EXAMINATION OF FIRST-CLASS GUNNERS.
(a) THE AZIMUTH INSTRUMENT AND DEFINITIONS.
Q. What is an angle?
A. An angle is the divergence of two intersecting lines.
Fig. 57.
In Fig. 57 the two intersecting lines SA and XA form the angle SAX, and when measured on the circle with A as the center it is found to be equal to 80°.45 (eighty and forty-five hundredths degrees).
Q. Into how many degrees is a circle divided?
A. 360.
Q. How is each degree divided in the U. S. Artillery service?
A. Each degree is divided into one hundred equal parts.
Q. Define a circle.
A. A circle is a plane figure bounded by a curve, every point of which is equally distant from a point within called the center. Fig. 57 represents a circle with A as the center.
Q. What is the vertex of an angle?
A. The point where the two intersecting lines cross. As in Fig. 57, A is the vertex of the angle SAX.
Q. Define an azimuth angle.
A. It is a horizontal angle measured from zero degrees at the south in a clockwise direction.
Q. What is meant by a horizontal angle?
A. One whose intersecting lines or sides are parallel with the level of water at that point.
Q. What is a vertical angle?
A. One whose sides lie in a plane of a plummet.
Q. Can an azimuth angle be greater than 90°?
A. Yes. See Fig. 51. SAT = azimuth of target (less than 90°); SAT' = azimuth of target (greater than 90°, but less than 180°); SAT'' = azimuth of target (greater than 270°). (All these azimuth angles are read in a clockwise direction from zero at the south.)
Q. When is a gun or an instrument said to be set in azimuth?
A. When it reads zero and points south.
Q. What is an azimuth-instrument?
A. A device for measuring horizontal angles.
Q. Point out the following parts of the instrument:
| 1. | Telescope-tube. |
| 2. | Telescope-trunnion. |
| 3. | Trunnion clamp-screws. |
| 4. | Focusing-knob. |
| 5. | Sunshade. |
| 6. | Dew-cap. |
| 7. | Objective-cell. |
| 8. | Objective. |
| 9. | Eyepiece-adapter. |
| 10. | Eyepiece. |
| 11. | Eye-lens. |
| 12. | Field-lens. |
| 13. | Cross-wire holders. |
| 14. | Cross-wire. |
| 15. | Brashear-Hastings erecting-prism. |
| 16. | Prism-holder. |
| 17. | Prism-cap. |
| 18. | Cross-wire adjusting-screw. |
| 19. | Instrument-base. |
| 20. | Leveling-screws. |
| 21. | Spindle-head. |
| 22. | Worm-gear. |
| 23. | Graduated circle. |
| 24. | Worm-screw. |
| 25. | Worm-box. |
| 26. | Worm-box spring. |
| 27. | Worm-box pivot. |
| 28. | Worm-box adjusting-screws. |
| 29. | Worm-box eccentric-crank. |
| 30. | Index-disk. |
| 31. | Index-pointer. |
| 32. | Disk-crank. |
| 33. | Worm adjusting-screw. |
| 34. | Reading-opening. |
| 35. | Azimuth-clamp. |
| 36. | Azimuth slow-motion screw. |
| 37. | Telescope-yoke. |
| 38. | Yoke-caps. |
| 39. | Levels. |
| 40. | Level-holders. |
| 41. | Level-adjusting screws. |
| 42. | Plumb-bob. |
| 43. | Plumb-bob chain. |
| 44. | Tripod-head. |
| 45. | Tripod-cap. |
| 46. | Tripod-thumbscrew. |
| 47. | Tripod-legs. |
| 48. | Pier-mounts. |
A. See Fig. 58.
Q. Describe how to set the azimuth-instrument up for use.
A. First: Set the graduated circle and index-disc to read the known azimuth of a visible object and clamp (the eccentric-crank being in gear).
Second: Set the eyepiece slightly to the left of the reading-opening and tighten the azimuth-clamp.
Third: Raise the whole instrument by grasping the tripod, and turn it so that the telescope points approximately in the direction of the visible object whose azimuth is known, being careful to set the plumb-bob over the home station at the same time and not destroy the setting of the graduated circle and index-disc.
Fourth: Level the instrument. (This is done by loosening the azimuth-clamp and setting one level parallel to two opposite leveling-screws, then turn these two screws either both inward toward the spindle-head or both outward until the bubble comes in the middle. Perform the like operation with the other two leveling-screws and the instrument is level.)
Fifth: Release the azimuth-clamp and set the telescope as nearly as possible on the object, then clamp and set the vertical cross-hair exactly by turning the azimuth slow-motion screw. Verify the setting of the index-disc and the levels. The instrument is now set in azimuth. Azimuth instruments for mounting on the parapet have turned on their levelling screws so as to bring reading opening convenient to the eye.
Q. How is the azimuth of any other point read after the instrument is set up?
A. By turning the index-disc crank until the vertical hair cuts the object. Read the even degrees on the graduated circle, and hundredths of a degree on the index-disc. (In order to make a considerable change in azimuth-reading, much time is saved by releasing the eccentric-crank, turning the telescope approximately on the object, throwing the eccentric-gear again and reading accurately by turning the index-disc till the vertical hair cuts the object.)
Q. Why are not azimuth-circles on guns, mortars, etc., always graduated so that their zeros will point south?
Fig. 58.
A. If this were always done, the azimuth indicator-plate or subscale would have to be directly under the muzzle of the gun—a very awkward and inconvenient place. These azimuth sub-scales are therefore placed on the side, and when the gun or mortar points south the subscale points at zero on the azimuth-circle.
Q. Give some rules for caring for the azimuth instrument.
A. Never allow any of the leveling-screws to become so tight that they cannot be easily turned by hand. When setting the instrument up over a concrete floor make little holes in the concrete for the points of the tripod-legs to set in. Never wipe the lenses with anything having the least sign of dirt or grit upon it. A perfectly clean chamois is always best. See that all screws are firmly clamped before putting the instrument away in the wooden carrying-box. In removing it from the box, pick it up by placing the hands underneath the worm-gear. Never clamp the instrument too tightly to the tripod-head. After the instrument is once leveled avoid jarring or leaning upon it.
Q. In case the azimuth-instrument will not stay level after performing the usual operation of leveling, how do you adjust the levels?
A. Set one level parallel with two opposite leveling-screws, and bring the bubble to the center by turning these two screws either both inward or both outward. Reverse the telescope through 180°. If the bubble is not in the center, this level is out of adjustment. Now correct one half of the error by using the small steel pin on the little adjusting-screws on the levels, and the other half by using the two opposite leveling-screws referred to above. Now turn the telescope 180° again. If it is still out of level, continue the above method of correction until, on reversing the telescope, no change in motion of the bubble can be observed.
Q. Give a rule for finding the least count of a vernier.
A. Divide the value of the smallest division on the limb or main scale by the number of divisions there are on the vernier. The result is equal to the least count on the vernier.
