History 1,967 Politics and government 643 African Americans 304 Geology 292 Slavery 260 Law 227 Law and legislation 191 Social conditions 191 Education 189 Canals 182 Roads 182 Housing 172 Description and travel 166 Maps 162 Claims 161 Agriculture 158 Groundwater 158 Railroads 149 Slaves 149 Flood insurance 148 Research 135 Finance 134 Registers of births, etc 133 Statistics 133 Economic conditions 129 Songs (Medium voice) with piano 118 Church history 117 Cost 114 Water quality 113 Environmental aspects 110 Navigation improvements 110 Rivers, creeks, streams, etc 108 Legislative journals 105 Water-supply 105 Population 103 Race relations 103 City planning 99 Regional planning 97 Speeches, addresses, etc., American 95 Taxation 95 Historic sites 92 Fugitive slaves 91 Hydrographic surveying 91 Drama 89 Social life and customs 88 United States 88 Boundaries 86 Legislative amendments 86 Historic buildings 84 Study and teaching 84 Genealogy 80 Periodicals 80 Police 79 Women 79 Antietam, Battle of, Md., 1862 77 Theaters 77 Biography 74 Stationery 74 Antislavery movements 72 Channels (Hydraulic engineering) 72 Sources 72 Geology, Stratigraphic 71 Soils 71 Indians of North America 70 Elections 69 Militia 69 Curricula 68 Finance, Public 68 Legislative resolutions 68 Murder 66 Paleontology 66 Water 66 Banks and banking 65 Fiction 64 Campaigns 63 Economic aspects 63 Riots 63 Art 62 Mines and mineral resources 62 Pollution 62 Wills 62 Federal-state relations 61 Songs with piano 61 Law reports, digests, etc 60 State laws 60 Buildings, structures, etc 59 Families 58 Plantation life 58 Antiquities 57 Dredging 57 Real property 57 Stream measurements 57 Transportation 57 Archives 56 Medicine 56 Water resources development 56 Architecture 55 General 55 Jews 55 Societies, etc 55