HISTORICAL,

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General Description of Early Designs,

Appointment of Harlem River Bridge Commissioners, Secretary, and Chief Engineer, .

Appointment of Board of Experts for Examination of Competitive Designs, Prize De-

signs, etc.,

Final Plans adopted for Proposals,.

Award of Contract,

GENERAL DESCRIPTION.

Location,

Dimensions,

Grades,

General Description of Erection, Plant, and Distribution of Materials,

MASONRY.

MATERIALS.

Caisson Foundation of Pier II., and Detailed Description of Caisson,

Material Excavated; Method of Rock Excavation, Rock Drill, Explosives, etc.,

Electric Light, Compressors, and Timber Used,

Foundation of Pier III.,

Foundations of Small Piers,

SUPERSTRUCTURE.

Description of Construction of Piers above Skew-backs,

Description of 60 ft. Arches, and of the Abutments,

Stairway, Cornice, Parapets, Centering, .

Roadway,

Drain-Pipes, Gas-Pipes,

Sidewalks,

METAL WORK.

The Steel Arches: Dimensions, Flange Plates, Web-Plate, Segments, Pins, Bearings,

Pedestals, and Bracing of Ribs,

Posts, Struts, Floor-Beams, and Flooring; Expansion Joint,.

COMPLETION OF BRIDGE, PAYMENTS TO CONTRACTORS, COST OF ENGIN-

EERING, ETC.,

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Computed Variation of Rise, Deformation of Arch, etc.,

Henri de Dion's Method of Computing Resistance and Deformation,

CONDENSED STATEMENT OF QUANTITIES AND COST OF THE PRINCIPAL

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ADDITIONAL PRICES UNDER SECOND SECTION OF CONTRACT,

SPECIFICATIONS FOR PAVING,

TABLE SHOWING DIAMOND DRILL BORINGS-PIERS II. AND III.,

RECORD OF SINKING CAISSON FOR PIER II., .

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PLATES.

I.-FRONTISPIECE. CENTRAL PIER.-Looking South.

II.-VIEW OF INTRADOS (from Pier II. to Pier I.).

III.-MAP OF UPPER PART OF NEW YORK CITY. Showing location of Washington Bridge
and other Bridges over the Harlem River.

IV. EARLY DESIGNS FOR HARLEM River BridGE (10 Engravings). NO. 1 TO 4, DE-
SIGNS BY W. J. MCALPINE; No. 5, DESIGN BY ALFRED P. BOLLER; No.
6, BY WILSON BROS.; No. 7, BY BUCK & MCNULTY; No. 8, BY UNION BRIDGE
Co.; No. 9, BY E. S. SHAW; No. 10, BY JULIUS W. ADAMS.

V. ELEVATIONS OF PRIZE Designs, by C. C. SCHNEIDER AND BY W. HILDENBRAND,
ELEVATION OF CONTRACT DRAWING, AND OF BRIDGE AS BUILT.

VI. THE WASHINGTON BRIDGE. General View from the South.

VII-VIEW FROM THE SOUTH-WEST (PART OF METAL ARCH).

VIII-BEARING OF STEEL ARCHES UPON PIER III.

IX.-VIEW OF ROADWAY. Looking West.

X.-GAS AND ELECTRIC LAMPS, AND PARAPETS OVER PIERS.

XI.-BALUSTRADE AND DETAILS.

XII. VIEW FROM THE NORTH-EAST.

XIII-CONTRACT DRAWINGS. SECTIONS OF ABUTMENTS AS PROPOSED; ELEVATION OF
PIER, PEDESTAL AND BEARING SUBMITTED BY PASSAIC ROLLING MILL CO.

XIV. STRAIN SHEETS SUBMITTED BY CONTRACTORS, WITH PROPOSALS.

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XVIII. PIER II. Sept. 8, 1887.

XIX.--PEDESTALS, PIER III. Sept. 8, 1887. BEARING OF STEEL ARCHES, PIER III.; RIVETING MACHINE AT WORK.

XX.-WEST SIDE. Nov. 4, 1887.

XXI.-WEST SIDE. Looking North-East-Nov. 4, 1887-showing Centering.

XXII. Two VIEWS-PIER II., LAND SPAN, AND EAST SIDE. Nov. 4, 1887.
XXIII.

THREE VIEWS-WEST SIDE, LAND SPAN, AND EAST SIDE. Dec. 24, 1887.

XXIV.-WEST SIDE. March 23, 1888.

XXV.—RIVER SPAN. March 23, 1888 (False Works of River Span).

