According to Gerhardt, the process of substitution consisted of the union of two residues to fo- m a unitary whole; these residues, previously termed " compound radicals," are atomic complexes which remain over from the interaction of two compounds.
Finally, we have the family Rhinocerotidae, which includes the existing representatives of the group. In this family the dentition has undergone considerable reduction, and may be represented inclusive of all the variations, by the formula i a or a m a The first upper incisor, whenpresent, has an 430r2; PP antero-posteriorly elongated crown, but the second is small; when fully developed, the lower canine is a large forwardly directed tusk-like tooth with sharp cutting-edges, and biting against the first upper incisor.
In the above discussion it has been supposed that the ruling is accurate, and we have seen that by increase of m a high resolving power is attainable with a moderate number of lines.
A ?- *(1 5 C 16C 2+ C 3) C1 +$(C i - C2) -lO(C 2 - C3) (v) m a multiple of 12.
Let M, and M a be those moments.