Subject
- Power resources1
- Priestley, Joseph, 1733-18041
- Rabies--Vaccination1
- Radar1
- Radium--Therapeutic use1
- Red Cross and Red Crescent1
- Rhazes1
- Río, Andrés Manuel del, 1764-18491
- Rockets (Aeronautics)1
- Romania1
- Ross, Ronald, Sir, 1857-19321
- Rubber plants1
- Rutherford, Ernest, 1871-19371
- Sabatier, Paul, 1858-19281
- Saint Kitts and Nevis1
- Sainte-Claire Deville, Henri, 1818-18811
- Salt springs1
- San Marino1
- Sapodilla1
- Science--Societies, etc.1