Q. How would you focus the telescope.
A. Focus the eyepiece until the cross-wires appear rough.
Then turn the telescope on some distant object and focus the objective by means of the focusing-knob until the intersection of the cross-wires remains on the same point, when the eye is moved up and down and to right and left.
Q. Set up the azimuth instrument over a given point; level, orient, and focus it.
(This should be practiced frequently.)
Examples.—I. The number of divisions on a vernier = 25. The value of the smallest division on the main scale = 25 yards. What is the least reading of the vernier?
Ans. 25 ÷ 25 = 1 yard.
II. The value of the smallest division on the main scale of the mercurial barometer = 1/10 of an inch. The number of divisions on the vernier = 10. What is the least count of the vernier?
Ans. 1/10 ÷ 10 = 1/100 of an inch.
Note.—The following scheme for accurately counting seconds has been found valuable to gunners who have no stop-watches; it is also used by many photographers in timing pictures. When ready to start to count the time of flight, for example, trail your gun or instrument on the target, stop traversing, and count to yourself: One one thousand, two one thousand, three one thousand, four one thousand, etc., until finished, saying one thousand after each number. The time required by the average man to say one one thousand or eight one thousand is equal to one second. With but little practice a gunner can be trained to count as high as 20 seconds accurately. In such cases stop-watches are not necessary.
(b) THE PLOTTING-ROOM.
Q. Point out or describe the following parts of the Whistler-Hearn plotting-board: The table, the azimuth-circle, azimuth graduations for primary and secondary stations, base-line arm, base-line plate, primary station, secondary station, primary arm, secondary arm, directing-gun arm, directing-gun azimuth-circle, base-line verniers, directing-gun vernier, base-line-arm verniers, azimuth-indices for primary and secondary stations, auxiliary arm, connecting-bar, clamp for arm index-clamp, gun-arm clamp, reading-opening for directing-gun azimuth-circle, index for gun azimuth-circle, speed-scale for range, speed-scale for azimuth or azimuth-travel devices, range correction-device, azimuth correction-device, micrometer, the "targ, tally dials."
A. See Figs. 59, 60, 61, and 62. These figures show by steps the "evolution of the Plotting Board."
SIMPLE PLOTTING-BOARD.
Fig. 59.
PLOTTING-BOARD WITH GUN-ARM.
Fig. 60.
Q. Describe how to obtain the range of a target from the primary or secondary station when the azimuth-angles from the primary and secondary stations are given to you.
A. First: Set the auxiliary-arm index to read the number of even degrees the target is from the secondary station, setting the arm-clamp in the V-shaped notch on the azimuth-circle corresponding to that number of degrees.
THE MODERN PLOTTING-BOARD.
Fig. 61.
Second: Set the index-disc to read the hundredths by turning the index-knob and clamp the index. The auxiliary arm is now set; therefore the secondary arm is set automatically in azimuth by virtue of its always remaining parallel to the auxiliary arm.
Third: Set the primary arm to read the number of degrees and hundredths the target is from the primary station. (The point of intersection of the fiducial or bevel edges of the primary and secondary arms is the position of the target on the plotting-board.)
Fourth: Slide the metal intersection-block or "targ" along the secondary arm until it touches the edge of the primary. The range in yards can now be readily read on the scales marked on these arms. (Fig. 62.)
WHISTLER-HEARN PLOTTING-BOARD. (Perspective Drawing. Secondary and auxiliary arms should be parallel.)
Fig. 62.
Q. How are the range and azimuth for the directing-gun obtained for the same target?
A. Move the gun-arm up to the intersecting edge of the targ, and read the range from the scale on the gun-arm. The degrees of azimuth are read through the reading-opening, and the hundredths are read on the index-disc for the gun-arm.
Q. Suppose the range must be corrected for, say, 150 yards more, and the azimuth for 1·78 degrees less, how can the corrected range and corrected azimuth be automatically read on the gun-arm?
A. Turn the pinion on the gun-arm to move the scale of the range correction-device until 2150 is set. (The zero of this scale = 2000.) (By doing this it is readily seen that the gun-arm range-scale is just 150 yards nearer the gun center; consequently all ranges read on this scale will be 150 yards more than if the range correction-device were at zero.) The azimuth correction is set by turning the micrometer until the number of even degrees of the azimuth correction (in this case one degree less) is read on the main scale, and the hundredths on the micrometer. (Thus it is seen that the gun-arm will read as many degrees and hundredths more or less than the true azimuth as the number of degrees and hundredths of the azimuth correction determined.)
Note.—Having determined by the ballistic board the range and azimuth corrections, they will usually answer for some time and thus avoid continual setting of these corrections on the gun-arm.
Q. What is the object of the travel-devices for range and azimuth correction on the gun-arm?
A. These are to determine the amount of change of range and azimuth between each observation of the target. The results thus obtained are given to the range- and deflection-board operators, who use it in finding the total range correction and the total azimuth correction.
Q. What are all plotting-boards principally used for?
A. For finding the position of a target whereby the range and the azimuth of it from any other point (as a directing-gun of a battery) can be determined.
Q. What is meant by the scale of a plotting-board?
A. By the scale of a plotting-board is meant, one inch on the board is equal to one, two, or so many yards on the ground; e.g., a scale of "one inch equals 300 yards" means, one inch distance on the board equals 300 yards on the ground.
Q. How can you determine the distance between two points on a plotting-board?
A. By using the range-arm that is constructed for the scale to which the board is drawn, setting the zero on one point and reading the number of yards on the arm where the point cuts the scale-edge.
Q. How is the longitudinal deviation measured on the plotting-board?
A. Measure the distance from the gun to the target, and from the gun to the splash. Subtract the lesser from the greater, and this will be the longitudinal deviation, according to the meaning given in drill regulations.
Q. How is the lateral deviation measured?
A. Read the azimuth of the target and splash from the directing-gun. Subtract the lesser from the greater: result = lateral deviation. If the azimuth to the target be greater than that to the splash, it is seen that the deviation will be to the left and vice versa.
Q. How are open sights on rapid-fire guns used?
A. The same as on small-arm pieces; i.e., the range in yards or elevation in degrees and minutes is set on the rear sight according to how the sight is graduated, and the gun is elevated and traversed until the target, front sight, and rear sight all come in line.
Q. Describe the 5" R.F. sight.
A. It consists of a sight-bar graduated in degrees and minutes (lowest reading being six minutes), with a sliding scale at the top for deflection right or left, the deflection-scale reading to three minutes. A range-drum is also geared to the sight-bar, and moves with it in such a manner that when the piece has a certain elevation it will shoot to a distance equal to the range on the drum. This avoids using any range-table.
Q. Describe the 6-pdr. R.F. sight.
A. A simple bar-sight graduated to yards with a deflection-scale reading to three minutes.
Q. How is the deflection-scale set on open sights when it is desired to fire to right or left?
A. To fire right, move the peep-hole to the right; to fire left, move the peep-hole to the left.
Q. From what line is all elevation measured?
A. From the axis of the bore. (See Fig. 63.)
Fig. 63.
