Quindenary

[…] it and M. Hermite's form ; the latter is intrinsically a quinary group of triadic products, but such representation in the case of M. Joubert's form is purely conventional and confusing, it really being a single indecomposable quindenary product.

[…] or 44 in the quindenary scale.

Each number had two names: a vowel and a consonant, from which the Reader can already see that they did not use the decimal but the quindenary numerical system.