CHEJMISTRY — RICHARDS. 223 



further exposition of this matter. Dr. Speyers also spent much time in recal- 

 culating and reducing to a consistent basis previous results concerning the 

 properties of many substances, thus laying the basis for further research and 

 comparison. 



(2) The Heats of Solution of Metals: 



Dr. T. Thorvaldson devoted the winter to the improvement of the thermo- 

 chemical technique involved in the solution of metals in acids, under the 

 author's direction. Last year, with the help of Dr. L. L. Burgess, it had been 

 shown that Thomsen's methods and theory were both essentially faulty, and 

 the way had been paved for further advance. A few remaining defects of 

 detail were eliminated during the present work. A full description of the 

 somewhat complicated devices employed will be published as soon as possible. 



(3) The Heat of Solution of Barium: 



In connection with the work of Dr. Thorvaldson, the study of the extremely 

 reactive metal barium was begun with the help of Dr. H. E. Bigelow. This 

 element presents a problem of unusual difficulty, because of the extraordinary 

 precautions needed to obtain it in a pure state. Finally, by repeated distilla- 

 tion, with the help of an electric furnace at 1200° in a very low vacuum and 

 with special precautions, it was possible to accomplish the result desired. 

 Suboxide and hydride are the two impurities most difficult to eHminate ; the 

 method of Guntz is not wholly adequate to effect their removal. The heat of 

 solution of the metal may now be determined with precision ; the importance 

 of this datum may be inferred from its place in the last diagram given in the 

 Faraday Lecture. 



(4) Heats of Neutralisation: 



The work on the heat of neutralization of acids and bases was continued 

 with the help of Dr. A. W. Rowe, other acids and bases being added to the 

 list. It is hoped that before the next report this work may appear in print. 



(5) Heats of Combustion of Organic Isomers: 



Previous work, carried out with the help of Drs. Henderson, Frevert, and 

 Jesse, had perfected the technique of thermo-chemical work with volatile 

 liquids, and opened the way for further careful investigation. This was 

 taken up during the past winter with the help of Dr. F. Barry. Residual 

 work in other lines prevented him from progressing far; but a number of 

 hydrocarbons of exceptional purity were prepared, and it is hoped that they 

 may be made the subject of thorough research during the coming winter. 



(6) The Atomic Weight of Silver: 



One point was avowedly left incomplete in the recent research of Richards 

 and Willard concerning the atomic weights of silver and lithium, namely, the 

 question as to whether or not fused lithium perchlorate still retains water 



