What is the origin of the Five Enobling Virtues?

> "The practice of precepts helps one to cultivate five ennobling virtues which correspond to each of the precepts. The first is the cultivation of compassion; the second, generosity and non-attachment; the third, contentment; the fourth truthfulness; and the fifth, mindfulness and clarity of the mind." I found this quote with a reference to *The Five Precepts and the Five Ennoblers (pañcasīla-pañcadhamma)* by Prince Vajirañāṇavarorasa -- but I can't locate the text anywhere or find anything about it. Can any one shed some light on this?