Q. Define sight elevation.
A. The angle between the axis of the bore before firing and the line of sight. (See Figs. 63 and 64.)
Q. In case shot strikes to the right or left, and as gunner you had the sight on the target when the shot struck, how could you correct your error with a telescopic sight or open sights?
A. Stopping traversing at the instant shot strikes, move the vertical hair rapidly to the splash. The sight is now corrected for the error, and its setting will be correct for the next shot.
The Range-board.
NOMENCLATURE. (See Fig. 65.)
The Frame.—The outside frame, or box, of the instrument.
The Board.—That upon which the charts are pasted. K-K.
SIGHT SET FOR "QUADRANT ELEVATION"
SIGHT SET FOR "SIGHT ELEVATION"
(EXAGGERATED DIAGRAMS.)
Fig. 64.
The Ruler.—The balance wooden strip to which the metal scale and slides are attached. X-X.
The Scale.—The fixed graduated scale on the ruler. m-m.
The Bar.—The metal rod or bar which slides on the top of the scale.
The Register.—The fixed point in the center of the bar. a.
The Trammel.—The pointer which slides on the bar. b.
The Pointer.—The pointer at the top of the trammel.
The Index.—The lower point on the trammel.
Normals.—The straight vertical lines in each set of curves.
The String.—The cord on the right side of the board used in determining travel.
The Travel-scale.—Scales for setting the string.
Prediction-scale.—Vertical lines on the right side of the board, used in determining the travel during the observing interval.
ADJUSTMENT.
Adjust the ruler by means of the adjusting-screw on the left, so that its upper edge coincides with the parallel lines on the board.
OPERATION.
The bar is clamped by means of the screw near the left end of the ruler.
The bar must be held firmly while moving the trammel. In making corrections for artillery fire the following data, as obtained at the opening of the action, will usually suffice for the entire action.
Density of the air,
Velocity of the wind,
Azimuth of the wind,
Height of tide.
The range effects and deviating effects of the wind must be obtained for each shot. Tide should be changed at least every half-hour. As soon as the density of the air is ascertained the computer will insert a pin, or set the pointer at the top of the corresponding curve. The same will be done for height of tide.
The muzzle velocity to be used for the first shot will be marked in a similar manner as directed by the range officer. The wind-component device having been set for the azimuth and velocity of the wind and the azimuth of the target, the computer will note the reference-number and set the pointer at the top of the wind-curve having that number.
THE RANGE-BOARD.
Fig. 65.
As soon as he receives the travel reference-number he will set the string accordingly, using the scale for the observing interval used.
To determine correction.—As soon as the approximate range is received, the computer sets the ruler for the range and the index at zero; he then slides the trammel to the left until the pointer is opposite the atmosphere curve as indicated by the pointers e, f, g, etc., holding the bar in place with the left hand. He then slides the bar until the pointer is at normal for atmosphere; this completes the correction for atmosphere.
He then proceeds in the same manner for wind and tide, always sliding the trammel until the pointer is at the indicated curve, holding the bar in place with the left hand and then sliding the bar until the pointer is at normal.
If the muzzle velocity is normal, no correction is made for velocity. If, however, the muzzle velocity is not normal, he makes a correction for muzzle velocity in a similar manner as for other data.
The above corrections are made before the travel is received. The computer clamps the bar and then waits until he receives the travel.
As soon as the travel is received, he sets the string, slides trammel until the pointer is opposite the string, unclamps the bar and moves it until the pointer is opposite the normal; this adds the correction for travel during the time of flight.
He then notes the total travel during the observing interval, which is indicated by the position of the string on the travel-scale corresponding to the observing interval used. He slides the trammel so that the pointer will be at the vertical line corresponding to the total travel during the observing interval, and then slides the bar to the normal; this adds the travel during the observing interval. He now clamps the bar. The register now indicates the total correction to be applied to the arm.
Trial-shots.—The gun is laid so that the shot should have a certain range, all corrections having been determined as described above, except of course that for travel.
The bar is set with the index at zero, and the trammel is set at the muzzle velocity used in the computation for the shot.
The gun is fired and the range of the shot is plotted. The range officer determines how much the shot has fallen short or gone beyond, and announces the result as plus or minus so many yards. The computer moves the bar plus or minus the number of yards announced, using the scale for this purpose.
The pointer now indicates the muzzle velocity to be used in computing the next shot. The velocity pointer is moved accordingly.
If a second trial shot is used, the corrections are computed as before, using, however, the new muzzle velocity as determined from the first shot.
In determining a second corrected muzzle velocity the bar should be moved for but half the longitudinal deviation of the shot from the expected range; the pointer then marks the velocity to be used for the next shot.
In case a third trial shot is used the process is the same except that the bar is moved for but one third of the longitudinal deviation.
The curves are given for every ten yards of range, for every ten per cent of weight of air, and for every ten miles of wind, etc.
For conditions in which the values lie between these readings, the trammel can readily be set by the eye sufficiently close for all practical purposes.
Example: Range 7000; atmosphere 20; wind 70; velocity 2260; travel 400; tide +10. Find the correction to be applied to the gun-arm.
Solution:
The range correction is now found on scale mm opposite pointer a. This number is now set on the gun-arm of the plotting-board and each next plotted position will read on the range-scale of the gun-arm just that many yards more or less than the true range, i.e., the corrected range.
See Fig. 65.
The Deflection-board.
NOMENCLATURE.
Platen.—The rectangular sliding frame.
Wind-arm.—The arm pivoted to the board on the left of the platen.
Wind-component Scale.—The scale above the movable end of the wind-arm.
Drift-curve.—The curved edge of the metal plate attached to the left end of the platen.
Travel-arm.—The arm pivoted on the platen.
Azimuth Correction-scale.—The sliding scale below the platen.
Deflection-scale.—The fixed scale immediately above the azimuth correction-scale.
THE DEFLECTION-BOARD
Fig. 66.
Travel-scale.—A scale for making corrections for angular travel of the target; there are two, one below the azimuth correction-scale and one on the platen.
"T" Square.—The sliding "T" square having the time graduations at one edge, corresponding to given ranges.
OPERATION.
Place the travel-scale on the platen in the lower or upper position according as the observing interval is 10 or 20 seconds.
As soon as the wind-component device is set note the deflection reference-number indicated, and set the wind-arm to the corresponding reading on the wind-component scale.
Set the platen so that the point of the drift-curve corresponding to the given range will be accurately over the right-hand edge of the wind-arm.
As soon as the reference-number indicating the angular travel of the target during the observing interval is announced, set the travel-arm (right edge) for that travel by the travel-scale on the platen and set the azimuth correction-scale for the same travel by means of the travel-scale below it.
Set the "T" square so that the point of its scale corresponding to the given range will be accurately over the right edge of the travel-arm.
The azimuth correction to be applied to the gun-arm in all cases is then read from the azimuth correction scale at the bevel edge of the "T" square.
