July 3, 1896,] 



SCIENCE. 



27 



It is noticeable that Prof. Tliomsen's density 

 of hydrogen is higher than that of Prof. Morley, 

 while his ratio for the atomic weights is lower. 

 This seems to indicate that the hydrogen ob- 

 tained by Prof. Thomsen was contaminated with 

 a trifling amount of some impurity. From the 

 experiments of Prof. Morley it seems probable 

 that hydrogen evolved by the solution of alu- 

 minium in potassium hydroxide containing a 

 small amount of the carbonate would contain 

 carbon. As no account is given in the paper of 

 any attempt to exclude the presence of potas- 

 sium carbonate, or if any experiments to prove 

 the absence of compounds of carbon or of 

 other impurities in the hydrogen used, it is, at 

 least, possible that the difference in the results 

 of the two workers is due to this cause. 



To one familiar with the character of such 



work it is rather a matter of suprise that the 



difference is not greater. 



W. A. ISToYES. 



A Dictionary of Chemical Solubilities, Inorganic. 



By Arthur Messinger Comey, Ph. D. 



8mo. Pp. 515. London and New York, 



Macmillan & Co., 1896. 



The attempt is made in this book to give re- 

 liable data concerning the solubility of all in- 

 organic substances that had been analyzed be- 

 fore March, 1894. 



"The solubility of the substance in water is 

 first given, the data being arranged chronologi- 

 cally in the longer articles. Then follow 

 the specific gravities of the aqueous solutions, 

 and also any data obtainable regarding their 

 boiling points ; other physical data concerning 

 solutions are not included. Following this is 

 the solubility of the substance in other solvents 

 — first, the inorganic acids ; then alkali and salt 

 solutions, and finally organic substances." 



The theories of solution are not discussed, 

 the term ' soluble ' being used to indicate that 

 " a solution of some sort has been formed." 



The plan of the book is admirable and, so far 

 as our examination has extended, there are no 

 serious omissions. The arrangement of the 

 compounds and the nomenclature adopted are 

 satisfactory and, probably, as good as any that 

 could be employed. 



A synchronistic table of periodicals is added 



in an appendix as well as some formulas and 

 tables for the conversion of various hydrometer 

 scales into specific gravity. 



The work is a worthy successor to the earlier 

 volume of Prof. Storer, and the author de- 

 serves the thanks of his colleagues for the 

 time and labor he has put upon it. 



L. B. Hall. 



SCIENTIFIC JOURNALS. 

 AMERICAN CHEMICAL JOURNAL, JUNE. 



On the Specific Gravities of Mixtures of Nor- 

 mal Liquids : By C. E. Linebarger. The 

 methods used to determine the molecular 

 masses of liquids, which consist either in con- 

 verting the liquid into the state of vapor and 

 determining its specific gravity in this condi- 

 tion, or in determining the change in freezing- 

 or boiling-point of a solvent upon the addition 

 of the liquid, do not throw much light on the 

 molecular complexity of the substance in the 

 liquid state. From work in other lines it is 

 probable that in some cases the molecular ag- 

 gregate is the same in the liquid as in the gase- 

 ous condition ; but in other cases the complex- 

 ity increases as the substance passes from the 

 gaseous to the liquid condition. The present 

 paper is a study of the changes in specific grav- 

 ity which take place when liquids which suffer 

 no change in passage from one state of aggre- 

 gation to another are mixed. In cases where 

 association or dissociation takes place the num- 

 ber of factors which enter into play is so great 

 that no general conclusions can be drawn. In 

 the determinations pycnometers of a special 

 form were used, and in most cases great precau- 

 tions were taken to secure pure substances. If 

 two liquids of different chemical composition 

 are mixed, the volume of the resulting liquid 

 will not be equal to the sum of the volumes be- 

 fore they were mixed, but will be greater or 

 less. This is explained by the fact that dilu- 

 tion diminishes the molecular attraction and 

 the internal pressure. The number of mole- 

 cules in the unit of surface decreases and the 

 volume increases. In this paper the observed 

 and calculated results for a large number of 

 mixtures are given ; but the data at command 

 at present is not sufficient to enable one to 

 draw any general conclusions. 



