Instruction and study (1) Employment (1) Chemical warfare (1) Assaying (1) Textbooks (1) Observations (1) Textbooks (1) Interviews (1) Observations (1) Laboratory manuals (1) Problems, exercises, etc (1) Teaching (1) Speeches, addresses, etc (1) Possibility (1) Maintenance (1) Learning (1) Interviewing in journalism (1) Grilles (1) Government etiquette (1) Chemists (1) Appraisers (1) Ability (1) Interviews (1) Technique (1) Analysis (1) Practice (1) Occupations (1) Students (1) Experiments (1) Químicos (1)