When Case I or II is being used the deflection to be sent to the guns is read from the deflection-scale at the bevel edge of the "T" square.
After the second observation the corrected range determined is used in setting the platen and "T" square.
See Fig. 60.
Q. How do the divisions on the azimuth-subscale and the deflection-scale of the sights compare with one another?
A. They are equal—the least reading on the former = 5 hundredths, and on the sight-scale one point or division = 5 hundredths or 3 minutes.
Q. How are the predicted range and predicted azimuth obtained?
A. It is now, under the new system of fire direction, obtained by means of the travel correction on the range correction and azimuth correction-board. If these new boards are not yet issued, the use of a range-keeper's range prediction-scale and a gunner's azimuth prediction-scale determines them at the gun. The old method was by plotting several positions of a target on the plotting-board and using a prediction-ruler, whence the predicted point was obtained.
Q. Define quadrant elevation.
A. The angle between the axis of the bore before firing and the horizontal plane. (See Figs. 63 and 64.)
Q. What is the difference between quadrant and sight elevation?
A. Where the gun is above the target, sight elevation equals quadrant elevation plus the angular depression of the target. Where the gun is below the target, sight elevation equals quadrant elevation minus the angular elevation of the target.
Q. How is the gunner's quadrant used?
A. It is used principally in giving elevation to mortars by first setting the movable arm such that the knife-edged tooth engages in an even-degree mark on the rack, and by moving the sliding level to read the exact number of minutes. Then it is placed on its seat at the breech, being careful to see that the arrow points in the direction of the line of fire, and by elevating or depressing the piece until the bubble comes in the middle the mortar or piece will be set at the elevation set on the quadrant. (See Fig. 67.)
THE GUNNER'S QUADRANT.
Fig. 67.
Q. Point out the following parts of the telescopic sight: Telescope, objective, eyepiece, erecting-prisms, trunnions, leveling-lug, leveling-screw, cross-level, elevation-arc, elevating-screw, vernier, focusing-collar, deflection-screw, deflection-scale, micrometer, disc, and telescope-level. (See Fig. 68.)
THE TELESCOPIC SIGHT
MODEL 1898.
Fig. 68.
Q. How is deflection set on it?
A. By moving the deflection-screw the vertical cross-wire moves.
Q. How is deflection set to fire right and to fire left?
A. Move the vertical hair to the right to fire left, move it to the left to fire right, by turning the deflection-screw.
Q. How is elevation set on it?
A. Set the zero of the vernier opposite the mark on the limb representing the number of even degrees of the given elevation. Then turn the micrometer-disc by turning the elevation-screw until the given number of minutes is read on it. The sight is then set on the trunnion-bracket and the piece elevated till the bubble comes in the middle for quadrant elevation or till the horizontal cross-hair cuts the water line of target for sight elevation. The gun then has the elevation set on the sight.
Q. What is the lowest reading of the vernier on the elevation-arc?
A. Two minutes.
Q. What is the lowest reading of the deflection-scale?
A. Three minutes.
Q. Why is it necessary to elevate the gun till the bubble on the telescope-level comes in the middle, to set the gun for quadrant elevation?
A. Because by definition quadrant elevation is the angle between the axis of the bore and the horizontal plane, and when the bubble is in the center of the level the telescope is horizontal and the axis of the gun makes an angle with it equal to the elevation set on the arc.
Q. Name and point out the following parts of the rapid-fire sight: Telescope, objective, eyepiece, interior and exterior deflection-scales, micrometer-head, deflection-screw, open sights, dew-cap, lugs, and thumb-screws.
A. See Fig. 70.
Q. What is one point on the deflection-scale equal to at the target?
A. One five-hundredth of the range in yards; thus one point equals 2 yards at 1000 yards, 4 yards at 2000 yards, and so on.
Q. Example: The range is 5000 yards, and the drift for that range is found in the range-table to be 12 minutes; how would you set your deflection-scale on the telescopic sight?
A. "Fire left" 12 minutes, or 4 points.
Q. Why?
A. Because drift in our service is always to the right, and to overcome this drift and make the projectile hit the target we will have to fire to the left this 12 minutes due to drift.
Q. Example: The range is 5000 yards, and the component of the wind perpendicular to the line of fire is 20 miles, giving from the range-table correction for drift equal to 12 minutes and wind 6 minutes. The wind is blowing from right to left. How would you set your sight?
A. "Fire left" 6 minutes.
Q. Why?
A. Because, as shown above, the drift alone would require the sight to be set at "Fire left" 12 minutes, and if the wind correction is 6 minutes and is blowing from right to left, to overcome this wind and make the projectile hit the target we would have to "Fire right" 6 minutes. Therefore, if the total setting of the sight is to be "Fire left" 12 minutes plus "Fire right" 6 minutes, the final or resultant setting should be "Fire left" 6 minutes.
Note.—The corrections for wind and drift are usually found at the same time from a chart, correction-board, or table.
Q. Example: The time of flight is 10 seconds (this is found from the gun commander's range-table, knowing the range); how would you determine the correction for travel with a telescopic sight?
A. Set the sight at zero. Traverse the gun until the vertical hair cuts the target. Signal: "Stop traversing," and count the number of seconds time of flight (10), moving by the right hand the deflection-screw, to keep the vertical hair on the target. When 10 seconds are counted stop turning the deflection-screw. Where the vertical hair now rests is the correction for "travel during time of flight." Since to "Fire left" we move the vertical hair to the right, this correction for travel found will have to be set for "Fire left," or on the other side of the scale, if the target is moving from right to left. If it is moving from left to right, the correction found will have to be set "Fire right." In other words, always set the cross-hair in the opposite direction from the motion of the vessel in making the correction for travel. This also applies to open sights.
Q. Example: If you were given the range, a gun commander's range-table, a correction for wind and drift equal to "Fire left" 9 minutes, and the target were moving from right to left, how would you proceed to determine the setting of your sight?
A. First, determine by the above method the correction for travel during time of flight (time of flight being found in the gun commander's range-table). Set this on the sight. Suppose it were "Fire left" 3 minutes.
Second, use this position of the vertical hair as a new zero, and move the vertical hair to "Fire left" 12 minutes. That is, "Fire left" 3 minutes plus "Fire left" 9 minutes equals "Fire left" 12 minutes.
If the travel had been "Fire right" 3 minutes, then by moving the scale "Fire left" 9 minutes, the final setting of the sight would have been "Fire left" 6 minutes.
Q. From the table on page 129 find the number of yards 3 points on the telescopic sight are equal to at 7000 yards range.
A. 18 yards.
TELESCOPIC SIGHT. (Model 1898.)
Fig. 69.
3-INCH RAPID-FIRE GUN-SIGHT.
Fig. 70.
2. Point or describe the location of the following parts of the telescopic sights, Model 1904:
Eye-lens cover.
Dial.
Focusing ring.
Peep-sight.
Eye-end telescope clamp.
