In the course of certain research work it became necessary to measure the specific heat of liquid cis and trans decahydrate with great accuracy; The ordinary Williams and Danielle adiabatic calorimeter was found to be impractical* Several years ago a calorimeter for measuring the specific heat of liquid hydrocarbons near room temperatures was developed at the U.S. Bureau of Standards, A study of this instrument proved that it would be the type desirable for the above measurement. Plans were obtained and altered to suit not only the measurements for cis and trans decalin but such hydrocarbons as are solid at room temperatures. During the past year such a calorimeter was constructed. It has also been so altered as to permit measurements of the latent heat of fusion to be made with 1 part in 1000. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate