688 Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. A New Method for the Quantitative Estimation of Vapors 

 in Gases. — A process has been described for this purpose by 

 Harold S. Davis and Mary Davidson Davis of the University of 

 Manitoba. It is particularly interesting in its application of 

 well-known principles in a new way. The apparatus consists of 

 two flasks connected by a mercury manometer and provided with 

 suitable outlets which can be closed, and a device for crushing 

 small bulbs of liquid within the flasks without changing their 

 gaseous contents. When the flasks contain air or other gas under 

 the same pressure, as shown by the manometer, for instance at 

 atmospheric pressure, and then bulbs containing an excess of a 

 volatile liquid are broken in each flask, this vapor, if it is the 

 same in each case, will exert the same pressure by evaporation, 

 and the manometer will remain unchanged. However, if a gas 

 or air in one of the flasks is already partly (or wholly) saturated 

 with the vapor of a liquid while the other flask is free from this 

 vapor, then upon performing the same operation of saturation 

 in both flasks, the manometer will show a difference of pressure 

 due to the original partial saturation, and this serves as a means 

 for determining the amount of vapor that was present. In this 

 way the authors have succeeded in determining satisfactorily the 

 amounts of benzene vapor in samples of air. For details of the 

 apparatus and for other applications of the method the original 

 articles must be referred to. — Jour. Indust. and Eng. Chem., 10, 

 709, 712, 718. h. l. w. 



2. The Determination of Organic Matter in Soils. — The deter- 

 mination of organic matter in soils by loss of weight upon the 

 ignition of the substance gives highly erroneous results on account 

 of the presence of hydrated minerals, carbonates, and unoxidized 

 inorganic substances, while the determination of total and inor- 

 ganic carbon in such materials gives uncertain results on account 

 of the necessarily arbitrary factor that must be used in calculat- 

 ing the organic matter from the amount of organic carbon 

 present. J. B. Rather has now devised a method for this deter- 

 mination which is based upon the treatment of the sample of 

 soil successively with water and then repeatedly with a mixture 

 of dilute hydrochloric and hydrofluoric acids. The residue is 

 collected upon an asbestos filter, the solutions are evaporated 

 to dryness, and a final ignition of the dried residues gives the 

 amount of organic matter by loss. The details of the process 

 will not be given here but it may be stated that the method 

 appears to be the most satisfactory one yet devised for the pur- 

 pose. — Jour. Indust. and Eng. Chem., 10, 439. h. l. w. 



