A simplified sink-float apparatus and method for measuring the densities of lumps of glass are described. Several lumps, of approximately two grams weight, of unknown density and one lump of glass of known density are placed in a heavy-liquids mixture contained in a test tube. The tube is immersed in a water bath that is heated automatically at a uniform rate; as the lumps settle, the temperature is noted at which each lump passes a reference line marked on the tube. The density of each unknown may be expressed simply in terms of the differences between its temperature and that for the stanard lump, or these temperature differences can be converted to density differences or to absolute densities. The precision (reproducibility) of the measurements is represented by a standard deviation of approx. 0.0001gm. per cc.
