Penny Infrared Cells for Water Solutions Coin holden used by collectors are now often made with polyethylene linings instead of polystyrene, and this material. because of its few absorption bands in the infrared, is a superior support for aqueous solutions as well as other liquids. At about $1.50 per hundred these cells are nearly a penny apiece, and the size (2 X 2 in.) is just right for most commercial spectrophotometer cell holders. Against a reference cell composed of an empty coin holder (preferably nickel size) very good spectra can be obtained. Of mum, the sides of the cell should be taped and stapled to prevent leakage; the sample is introduced a t the top with a medicine dropper and the cell automatically squeezes it t o a fairly uniform film. J. P. Phllllm University of Louisville Louisville. KY 40292
740
Journal
of Chemical Education
