is tiresome and uninteresting to stand at the guns waiting to fire.

2d. To lay the targets out quickly and easily and commence practice with but little delay.

3d. To have practice at sea at almost any time.

4th. To use no boats for observers; practice can then take place under circumstances of wind and sea that would make it impossible to have it if boats were used.

The system proposed is to use three floating targets, all alike, so that once dropped from the ship they will drift at about the same speed and maintain approximately their relative positions from each other.

Suppose the ship to be steaming along at a uniform

After steaming say 1500 yards on the same course, the second target, B, is dropped. The third target, C, is dropped by bringing either A or B on the proper bearing and steaming towards it until the angle between A and B (set on a sextant) gives the correct position to drop C. In the figure the ship is steaming towards A, where she drops the first target. Without

changing course, she steams 1500 yards and drops the second target at B. She then changes course, as shown by the dotted line, and steams around until she brings B on the proper bearing, when she steams slowly towards it, keeping it on the proper compass bearing. When the angle between A and B is 60°, the target C is dropped; the ship then steams around all three targets, firing at them in succession until the allowance of ammunition for the battery on that side is expended. She then turns and steams in the opposite direction, mans the other battery, and fires until its allowance is expended.

Suppose the starboard battery to be the first one to fire. After dropping target C, the ship steams in the direction of B

would be 1500 yards. This is a special case of the first method described, using a single target, and should be avoided to give the gun captains practice in training their guns. When the ship arrives at A the target B is fired at until C is reached, when A is fired at until the ship arrives at B. The same observers are required as in the one target method, already explained. The plotting is done in the manner described for that method.

On soundings, the targets could, of course, be anchored; but the advantage of the method (if there is any) would be that it could be used at sea off soundings under circumstances when observers in boats could only obtain observations that would be of but little value in plotting the shots. This might be of considerable importance on a foreign station where there may be difficulty in finding a good target ground outside of foreign jurisdiction.

It seems quite probable that objection will be made to the use of Buckner's method. But is the present method of observation and plotting always more satisfactory than this would be?

2121 YOS

1500 ros

8

1500 YDS

C

Suppose that with the present method a target is laid out at A and the ship steams over

a range between two buoys, B and C, 3000 yards apart, at a speed

of ten knots, firing at the target A while between the buoys. She will steam across the range in about nine minutes. Leaving or approaching a buoy at either end of the range, the distance from the target will vary 200 yards in less than a minute. The observations for plotting the fall of shots under these circumstances may not, perhaps, be any more accurate than those obtained by using Buckner's method.

The preceding is offered not in any sense as a criticism of present methods, but merely as a suggestion of methods that may, under certain circumstances, be more advantageously employed in target practice on board our cruisers, particularly on

U. S. NAVAL INSTITUTE, ANNAPOLIS, MD.

NAPHTHA FUEL FOR WAR-SHIPS.

BY LIEUT. M. VASILIEFF, RUSSIAN NAVY.

Translated from the Russian (Morskoi Sbornik, August, 1896) by Lieut. John B. Bernadou, U. S. N.

In submitting a sketch of the development of the employment of naphtha fuel for war-ships, I do not pretend to say much that is new; but information on this subject is so little spread in our Navy that even an elementary sketch should contribute its share of usefulness, especially in view of the probable employment of naphtha fuel on ships of war in the very near future.

First of all, the naphtha serving to heat steam boilers should not be confounded with raw naphtha or kerosene. Both of these latter substances are easily inflammable, as they contain various more or less volatile hydrocarbons (on account of the presence of which they possess a characteristic odor), while the naphtha which we are now considering, and which is commonly called "mazut," is the residue from the distillation of raw naphtha after the kerosene, benzene and other coal derivatives with low ignition points have been expelled therefrom. Naphtha residue is a yellow brown, thick oily liquid; its specific gravity and ignition temperature depend upon the degree of distillation to which the raw naphtha has been subjected, or upon the temperature at which the process has been conducted. For general purposes of navigation the residue is completely safe when it possesses a specific gravity 0.92 and an ignition temperature

*This substance is hereafter referred to in this translation as "naphtha