288 



SCIENCE. 



[N. S. Vol. XVI. No. 39&. 



five per cent. The time necessary is fif- 

 teen to twenty minutes. A balance weigli- 

 ing to 0.01 mg. is necessary, if direct weigh- 

 ings are made, but, by a slight modification 

 of the modus operandi, satisfactory results 

 may be obtained with a portable balance 

 weighing to 0.1 mg. 



4}lucose Determination: Edward Gudeman. 

 The determination of glucose or grape 

 : sugars by use of the polariscope , gives in- 

 •correct results, due to the variation of the 

 rotatijig power of these substances being 

 ibetween 80 and 198, instead of the constant 

 175, generally accepted. Method suggested 

 consists in determining the reducing power 

 on Fehling solution directly, after inver- 

 sion at 67° C. and after treatment with 

 malt (as for starch analyses). In- 

 vert sugar is determined by double polari- 

 zation at 20° and 87° C. From these 

 results the amount of reducing and non- 

 reducing substances from the glucose or 

 grape sugar is directly calculated, and the 

 sum of the two taken as the actual amount 

 of commercial glucose or grape sugar pres- 

 ent in the mixtures. 



The Identification, Composition and Analy- 

 sis of Malt Liquors: Charles Lathrop 

 Parsons. 



In three of our northeastern prohibition 

 states the statutes forbid the sale of 'malt 

 liquors.' The task of the chemist is not 

 therefore the usual one of simple alcohol 

 contents, but he is required to prove that 

 the liquor under examination was brewed 

 from malt. The paper gives the analysis of 

 a large number of such liquors and of a 

 few imitations. The identification is mainly 

 accomplished by means of the albuminoids, 

 phosphates, and ash constituents. Analyses 

 show a decidedly poor quality of malt 

 liquor sold in these states and that the per- 

 centages of sulfates in the ash are abnor- 

 mally large, indicating very extensive use 

 of glucose. The chief modifications in the 



methods of analysis from the official 

 methods were the application of Hind's 

 photometric method for sulfates to the ash 

 and the volumetric determination of phos- 

 phates in the ash by uranium acetate, after 

 moistening with concentrated hydrochloric 

 acid and evaporation on the water-bath. 

 (To be published in the Journal of the 

 American Chemical Society.) 



The Distribution of Hydrogen Sulfid to 

 Laboratory Classes: Charles Lathrop 

 Parsons. 



Describes a new generator having the 

 advantages of the perfect automatic action 

 of the Kipp generator, greater regularity 

 of pressure, no second contact with the 

 siilfuric acid, practically complete neu- 

 tralization of the acid, and its immediate 

 removal from the field of action so that no 

 stoppage from the ferrous sulfate occurs. 

 Coupled with this is used a long lead de- 

 livery pipe with exits where desired. These 

 exits are of thermometer tubing specially 

 bent, and of such a length that the student 

 can secure only a limited flow of gas of 

 from one to two bubbles a second. (To be 

 published in the Journal of the American 

 Chemical Society.) 



The Influence of the Groivth of 3Iold upon 

 the Chemical Composition of Oleomar- 

 garine and Butter: C. A. Ckampton, 

 Washington, D. C. 



Analytical results are given of the values 

 obtained from a series of samples of oleo- 

 margarine which had been kept three years 

 and had become infected with a grovrth of 

 mold. These results showed great variation 

 in composition of the fat, chiefly induced 

 by the mold. The practical lesson is con- 

 sidered, in the way of the interpretation of 

 analytical results, and also the theoretical 

 bearing upon the causes and character of 

 rancidity changes in fats. The paper in- 

 cludes a brief resume of the more recent 

 articles on this subject, and the author eon- 



