| BUNSEN | Robert ___, 19th-century German chemist; co-discoverer of caesium and rubidium (6) |
| CAESURA | Unequal readings of caesium and uranium give you pause |
| LIEBIG | Justus ___, 19th-century German chemist who founded agricultural chemistry (6) |
| SECOND | Unit of time defined as "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom" (6) |
| REUTER | Paul ___, 19th-century German telegrapher who founded a news agency in London (6) |
| WATSON | Co-discoverer of the contents of the circled letters |
| BRAHMS | Johannes _, 19th-century German composer (6) |
| RAMSAY | The Gentle Shepherd author; his portraitist son; a co-discoverer of argon; or, a seven Michelin star chef (6) |
| CARBON | Element, rubidium, combined with oxygen inside container (6) |
| BERBER | North African putting rubidium in ale (6) |
| SCHUMANN | Robert _, 19th-century German romantic composer (8) |
| HOUR | Unit of time whose precision relies on the rhythm of caesium atoms, during which Earth turns 15Adegrees and 1/24th of a solar day passes (4) |
| BROWNING | Robert _, 19th-century English poet who wrote The Ring And The Book (8) |
| COHN | Ferdinand ___, 19th-century German botanist and biologist credited with founding the science of bacteriology (4) |
| BAEDEKER | Karl ___, 19th-century German publisher of a series of travel guidebooks |
| RUBIDIUM | Soft silvery-white element of the alkali metals group similar to caesium and potassium, atomic no. 37 (8) |
| ATOMICSECOND | Time interval defined in terms of caesium-133 radiation frequency |
| MOMMSEN | Theodor ___, 19th-century German historian noted for his History of Rome (7) |
| KRYPTON | Element between bromine and rubidium |
| RAYLEIGH | 3rd Baron -; title of John William Strutt, co-discoverer of argon who wrote The Theory of Sound (8) |
