The list includes age measurements carried out from December 1966 and November 1967. All samples both of archaeologic and geologic interest are drawn from Italian territory.
Chemical techniques have remained unchanged (Bella and Cortesi, 1960). Two counters have been used for dating: the 1st, of 1.5 L, already described (Bella and Cortesi, 1960; Alessio, Bella, and Cortesi, 1964), the 2nd, of 1 L, recently assembled, is identical to the previous 1 L counter (Alessio, Bella, and Cortesi, 1964), its anticoincidence system was realized by a plastic scintillator and photomultipliers. Background 6.15 ± 0.08 counts/min, counting rate for modern carbon 24.49 ±0.15 counts/min. Higher efficiency of electronic recording was obtained by reducing pulse length and by a few other changes. All samples are usually measured by both counters.
The errors quoted, as in previous measurements, are 1σ statistical error. Age has been calculated using Libby's half-life of 5568 ± 30 yr, with 1950 as the standard year of reference. As in all previous measurements, the same modern wood, grown near Rome between 1949 and 1953, has been taken as modern standard: its activity has once again been carefully checked and judged satisfactory.