  We introduce a new class of simple Lie algebras $W(n,m)$ that generalize the
Witt algebra by using "exponential" functions, and also a subalgebra $W^*(n,m)$
thereof; and we show each derivation of $W^*(1,0)$ can be written as a sum of
an inner derivation and a scalar derivation. The Lie algebra $W(n,m)$ is
$Z$-graded and is infinite growth.