Deflection worm knob.
Telescope tube.
Elevation rack.
Cell-end telescope clamp.
Objective shutter.
Cradle.
Cross sight.
Yoke-cap.
Deflection-pointer bracket.
Fulcrum.
Elevating wheel and hub.
Sight-bracket.
Plug connection for lamps.
Lamp-holder for deflection scale.
Range drum.
Gear-case cover and cover for range drum.
Telescope lamp-holder.
Sight-shank elevation-scale.
Elevation-guide.
Sight-arm.
Yoke-shaft.
Bearing for yoke.
Yoke.
Lamp-bracket for range drum and elevation-scale.
Elevation worm.
Focusing sleeve nut.
Deflection scale.
Elevating gear-shaft.
Deflection worm.
Eye-lens.
Field lens.
Cross-wire ring.
Cross wires.
Erecting prisms (Porro).
Objective.
A. See Figs. 71 and 72.
Fig. 71.
3-INCH TELESCOPIC SIGHT, MODEL OF 1904.
Fig. 72.
3-INCH TELESCOPIC SIGHT, MODEL OF 1904.
Table of Values in Yards of Points of Deflection.
| Min. | 3 | 6 | 9 | 12 | 15 |
| Points. | 1 | 2 | 3 | 4 | 5 |
| Range. | Value of Points in Yards. | ||||
| 1000 | 1 | 2 | 3 | 4 | 5 |
| 2000 | 2 | 4 | 6 | 8 | 10 |
| 3000 | 3 | 6 | 9 | 12 | 15 |
| 4000 | 3 | 6 | 9 | 12 | 15 |
| 5000 | 4 | 8 | 12 | 16 | 20 |
| 6000 | 5 | 10 | 15 | 20 | 25 |
| 7000 | 6 | 12 | 18 | 24 | 30 |
| 8000 | 7 | 14 | 21 | 28 | 35 |
| 9000 | 8 | 16 | 24 | 32 | 40 |
| 10000 | 9 | 18 | 27 | 36 | 45 |
Note.—This table is only approximate. It is true within 1 yard, which is sufficiently accurate for all firing under Case II.
Q. Where is the sight placed under cases one, two, and three?
A. On the trunnion for case one, to give both elevation and direction. On the sight standard for case two, to give direction only (quadrant elevation is set by the elevating-arc). It is not intended to be used at all in case three, but, of course, it could where the quadrant elevation is to be set by the sight instead of by the elevation-arc. It will then have to be placed on the trunnions.
Q. Define cases one, two, and three.
A. Case one, where direction and elevation are given by the sight on the trunnion. Case two, where direction is given by the sight, and elevation by the quadrant or elevating-arc. Case three, where direction is given by the azimuth-circle, and elevation by the quadrant or arc.
Q. What is the difference between the axis of the bore and the line of departure?
A. The jump. (See Fig. 63.)
Q. What is the line of sight?
A. Line joining the target, the point of the front sight and the peep of the rear sight; or with telescopic sights, the line joining the target and the intersection of the vertical and horizontal hairs in the sight. (See Fig. 63.)
Q. Define time of flight.
A. The time it takes the projectile to leave the bore till it strikes.
Q. What is a tangent?
A. A straight line which touches but one point on the circumference of a circle and is perpendicular to the radius at that point.
Q. Define angle of fall.
A. It is the angle which the tangent to the trajectory at the point of impact makes with a line parallel to the line of sight at this point.
Q. What is the line of departure?
A. The prolonged axis of the bore at the moment the projectile leaves the muzzle.
Q. What is the line of fire?
A. The prolonged axis of the bore before the gun is fired.
Q. What is the axis of the bore?
A. The line passing through the centre of the bore from breech to muzzle.
Q. What is the angle of departure?
A. The angle included between the line of departure and the horizontal plane.
Q. Define drift.
A. It is the deviation due to the rifling in the gun to the right or left of the vertical plane passing through the axis of the bore, or plane of fire. It is always to the right in the U. S. service.
Q. To what in a telescopic sight does the front sight on an open sight correspond?
A. The intersection of the cross-hairs.
Q. To what does the rear sight correspond?
A. The eye-lens.
Q. What is the trajectory?
A. The path of the projectile in the air.
Q. How is the velocity of the wind determined?
A. By the anemometer. First take the reading of the discs on the anemometer and note the time. After six minutes have elapsed read the scales. Take the difference of the scales and multiply by 10, which gives the velocity. (See Fig. 73.)
For example: Suppose at 10:05 A.M. the reading is 62 miles, and at 10:11 A.M. the reading is 63 miles. If in six minutes it goes one mile, in sixty minutes it will go ten times, or ten miles per hour.
THE ANEMOMETER.
Fig. 73.
Q. How are the components of the wind in the direction of the line of fire and in a lateral direction determined? (See Fig. 74.)
A. First: Set the arrow on the disc to read the azimuth of the wind. (This is done automatically.)
Second: Set the little lever-arm at the azimuth of the line of fire.
Third: At the point on the lever-arm reading the velocity of the wind as determined by the anemometer, run the finger or a pencil along the nearest line toward the arrow, and where this line cuts the arrow is read the longitudinal component or the component in the direction of the line of fire.
Fig. 74.
Q. How are the wind components determined by the "new method"?
A. 1o target-pointer to velocity of wind on target-arm.
2o Set ring to azimuth of wind.
3o Set target-arm to azimuth of gun.
4o Components are now read on the dial from the point indicated
by the target-pointer. (See Fig. 75.)
WIND COMPONENT. (New Method.)
Fig. 75.
THE AEROSCOPE.
Fig. 76.
DIFFERENCE CHART
for
10 in. B.L.R. No.1
in Battery __________, Fort __________
Directing Gun of that Battery
10 in. B.L.R. No.2
Azimuth of Gun No.1 from Directing
Gun, 79°03'
Gun Displacement, 38 Yards.
Fig. 77.
Fourth: From this same point on the little lever-arm run a pencil along the nearest line parallel to the arrow, and where it intersects the diameter of the disc perpendicular to the arrow is read the component in the direction of deflection or the lateral component.
Q. What is a difference chart?
A. One that determines the differences in azimuth and range between the directing-gun and the gun for which it is constructed. It consists of a board having drawn on it circles of different diameters, which are the azimuth difference circles (the amounts being written on each circle). (See Fig. 77.)
Q. How is it used?
A. First: Set the range-arm on the given azimuth.
Second: Run the finger to the given range on the range-arm.
Third: The azimuth difference is read on the nearest circle that cuts the point where the finger last rests, and the range difference is read on the scale in red ink along the azimuth circle of the board. (See Fig. 77.)
Q. What is meant by muzzle velocity?
A. The number of feet per second a projectile is moving at the time it leaves the muzzle of the gun. It is also called Initial Velocity.
Q. From the following gun commanders' range-scale find the time of flight, sight elevation, and quadrant elevation for 4120 yards range.
Gun Commanders' Range-scale.
