August 20, 19091 



SCIENCE 



255 



without significance. The microscopical examina- 

 tion of the fiber promises little because of the 

 variation in the fiber in fish of difi'erent sizes, and 

 also in difi'erent parts of the fish. 

 Determination of Caffein in Coffee: A Comparison 

 of the Bilger and Fricke Method with a Modifi- 

 cation of the Gomberg Method: A. L. Sullivan. 

 Five grams of coiTee were boiled with four 

 separate portions of water; the combined filtrate 

 treated with 5 c.c. of saturated lead acetate, fil- 

 tered and washed and the filtrate freed from lead 

 by means of hydrogen sulfide. The solution was 

 evaporated to about 25 c.c, cooled and extracted 

 in a separatory funnel successively with 50, 25, 

 25, 25 c.c. of chloroform. The combined chloro- 

 form extract was freed from chloroform and dis- 

 solved in about 25 c.c. of water * c.c. ( 1-5 H,SO, ) 

 and 20 to 25 c.c. approximately N/10 iodine solu- 

 tion added. The precipitate formed immediately 

 and was allowed to stand for two hours. The 

 solution was then filtered and washed with a 

 dilute acidified solution of iodine (1 part N/10 

 iodine to 4 of water). The precipitate after 

 standing for a few minutes was dissolved in 

 sulphurous acid and water. The solution was 

 heated until the iodine was driven off, allowed to 

 cool and made slightly alkaline with ammonia. 

 The volume should be about 25 c.c. The solution 

 was again extracted with chloroform, using the 

 same amount as before. The chloroform extract 

 was then evaporated in a tared dish, dried in a 

 water oven and weighed. 



It was found that the extraction of caffein from 

 its aqueous solution by chloroform was prac- 

 tically complete. 



The results seem satisfactory and it is apparent 

 that the method described is suitable for deter- 

 mination of caffein in coffee. The results are 

 slightly higher than those obtained by the A. 0. 

 A. C. method. 



The Relation of the Iron Content to the Color of 

 Soils: F. K. CAMEEOif and W. O. Robinson. 

 A chemical examination of twenty typical red 

 and yellow soils shows that iron oxides are the 

 inorganic coloring matter of these soils. Man- 

 ganese is present in amounts too small to con- 

 tribute to the color. 



The causes in color variations of iron-colored 

 soils is sometimes ascribed to the presence of dif- 

 ferent hydrates of iron oxide. From the compara- 

 tively small variation in soil temperature in near 

 localities where the two tints are present it is 

 reasoned that this view is incorrect, and that the 

 iron is in much the same state of hydration. 



The color is sliown to be due to a film of oxides 

 of iron and aluminum, organic matter, silica, etc., 

 surrounding the soil grains. Bj' comparing the 

 color of soils with the iron content and mechanical 

 analysis, it is proved that the thickness of the 

 film causes the variations in color, the thin film 

 of the colored oxide causing the soil to appear 

 yellow, while a thicker film gives a red shade to 

 the soil. This view was confirmed by precipitating 

 ferric hydroxide upon sands of different-sized 

 grains and upon quartz flour, using such amounts 

 as to keep the percentage of iron constant and 

 vary the thickness of the film. 



The following papers were reported by title: 

 A Chemical Study of the Interaction of Ferment- 

 ing Manures and Ground Rock Phospliate: E. 

 V. McCoLLUM and W. E. Tottingham. 

 The Estimation of Organic Matter in Soils: G. H. 



Failyek and W. H. Waggaman. 

 The Relation of Moisture Content to the Beat 



Conductance of Soils: H. E. Patten. 

 The Element System of Nomenclature in Soil 



Chemistry: C. G. Hopkins. 

 The Interpretation of Soil Analyses with Respect 



to Phosphoric Add: G. S. Fbaps. 

 The Potash of the Soil: G. S. Fraps. 

 The Oxidation of Organic Matter in the Soil: 



G. S. Fbaps and N. C. Hamneb. 

 The Constants of Pecan Oil: G. S. Fbaps. 

 The Hydrolysis of Salicyn by the Enzyme Emul- 

 sion: C. S. Hudson. 



No abstracts have been received for papers read 

 before the sections of Fertilizer Chemistry, and 

 the Industrial Chemists and Chemical Engineers. 

 The titles follow: 



FERTILIZER CHEMISTRY SECTION 



F. B. Carpenter, chairman 



J. E. Breckenridge, secretary 



Potash Tests in Commercial Fertilizer: J. E. 



Breckenridge. 

 The Measurement of Crude Sulphuric Acid: F. B. 



Porter. 

 The Corrosive Action of Alkaline Tank Water 



upon an Evaporation and a Remedy: R. H. 



Fash. 

 The Use of Wood Ashes in Commercial Fertil- 

 izers: R. H. Fash. 

 Preparation and Neutralization of the Ammonium 



Citrate Solution: J. M. McCandless. 

 The Needs of Texas Soils for Fertilizers: G. S. 



Fraps. 

 The Scientific Preparation of Phosphate Samples 



for Chemical Analysis: P. D. Youngblood. 



