May 26, 1905.] 



SCIENCE. 



819 



tution has a decided influence upon the in- 

 ternal friction of the vapor, as will be seen 

 from the following table, representing in each 

 case the average of a number of experiments. 

 The last column gives the comparative vol- 

 umes of the molecules according to the for- 

 mula suggested by L. Meyer, in which ' Y ' 

 is the friction, ' M ' the molecular mass. 



F=. 00003 {^'^^ 



+ 







Substance. 





y. 



I'. 



Methyl ether, (CH,)oO 





1,133.5 



55.53 



Ethyl alcohol, CHeO 





1,100 



58.09 







1,030 



78.2 



Ethyl ether 





944.7 



110.4 



Methyl-propyl ether 





951.8 



100.74 



Methyl-isopropvl ether 





992.3 



96.46 



Etliyl-propyl ether . . • 





874.9 



133.2 







797.6 



170.7 



Di-isopropyl ether 





841.5 



157.8 



The Iodine Absorption of 



Rosin and Shellac: 



A. C. L.\NGMUIR. 



The paper states the results of further in- 

 vestigations in the iodine absorption of rosin 

 and shellac. The various grades of rosin A. 

 to W. W., ranged between 190.1 and 264.5 in 

 the percentage of iodine absorbed. A number 

 of pure shellacs of the years 1890 to 1895 were 

 tested in order to find if there was any varia- 

 tion in different crops. The figures obtained 

 were between 14.3 and 17.4 and are the same 

 as those shown by similar grades to-day. 



Decomposition of Ammonia at High Tempera- 

 tures: William Melville and Alfred H. 

 White. 



The paper embodies the results of a series 

 of experiments carried on in the chemical 

 laboratory at the University of Michigan, by 

 Mr. A. H. White, instructor in chemical tech- 

 nology, and Mr. Wm. Melville. The object of 

 the experiments was to determine if possible 

 the influence of surface contact upon the de- 

 composition of ammonia, also the effect upon 

 the decomposition, of mixing the ammonia 

 with gases, which are generally present in the 

 manufacture of illuminating gas, with a view 

 to increasing the yield of ammonia in the 

 manufacture of coal gas. 



The results have been tabulated, and also 

 plotted in the form of curves, showing the 



effect of increased temperature, rate of flow 

 of gas, and dilution with hydrogen, nitrogen, 

 carbon monoxide and water vapor. 



Mineral AYaters at the St. Louis Exposition : 

 A. A. Breneman. 



The paper gave the experience and observa- 

 tions of the author as chairman of the Inter- 

 national Jury on mineral waters at the St. 

 Louis Exposition. He also drew some com- 

 parisons between the exhibition of 1904 and 

 that at Chicago in 1893, where he filled a 

 similar position. 



Mineral waters at St. Louis were shown 

 mainly in the departments of mines and metal- 

 lurgy, a few only being in the agricultural 

 building. The collection numbered about 160 

 samples. Notable among these was the col- 

 lective exhibit of the U. S. Geological Survey 

 embracing 125 samples of United States waters 

 which are offered for sale, all neatly bottled 

 and arranged on shelves and in a separate en- 

 closure. Most of these were accompanied by 

 analyses and descriptive circulars. Another 

 feature of this exhibit was the illustration of 

 the analysis of each water by a series of small 

 jars containing powders which represented the 

 proportion of the dry ingredients extracted 

 from the waters, a demonstration which gave 

 a much more tangible interpretation to the 

 average visitor than the printed analyses. 



The foreign exhibit was represented by 

 Mexico, Brazil, Argentine and Peru, the last 

 with an alkaline table water of exceptional 

 merit. Mexico sent very good samples with 

 alkaline and sulphureted waters. Germany, 

 Hungary and Portugal monopolized the list 

 from abroad with 8, 19 and 11 samples, respect- 

 ively, while Belgium and Italy with one each 

 completed the European list. These foreign 

 waters deserve particular consideration be- 

 cause of their long transport and time of keep- 

 ing, both tending to accentuate any defects. 

 It would be difficult to find a fault in some of 

 these samples as presented. Germany having 

 the largest trade and greatest experience, 

 rightly leads the list among these. 



As compared with the exhibition of mineral 

 waters at Chicago in 1893, the St. Louis dis- 

 play was smaller and had fewer countries rep- 

 resented, but was, on the whole, of better 