I. V. 2200. 8-inch B. L. R. Smokeless powder.
| Quadrant Elevation. | Range | Sight Elevation. | Time of Flight, | ||
| Degrees. | Minutes. | Degrees. | Minutes. | Seconds. | |
| +4 | 16 | 4100 | -1 | 3 | 6-1/5 |
| +4 | 18 | 4120 | -1 | 1 | |
| +4 | 20 | 4140 | -0 | 58 | |
| +4 | 23 | 4160 | -0 | 56 | 7-2/5 |
| +4 | 26 | 4180 | -0 | 54 | |
| +4 | 28 | 4200 | -0 | 51 | |
| +4 | 31 | 4220 | -0 | 49 | 8-2/5 |
ELECTRICAL DEVICE FOR OPERATING ANEMOMETER STOP-WATCH.
Fig. 78.
A. 6-1/5 seconds, about; 1° 1' minus (depression); 4° 18' plus (elevation).
The Atmosphere-board.
Q. Describe the atmosphere-board.
A. This is merely a graphic table by means of which the reference-numbers to be recorded on the atmosphere-aeroscope indicator can be determined from the readings of the barometer and thermometer. The arguments are barometer and thermometer readings, and the reference-numbers are indicated by diagonal lines. The thermometer axis is horizontal and the barometer axis is vertical. To increase the ease and rapidity of reading the barometer scale is graduated on a movable T square.
The method of construction is shown in Fig. 79.
Operation.—Set the T square for the thermometer reading and note the diagonal line which intersects the fiducial edge of the T square the nearest to the barometer reading. The atmosphere dial is graduated to ½ per cent. The reading of the board should be taken to the nearest half reference-number.
ATMOSPHERE BOARD
Fig. 79.
SPECIAL APPARATUS FOR MORTARS.
Q. Point to the following parts of the Mortar Gun-arm:
Movable gun-arm.
Yards range.
Overlap.
Elevations.
Time of flight.
Zones.
A. See Fig. 80.
SET-FORWARD RULER.
Q. Describe the set-forward ruler and explain its use.
A. First find the travel in yards per minute. Set the pointer (a) on the slide (b) at the number of yards on the scale of "yards travel per minute (c)." Then on gun-arm get time of flight for that point. The "set-forward point" will be the reading opposite time of flight on the scale of "yards travel during time of flight +1 minute (d)." (See Fig. 81.)
Example.—After taking four observations on a target we find that in one minute's time it has traveled 200 yards. Set the pointer (a) at 200 yards on the scale (c). On the gun-arm we see that the time of flight for this point is sixty seconds. Therefore our set-forward point is 400 yards, as this is the reading exactly opposite the time of flight on scale (d). (See Fig. 81.)
Q. Describe and explain the use of the prediction scale.
A. The prediction scale is graduated in the same manner as the gun-arm (1" = 300 yards), and is used for finding the predicted point. After having marked four points on the board, showing the course of the target, place the prediction scale so that zero (0) is on the last point, or reading, and then mark off as many yards in advance of the last point as the first reads from zero. This point is known as the predicted point, and is used by the range officer only. As soon as the predicted point is found he sets his azimuth instrument at the given azimuth and when the target crosses the vertical wire in the instrument, he gives the signal "Fire." (See Fig. 82.)
GUN ARM FOR MORTARS.
Fig. 80.
Fig. 81.
THE SET FORWARD RULER FOR MORTARS.
Fig. 82.
THE PREDICTION SCALE.
DEFLECTION SCALE.
Q. Describe the deflection scale and explain its use.
A. The deflection scale is used to determine azimuth corrections for mortars. After the "set-forward point" has been obtained, the plotter sets the gun-arm on it and by means of the indicator determines the zone, range, and elevation of the target. The operator reads the straight azimuth from the gun-azimuth scale and gets the zone and elevation from the plotter. He then sets the elevation scale-pointer at the given elevation, turns crank moving small azimuth pointer to the azimuth he obtained from gun-arm scale; then by referring to the large azimuth scale-pointer he reads the corrected gun-azimuth, which he sends to the pits together with zone and elevation. Should it become necessary to make a correction for drift, turn the deflection-scale knob, either to right or left, as the case may be, as 3 = normal. (See Fig. 83.)
Note.—This apparatus depends upon the fact that the drift is the same for the same elevation in every zone except the eighth. In this zone the instrument cannot be used as now constructed.
WARSHIPS.
Q. State the general appearance, average length, beam, draft, speed, tonnage, thickness of belt and deck armor of battleships, armored cruisers, protected cruisers, torpedo-boat destroyers, and torpedo boats.
A. See Table "A."
Q. Point from Figs. 84 and 85 the following:
Sloop.
Schooner.
Ship.
Bark.
Barkentine.
Brig.
Brigantine.
Steam yacht.
Revenue cutter.
Gunboat.
Protected cruiser.
Armored cruiser.
Battleship.
Torpedo-boat destroyer.
Torpedo boat.
Submarine.
Monitor.
Fig. 83.
THE MORTAR DEFLECTION SCALE.
TABLE A.--TABLE OF WARSHIP CHARACTERISTICS.
| Characteristics. | Battleships. | Armored | |
| Cruisers. | |||
| Large, massive | High freeboard, | ||
| appearance, | fine | ||
| low freeboard, | lines, fairly | ||
| General Appearance. | large, turrets, | heavy guns | |
| heavy | and turrets, | ||
| guns, heavy | great | ||
| armor, | length as | ||
| moderate | compared | ||
| speed. | to beam, | ||
| high speed. | |||
| Average length | 400 feet | 500 feet | |
| Average beam | 75 feet | 67 feet | |
| Average draft | 29 feet | 28 feet | |
| Average speed | 17 knots | 21 knots | |
| Average tonnage | 15,000 tons | 11,000 tons | |
| Aver. thickness, belt armor | 13 inches | 5 inches | |
| Aver. thickness, deck armor | 3 inches | 3-1/3 inches | |
| Torpedo | |||
| Characteristics. | Protected | Boat | Torpedo |
| Cruisers. | Destroyers. | Boats. | |
| High freeboard, | Very long, | Small size, | |
| moderate | narrow | long, | |
| size, very | beam, | narrow, | |
| General Appearance. | fine lines, | high | not as |
| light armament, | bow, low | many | |
| narrow | freeboard, | smokestacks | |
| beam. | many | as a | |
| smokestacks. | destroyer. | ||
| Average length | 350 feet | 250 feet | 175 feet |
| Average beam | 50 feet | ||
| Average draft | 22 feet | ||
| Average speed | 22 knots | 31 knots | 28 knots |
| Average tonnage | 5000 tons | 350 tons | 200 tons |
| Aver. thickness, belt armor | none | ||
| Aver. thickness, deck armor | Protective | ||
| deck 2 ins |
Q. What vessels are unarmored?
A. Gunboats, torpedo-boats and destroyers.
Q. What is the best part of a ship to attack at long range?
A. The decks.
Q. What part should rapid-fire guns attack at short range?
A. Sides, ends, and small turrets, and guns protected only with shields. These rules, however, may vary with height of battery, form of attack, and class of ships attacking.
