tinued.

(k) 24-inch bar: Elastic limit 24,200 pounds per square inch; tensile strength 47,600 pounds per square inch.

(1) 24-inch bar: Elastic limit 23,600 pounds per square inch; tensile strength 47,000 pounds per square inch.

10. Set of turned cylinders of Tamaqua iron, tested to ascertain the proper form of test-piece. They are all from the same bar, and of various lengths, from 10 inches down to the groove form; they show a difference in tensile strength of nearly 16,000 pounds, between the average of the pieces above four diameters in length, and the groove form.

(a) 10-inch piece: tensile strength 54,888 pounds, seamy.

(b) 94-inch piece: tensile strength 55,288 pounds.

:

(c) 9-inch piece tensile strength 55,355 pounds.

(d) 84-inch piece: tensile strength 55,622 pounds.

(e) 74-inch piece: tensile strength 54,890 pounds, seamy.

(f) 7-inch piece: tensile strength 55,488 pounds.

(g) 6-inch piece: tensile strength

51,800 pounds, bad seam.

(h) 6-inch piece: tensile strength 55,418 pounds.

(j) 5-inch piece: tensile strength 55,333 pounds.

(k) 4-inch piece: tensile strength

55,887 pounds.

(1) 3 inch piece: tensile strength 55,482 pounds.

(m) 3-inch piece: tensile strength 56,190 pounds.

(n) 1-inch piece: tensile strength 58,933 pounds.

(0) inch piece: tensile strength

59,388 pounds.

(p) Groove piece: tensile strength 71,300 pounds.

rivet iron, illustrating the proportions of test-pieces to be used with a soft iron. In this set the average tensile strength of the pieces above five diameters in length was 46,000 pounds per square inch; that of the groove specimen, 61,000 pounds; a difference of 15,000 pounds per square inch.

(a) 8-inch piece: tensile strength 45,800 pounds.

(b) 7-inch piece: tensile strength 45,930 pounds.

(c) 6-inch piece: tensile strength 45,995 pounds.

(d) 5-inch piece: tensile strength 45,763 pounds.

(e) 4-inch piece: tensile strength 46,561 pounds.

(f) 3-inch piece: tensile strength 46,759 pounds.

(g) 2-inch piece: tensile strength 46,734 pounds.

(h) 1-inch piece: tensile strength 47,033 pounds.

(j) Groove piece: tensile strength 61,023 pounds.

12. Four pieces turned from a 2-inch bar of Catasauqua iron, and tested to ascertain the difference due to variation of the sectional area of the test-piece. The large pieces (1 inches in diameter) broke at 49,500 pounds per square inch, and the small ones ( inch in diameter) broke at 49,850 pounds per square inch.

13. Collection of cable links broken by tension, showing the different characters of breaks of iron suitable for chain cables.

14. Cable links broken by tension, showing iron unfit for chain cable.

15. Cylinder test-pieces, giving their shape before and after straining to tensile limit.

strength, but not suitable for stand

ing sudden shocks or to make chain cable.

CLASS A.-DRY DOCKS.

1. Model of dry-dock, U. S. navy-yard, Brooklyn, N. Y.

Commenced August, 1841; completed August, 1851; length, 350 feet; breadth, 66 feet; draft of water, 25 feet; capacity, 7,000 tons; material, granite; weight of turning gates, 187 tons; weight of caisson, 217 tons; cost of caisson, $79,500; cost of dock, including pumping 4. engine and caisson, $2,000,000. 2. Model of the stone dry-dock being constructed at the U. S. navy-yard, Mare Island, California. Principal dimensions: Extreme length of dock over all, 525 feet 9 inches; length of floor on line of keel blocks from inside of caisson, 440 feet; length on floor from face of invert to first altar, 418 feet; length of invert, 41 feet; length of invert and apron, 48 feet 9 inches; width of invert at coping, 78 feet; width of floor, 30 feet; inside width of dock at coping, 104 feet; depth of water on invert at mean high tide, 27 feet 6 inches; depth of water on floor at invert, 32 feet.

3. U. S. naval dry-dock at Norfolk, Va. Cost, $943,676.73. Dimensions: Extreme length at top, 322 feet; width at bottom, 30 feet; width at top, 86 feet; commenced December 1, 1827; John Q. Adams, Pres

ident of the United States; Samuel L. Southard, Secretary of the Navy. Authorized by the Nineteenth Congress. Opened June 17, 1833, Andrew Jackson, President of the United States; Levi Woodbury, Secretary of the Navy; Laomi Baldwin, engineer. Scale of model, 8 feet to 1 inch. Dry-dock, navy-yard, Boston. Commenced July 10, 1827; opened

June 24, 1833; cost, $677,090; lengthened 65 feet in 1857-'58-'59; extreme length on coping, 402.8 feet; width on coping, 99.7 feet; width of coping on main arch, 60 feet; depth from top of coping to floor of chamber at the head, 30.9 feet; depth from top of coping to floor of chamber at the galleries, 32 feet; length of floor of chamber, 293 feet.

