The Wealth of Kings

Well, hey--for years I've been looking for a source for the (?) story about the king whose wealth lay in decency, civility and good order of his people. I thought it might be in Herodotus, but better Greek minds than mine say they don't recognize it. I had more or less come to assume that I made it up myself. But then the other night I was fingering through an old Signet Paperback selection of Samuel Johnson and came upon this:

When in the diet of the German empire, as Camerarius relates, the princes were once displaying their felicity, and each boasting of the advantages of his own dominions, one who possessed a country not remarkable for the grandeur of its cities, or the fertility of its soil, rose to speak, and the rest listened between pity and contempt, till he declared, in honour of his territories, that he could travel through them without a guard, and if he was weary, sleep in safety upon the lap of the first man whom he should meet; a commendation which would have been ill exchanged for the boast of palaces, pastures or streams.

--Samuel Johnson, Rambler No. 79 [Suspicion]

Yep, search over. But now, what is the deal with "Camerarius"? I suppose a fully annotated Rambler might tell me, but I don't have one at hand. Google offers several possible candidates, but I suspect that this is the guy.

Update: Thanks to Chrismealy, infra, for making the perfectly obvious (but missed by me)suggestion of Google books. Sure enough, here's the Yale edition, with this footnote:

We have not found the story in Camerarius. But Johnson refers to the fifteenth-century Graf Eberhard im Bart--also the subject of the well-known German poem by Justinus Kerner. The Diet in question was probably that of Worms (1495), a year before Eberhard's death.

Sounds like game, set and match, Chrismealy. But what is this "we have not found" stuff? Were they looking in the wrong Camerarius?