D. VAN NOSTRAND COMPANY'S 



No. 59. RAILROAD ECONOMICS; OR, NOTES, WITH COM- 

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No. 60. STRENGTH OF WROUGHT-IRON BRIDGE MEM- 



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No. 61. POTABLE WATER AND METHODS OF DETECT- 

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No. 6a. THE THEORY OF THE GAS-ENGiNE. By Dugald Clerk. 

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No. 63. HOUSE DRAINAGE AND SANITARY PLUMBING. 

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No. 65. POCKET LOGARITHMS TO FOUR PLACES OF DECI- 

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No. 66. DYNAMO-ELECTRIC MACHINERY. By S. P. Thompson. 

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No. 67. HYDRAULIC TABLES BASED ON " KUTTER'S 

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No. 68. STEAM-HEATING. By Robert Briggs. Third edition, revised, 

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No. 69. CHEMICAL PROBLEMS. By Prof. J. C. Foye. Fourth 

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No. 70. EXPLOSIVE MATERIALS. The Phenomena and Theories 

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No. 71. DYNAMIC ELECTRICITY. By John Hopkinson, J. N. 

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No. 72. TOPOGRAPHICAL SURVEYING. By George J. Specht, 

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No. 73. SYMBOLIC ALGEBRA ; OR, THE ALGEBRA OP 



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No. 74. TESTING MACHINES : THEIR HISTORY, CON- 

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No. 75. RECENT PROGRESS IN DYNAMO-ELECTRIC MA- 

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No. 76. MODERN REPRODUCTIVE GRAPHIC PROCESSES. 



By Lieut. James S. Pettit, U.S.A. 



No. 77. STADIA SURVEYING. The Theory of Stadia Measurements. 

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No. 78. THE STEAM-ENGINE INDICATOR, AND ITS USE. 

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No. 79. THE FIGURE OF THE EARTH. By Frank C. Roberts, C.E. 



No. 80. HEALTHY FOUNDATIONS FOR HOUSES. By Glenn 

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