Q. How are ships of the U. S. Navy distinguished, knowing their names? (See Fig. 86.)
A. Battle-ships are generally named after States (except the Kearsarge), cruisers after large cities, gunboats after historical cities as a rule, coast-defense monitors have Indian names, torpedo-boats and torpedo-boat destroyers are named after heroes of wars. (The above rules have a few exceptions.)
Q. From the silhouettes on Fig. 86, Ships of the U. S. Navy, find a battle-ship, a high-speed cruiser, a gunboat, a coast-defense monitor.
Fig. 84.
Fig. 85.
Fig. 86.
Signal
Number. Name.
1 Katahdin
2 Wilmington (2B Helena)
3 Terror
4 Amphitrite
5 Miantonomoh
6 Monterey
7 Puritan
8 Monadnock
9 Vesuvius
10 Buffalo
11 Castine (11B Machias)
12 Marietta (12B Wheeling)
13 Bancroft
14 Bennington (14B Concord, 14C Yorktown)
15 Isla de Cuba (15B Isla de Luzon)
16 Texas
17 Annapolis (17B Newport, 17C Princeton, 17D Vicksburg)
18 Dolphin
19 Petrel (19B Don Juan d'Austria)
20 Alabama (20B Illinois, 20C Wisconsin)
21 Iowa
22 Indiana (22B Massachusetts, 22C Oregon)
23 Nashville
24 Chattanooga (24B Cleveland, 24C Denver, 24D Des Moines,
24F Galveston, 24G Tacoma)
25 Marblehead (25B Detroit, 25C Montgomery)
26 Philadelphia
27 Minneapolis
28 Raleigh
30 Chicago
31 Newark (31B San Francisco)
32 Atlanta (32B Boston)
33 Kearsarge (33B Kentucky)
34 Baltimore
35 Albany
36 New Orleans
37 New York
38 Brooklyn
39 Columbia
A. Signal numbers 20, 30, 23, 6.
Q. Find from Figs. 86 to 93 inclusive, a battle-ship, cruiser, monitor, and gunboat of the navies of Germany, France, England, Japan, and Russia.
Fig. 87.
Q. What thickness of Krupp cemented armor will a six-inch gun penetrate at 5000 yards? An eight-inch gun? A ten-inch gun? A twelve-inch gun, model 1895? A twelve-inch, model 1900?
A. Six-inch penetrates 3 inches; eight-inch, 5 inches; ten-inch, 7 inches; twelve-inch '95, 10 inches; twelve-inch 1900, 12 inches. (See Armor-attack Sheet, Fig. 87.)
SILHOUETTES OF SHIPS OF RUSSIAN NAVY.
Fig. 88.
Signal Name.
Number.
1 Khrabry
2 Grosiastchy (2B Otvajny, 2C Gremiastchy)
3 Abrek
4 Possadnik class
5 Bobr
6 Giliak
7 Peter Veliky
8 Nachimoff
9 Spiridoff (9B Greig, 9C Lazareff, 9D Tchitchagoff)
10 Mandjur (10B Tchernomoretz, 10C Zapororozets, 10D Donetz)
11 Koreitz
12 Koubanetz (12B Uraletz, 12C Teretz)
13 Pamiat Merkuria (Euxine)
14 Strelok (class in order named)
15 Ekaterina II (15B Tchesma) (Euxine)
16 Sinop (16B Georgi Pobiedonosetz) (Euxine)
17 Lieut. Ilyin (Euxine)
18 Kapitän Saken (Euxine)
19 Dvenadsat Apostolof (Euxine)
20 Sissoi Veliky
21 Rostislav (Euxine)
22 Tri Svititelia (22B K. P. Tavritchesky) (Euxine)
23 Apraksin (23B Oushakoff, 23C Senyavin)
24 Poltava (24b Petropavlovsk, 24C Sevastopol)
25 Alexander II (25B Nikolai I)
26 Rynda (26B G. Edinburgski, 26C General Admiral, 26D Minin)
27 Rurik
28 Viestnik class
29 Korniloff
30 Vladimir Monomakh
31 Dmitri Donskoi
32 Navarin (twin funnels)
33 Svietiana
34 Bogatyr
35 Pallada (35B Aurora, 35C Diana)
36 Novik
37 Peresviet (37B Osliabia)
38 Pobieda
39 Retvisan
41 Variag
42 Bayan
43 Gromovoi (43B Rossia)
44 Askold
Note.—Some of these ships have been destroyed by the Japanese.
SILHOUETTES OF SHIPS OF GERMAN NAVY.
Fig. 89.
Signal Name.
Number.
1 Biene class
2 Bremse (2B Brummer)
3 Jagd (3B Wacht)
4 Siegfried class
5 Odin
6 Baiern (6B Baden, 6C Sachsen, 6D Würtemburg)
7 Hela
8 See Adler class
9 Geier
10 Buzzard, Falke, etc.
11 Meteor (11B Comet)
12 Oldenburg
13 Jaguaur (13B Iltis)
14 Tiger (14B Luchs)
15 Blitz (15B Pfeil)
16 Gazelle (16B Nymphe, 16C Niobe, 14D Ariadne, 16F Medusa,
16G Thetis, 16H Niobe)
17 Hagen (and others as reconstructed)
18 Aegir
19 Irene (19B Prinzess Wilhelm)
20 Kaiser Friedrich III
21 Kaiser Wilhelm II (21B K. Wilhelm der Grosse, 21C Barbarossa,
21D Karl der Grosse)
21f Wittelsbach class
22 Fürst Bismark
22b Prinz Heinrich
23 Brandenburg (23B Worth, 23c Weissembourg,
23D K. Friedrich Wilhelm)
24 Deutschland
25 Kaiser (25B K. Wilhelm)
26 Greif
27 Gefion
28 K. Augusta
29 Hertha (29B Hansa, 29C Vineta, 29D Freya, 29F Victoria Luise)
SILHOUETTES OF SHIPS OF FRENCH NAVY.
Fig. 90.
Fig. 91.
Signal Name.
Number.