XXVI.-TWO VIEWS-RIVER AND LAND SPANS, AND EAST SIDE. March 23, 1888.

XXVII.-Two VIEWS--FLOOR-BEAMS AND BUCKLE PLATES. May 7 and May 18, 1888.
XXVIII.--TWO GENERAL VIEWS OF BRIDGE, April 6 and August 24, 1888.

XXIX.-LAND AND RIVER SPANS. August 24, 1888.

XXX.--STAIRWAY. August 24, 1888.

XXXI.-THREE VIEWS--WEST SIDE, LAND SPAN, AND EAST SIDE. Nov. 1, 1888.

XXXII-GENERAL ELEVATION AND PLAN OF WASHINGTON BRIDGE, Scale 60 feet to inch.

PLATES.

SERIES OF PLATES SHOWING MASONRY WORK.

XXXIII.-DETAIL PLANS OF CAISSON FOUNDATION OF PIER II.

XXXIV. METHOD OF ROCK EXCAVATION IN CAISSON.

XXXV.-ELEVATION OF PIER I., WEST ABUTMENT AND APPROACH AND PART PLAN.
XXXVI.-ELEVATIONS OF PIER II. AND PLANS.

XXXVII.-SECTIONS OF PIER II. AND PLANS.

XXXVIII.-ELEVATION OF PIER III. EAST ABUTMENT AND APPROACH AND PART PLAN.
XXXIX.-SECTIONS OF PIER III. EAST ABUTMENT AND APPROACH, AND PLAN.

XL.-DETAILS OF MASONRY, MAIN CORNICE AND PARAPET ON ABUTMENTS AND
PIERS. SKEW-BACK AND LOWER CORNICE.

XLI.-DETAILS OF MASONRY. INTERIORS OF PARAPET OVER PIERS AND SECTIONS OF
PARAPET OVER PIERS, ABUTMENT, AND APPROACH, ETC.

XLII.-JOINING OF MASONRY AND METAL WORK AT FLOOR LEVEL.

XLIII. CENTRES FOR LARGE MASONRY ARCHES.

SERIES OF PLATES SHOWING METAL WORK.

XLIV.--LONGITUDINAL SECTION ON CENTRE LINE OF ONE ARCH. (ELEVATION OF INNER

RIB.)

XLV. SECTION THROUGH PANEL 4 OF STEEL ARCH, SHOWING ALSO ROADWAY.

XLVI. PEDESTAL AND FIRST SEGMENT OF STEEL ARCH. SKEW-BACK, FLANGE OF FIRST
SEGMENT, EXPANSION BOLT, ETC.

XLVII. INTERMEDIATE SEGMENT (No. 5).

XLVIII.-JOINT of Segments of STEEL ARCHES. SECTION OF FLANGE.

XLIX. LATERAL BRACING BETWEEN RIBS.

L.-SECTIONS OF METAL STRUCTURE TO SHOW GENERAL ARRANGEMENT.
LI-POSTS AND STRUTS.

LII. TRANSVERSE FLOOR-BEAMS.

LIII. BUCKLE PLATES AND FLOORING.

V LIV. ANCHORAGE OF METAL Floor to MASONRY AND EXPANSION JOINT.

V LV. DETAILS OF CONNECTION OF METAL WORK AND MASONRY; EXPANSION
THROUGH; SLIDING AND PIER BEAMS; PLATE OVER SIDEWALK.

LVI-FALSE WORKS FOR EACH METAL SPAN.

LVII-SECTION OF IRON CORNICE AND BALUSTRADE.

} LVIII. ELEVATION OF IRON CORNICE AND BALUSTRADE.

LIX. ERECTION PLANT AND LOCATION PLANS, GENERAL ELEVATION AND PLAN.
LX.-DETAILS OF ERECTION PLANT. DERRICKS, FLOOR-TRAVELER, ETC.
LXI.--DETAILS OF ERECTION PLANT. DERRICKS, CONCRETE-MIXER, ETC.

LXII. DE DION'S METHOD FOR DEFLECTIONS.

LXIII.-ELEVATIONS OF EXISTING METAL ARCH BRIDGES OF OVER 500 FEET SPAN:
1. Bridge of Luiz I., over the Douro River, Portugal. 2. Garabit Viaduct, over the
Truyère River, France. 3. Pia Maria Bridge, over the Douro River, Portu-
gal. 4. St. Louis Bridge, over the Mississippi River, U. S. 5. Washington
Bridge, over the Harlem River, New York, U. S.

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