Juvenile literature 599 Science 209 Mathematics 175 Problems, exercises, etc 102 Experiments 64 Animals 58 Study and teaching 56 Physics 55 History 52 Astronomy 51 Study and teaching (Secondary) 50 Examinations, questions, etc 48 Statistics 48 Chemistry 46 Plants 33 Biology 32 Miscellanea 32 Dictionaries 31 Earth sciences 28 Pictorial works 28 Birds 27 Statistical methods 27 Botany 26 Technology 26 Algebra 25 Natural history 25 Biography 24 Weather 24 Mathematical statistics 22 Thesis 22