1 Onandaga
2 Acheron (2B Cocyte, 2C Phlegeton, 2D Styx)
3 Flamme (3b Grenade)
4 Tonnant
5 Tréhouart
6 Tempête (6B Vengeur)
7 Fulminant
8 Tonnere
9 Furieux
10 Dragonne
11 Leger (11B Levrier)
12 Fusée (12B Mitraille)
13 Magenta
14 Formidable
15 Vauban
16 Duguesclin
17 Friedland
18 Baudin
19 Marceau
20 Neptune
21 Redoutable
22 Bombe (22B Coulverine, 22C Dague, 22D Fleche,
22F S. Barbe, 22G Lance, 22H Salve)
23 Wattignies (23B Fleurus, 23C Epervier, 23D Condor, 23F Vautour;
some of these liable to be without main mast)
24 Terrible (Requin transformé probably 24B)
25 Indomptable
26 Caïman
27 Hoche
28 Courbet
28b Dévastation
29 Duperré
30 Jémappes (30B Valmy)
31 Bouvines
32 Dunois
33 D'Iberville
34 Casablanca (34B Cassini)
35 Forbin (35B Coetlogon)
36 Sfax
37 Jean Bart
38 Alger (38B Isly)
39 Descartes (39B Pascal)
40 Catinat (40B Protet)
41 Suchet
42 Davout
43 Linois
44 Galilée (44B Lavoisier)
45 Henri IV
46 Brennus
47 Carnot
48 Charlemagne (48B St. Louis, 48C Gaulois)
48d Jena
49 Masséna
50 Bouvet
51 Charles Martel
52 Charner (52B Chanzy, 52C Bruix, 52D Latouche Tréville)
53 Dupuy de Lôme
54 Jauréguiberry
55 Troude (55B Cosmao, 55C Lalande)
56 Milan
57 Kersaint
58 Surcouf
59 D'Estrees (59B Infernet)
60 Foudre
61 D'Assass (61B Du Chayla, 61C Cassard, 61D Friant,
61F Chasseioup Laubat, 61G Bugceud)
62 Pothuau
63 Tage
64 D'Entrecasteaux
65 Cecille
66 Chateaurenault
67 J. de la Gravière
68 New armoured cruisers
69 Guichen
70 Jeanne d'Arc
SILHOUETTES OF SHIPS OF JAPANESE NAVY.
Fig. 92.
Signal Name.
Number.
1 Hei Yen
2 Sai Yen
3 Matsushima
4 Itsukushima (4B Hashidate)
5 Tatsuta
6 Tsukushi
7 Yayeyama
8 Maya (8B Atago, 8C Chiokai)
9 Akagi
10 Naniwa (10B Takachiho)
11 Takao
12 Fuso
13 Toyohaschi
14 Oshima
15 Hi Yei (15B Kongo) (Kongo has no chart-house)
15C (D and F) (Katsuragi class)
16 Chiyoda
17 Miyako
18 Chihaya
19 Akashi
20 Yoshino
21 Takasago
22 Kusagi (22B Chitose)
23 Suma
24 Idzumi
25 Akitsushima
26 Chin Yen
27 Fuji (27B Yashima)
28 Asama (28B Tokiwa)
29 Asahi
29B Mikasa
30 3400-ton cruisers
31 Azuma
32 Yakumo
33 Idzumo (33B Iwate)
34 Shikishima
35 Hatsuse
SILHOUETTES OF SHIPS OF ENGLISH NAVY.
Fig. 93.
Fig. 94.
Fig. 95.
Signal
Number. Name.
1 Polyphemus
2 Abyssinia (2B Magdala)
3 Glatton
4 Cyclops (4B Gorgon, 4C Hecate)
5 Conqueror (5B Hero)
6 Rupert
7 Hotspur
8 Rattlesnake
9 Blonde
10 Scout (10A Fearless)
11 Mersey (11B Severn, 11C Thames, 11D Forth)
12 Bramble class
13 Brisk (13B Mohawk)
14 Orion
15 Ajax (15B Agamemnon)
16 Colossus (16C Edinburgh)
17 Cockatrice or Goldfinch class
18 Nymphe (18B Buzzard, 18C Daphne, 18D Phoenix)
19 Basilisk (19B Beagle)
20 Icarus class (in order named)
21 Satellite class (in order named)
22 Archer (22C Cossack, 22D Tartar, 22F Racoon, 22G Porpoise)
23 Iron Duke class
25 Monarch
26 Trafalgar
27 Nile
28 Sanspareil
29 Barracouta (29B Blanche, 29C Barrosa)
30 Hood
31 Centurion (31B Barfleur)
32 Royal Sovereign (32B Empress of India, 32C Resolution, 32D Repulse,
32F Ramillies, 32G Revenge, 32H Royal Oak)
33 Renown
34 Majestic (34B Magnificent, 34C Mars, 34D Prince George, 34F Jupiter,
34G Illustrious, 34H Victorious)
35 Hannibal (35B Cæsar)
36 Imperieuse (36B Warspite)
37 Dreadnought (37B Devastation, 37C Thunderer)
38 Collingwood
39 Benbow
40 Rodney
41 Camperdown (41B Anson, 41C Howe)
42 Vulcan
43 Pallas (43B Pearl, 43C Philomel, 43D Phœbe
44 Melpomene
45 Apollo class (B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, X, Z)
46 Hermione class (46B Astræa, C, D, F, G, H, K)
47 Hawke (47B Edger, 47C Endymion, 47D Grafton, 47F Theseus,
47G St. George, 47H Gibraltar)
48 Crescent (48B Royal Arthur)
49 Sharpshooter
50 Seagull
51 Assaye class
52 Alarm class
53 Dryad class
54 Grasshopper (54B Spider)
55 Sandfly
56 Talbot
57 Pelorus class
58 Katoomba class
59 Marathon (59B Magicienne)
60 Medea (60B Medusa)
61 Temeraire
62 Blake (62B Blenheim)
64 Minerva (64B Diana, 64C Venus, 64D Juno, 64F Doris, 64G Eclipse,
64H Dido, 64J Isis)
65 Neptune
66 Inflexible (rig shown is not yet fitted)
67 Canopus (67B Goliath, 67C Ocean, 67D Glory, 67F Albion,
67G Vengeance)
68 Formidable (68B Implacable, 68C Irresistible, 68D London,
68F Bulwark, 68G Venerable)
69 Hercules
70 Sultan
71 Iris
72 Arethusa (72B Amphion)
73 Mercury
74 Leander (74B Phæton)
75 Alexandra
76 Superb
77 Barham (77B Bellona)
80 Speedy
81 Arrogant (81B Furious, 81C Gladiator, 81D Vindictive)
82 Hermes (82B Highflyer, 82C Hyacinth)
86 Diadem (86B Europa, 86C Niobe, 86D Andromeda, 86H Spartiate,
86J Amphitrite)
87 Ariadne (87B Argonaut, 87C Spartiate, 87D Amphitrite)
88 Cressy (88B Aboukir, 88C Hogue, 88D Sutlej, 88F Euryalus,
88G Bacchante)
90 Powerful (90B Terrible)
CODE FLAGS AND PENNANTS
INTERNATIONAL CODE OF SIGNALS
U.S. STORM SIGNALS
Flags 8 feet square. Pennants 5 feet hoist, 12 feet fly
U.S. WEATHER-BUREAU SIGNALS
Fig. 96.
[To face page 168.]
EXPLOSION OF A SUBMARINE MINE BY THE GUNNERS OF THE 54TH CO. C. A., FORT TOTTEN, N. Y.
(Observation Firing on a Miniature Battleship used as a Target.)
[To face page 169.]