It could work that way if there was a convenient way to count 6.02 x 10^23 atom, or 6.02 x 10^23 of anything. -- ************************** Scott B. Webb, RSO Colorado State University Environmental Health Serv Fort Collins, CO 80523-6021 970-491-4835 F:970-491-4804 swebb@lamar.colostate.edu **************************