Cumberland, 1825. Pennsylvania, 1822. Merrimac, 1855.

23. Model of torpedo boat (twin screws). 24. Model of torpedo boat (single screw). 25. Model of the U.S. ship Vandalia (sails). 26. Gig of the Lackawanna.

27. Model of the U. S. ship Constitution. 28. Model of the U. S. ship Mississippi, 1841.

29. Model of the U. S. ship Jamestown. 30. Model of the U. S. ship St. Mary's. 31. Model of the U. S. ship Portsmouth. 32. Model of a boat with Wood's gear for

lowering, hoisting, and securing boats, and apparatus for detaching and attaching them.

CLASS B.

1. Ship's knee, bent by bending machine. 2. Steam steering machine.

"Sickles's Steam Steering Apparatus consists simply of two ordinary steam cylinders, operating a linked chain leading directly to the tiller. The valve motion is operated by a hand-wheel or cord to control the movement of the rudder. This cord or hand-wheel ̧ may be placed at any convenient part of the vessel." (Appendix No. 25.)

3. Balsa with fitments complete.

CLASS C.-RELICS.

1. A fragment of the United States frigate

Philadelphia, Capt. Wm. Bainbridge, U. S. N., wrecked on the rocks, four or five miles to the eastward of Tripoli, Africa, November 1, 1803.

At 7 p. m., February 16, 1854, Lieut. Stephen Decatur, jr., commanding the ketch Intrepid, of four guns, with sixty-two men and the following officers, viz:

Lieut. STEPHEN DECATUR, Jr., commander. Lieutenants: James Lawrence, Joseph Bainbridge, Jonathan Thorn. Surgeon: Lewis Heerman. Midshipmen: Ralph Izard, John Rowe, Charles Morris, jr., Alexander Laws, John Davis, Thomas Macdonough, Thomas O.

1. A fragment of the United States frigate

Philadelphia Continued. Anderson. Pilot: Salvador Catoloni, entered the harbor of Tripoli, and boarded and took possession of the Philadelphia. At the time the Philadelphia was boarded, she had all her guns mounted and charged, and was lying within half gunshot of the Bashaw's castle and of its principal battery. Two Tripolitan cruisers were lying within two cables' length, with starboard quarters, and several gun-boats within half gunshot, with starboard bow; and all the batteries on shore were opened upon the assailants. About twenty men of the Philadelphia were killed; a large boat-full got off; many leaped into the water, and one man was made prisoner. After having gained possession of the frigate, Lieutenant Decatur set fire to the store-rooms, gun-room, cockpit, and berth-deck, and, with a firmness highly honorable to him, his officers, and men, they remained on board until the flames had issued from the ports of the gun-deck and the hatchways of the spar-deck; and they continued in the ketch alongside the frigate until the fire had communicated to the rigging and tops. Lieutenant Decatur did not lose a man, and had but one slightly wounded. (See The United States Naval Chronicle, by Charles W. Goldsborough, vol. i., pp. 250– 256.) This fragment was recovered and brought to the United States by Capt. Earl English, U. S. N., commanding the U. S. frigate Congress.

2. Piece of timber from the starboard bow of the U. S. ship Kearsarge.

3. Piece of wood from the bow of Commodore Perry's flagship Lawrence, showing where a 24-pound shot from the enemy's gun lodged, September 10, 1813.

longing to the outfit for 500 men. 11. Additional general operation case.

CLASS B.-SURGICAL APPLIANCES.

1. Outfit of medicines for 500 men, comprising 147 articles.

2. Cot for transporting wounded men on board ship.

3. Stretcher for transporting wounded

men.

4. Amputation table having a folding leaf, which allows it to be converted into a writing table.

CLASS C.-HOSPITAL STORES.

1. Hospital stores for 500 men.

2. Hospital furniture for a ship with 500

men.

the ship in hot weather.

2. Aërator for distilled water.

CLASS G.-PHOTOGRAPHS OF HOSPITALS. 1. U. S. Naval Hospital at Chelsea, Mass. 2. U. S. Naval Hospital at Brooklyn, N. Y. 3. U. S. Naval Hospital at Philadelphia. 4. U. S. Naval Asylum at Philadelphia. 5. U. S. Naval Hospital at Annapolis, Md. 6. U. S. Naval Hospital at Washington, D. C.

7. U. S. Naval Hospital at Norfolk, Va. 8. U. S. Naval Hospital at Mare Island, California.

9. Natianal Home for Disabled Volunteer Soldiers and Sailors.

CLASS H.-STATIONERY.

1. Surgeon's outfit of stationery.

men.

4. Elevating bedstead with movable footboard to adapt it for use as an ordinary fracture bedstead.

Set of record and account books for naval hospital.

3. Blank form for record of physical examinations of candidates for admission to the Naval Academy.