This paper collects some important formulas on hyperbolic volume. To determine concrete values of volume function of polyhedra is a very hard question requiring the knowledge of various methods. Our goal is to give (in Section 3.3, Theorem 1) a new non-elementary integral on the volume of the orthoscheme (to obtain it without the Lobachevsky-Schläfli differential formula), using edge-lengthes as the only parameters.