Matters of Gravity: Dark Matter and the Cosmological Constant

We consider two problems that have vexed physicists for several decades -- dark matter and the cosmological constant. The problem has been that the former has not been detected while the latter gives a far higher value than detected by observation. We argue that a time varying gravitational constant obviates the former problem, while the latter problem can be circumvented by considering the average density of the universe.
Comment: 11 pages latex