Juvenile literature 665 Science 220 Mathematics 182 Problems, exercises, etc 108 Experiments 67 Animals 62 Study and teaching 59 Physics 58 History 57 Astronomy 54 Statistics 53 Examinations, questions, etc 50 Study and teaching (Secondary) 50 Chemistry 48 Plants 39 Biology 34 Biography 33 Miscellanea 33 Dictionaries 32 Algebra 30 Botany 29 Earth sciences 29 Pictorial works 29 Statistical methods 29 Birds 28 Natural history 26 Technology 26 Earth 25 Weather 25 Mathematical statistics 24