318 abstracts: physics 



PHYSICS. — The spectroscopic determination of aqueous vapor. F. E. 

 Fowle. Astrophysical Journal, April 1912, p. 149. 

 By laboratory experiments on the transmissibility of radiation through 

 long columns of air containing known amounts of water vapor the 

 dependence of transmission on the water-vapor content has been deter- 

 mined for the intra-red bands <J> and M>. The direct determinations 

 cover quantities of water vapor up to a depth of 0.5 centimeters of pre- 

 cipitable water. Beyond this the determinations have been extended 

 by aid of solar observations made on Mount Wilson. This extension 

 does not require assumptions as to the actual quantities of water vapor 

 in the solar beam, but only as to the relative quantities as fixed by the 

 length of path of the beam. As the purity of the spectrum enters into 

 the results it has been necessary to determine the dependence of trans- 

 mission on water vapor for different values of combined slit- and bolom- 

 eter-width. While the experiments have been made only at atmos- 

 pheric pressure, a computation is given which shows that the results 

 are probably applicable with slight correction to the actual pressures 

 at which water vapor occurs in the atmosphere. Accordingly, a method 

 has been established by means of which the total quantity of water 

 vapor between the observer and the sun may be easily determined by 

 spectro-bolometric observations. It is proposed in subsequent papers 

 to give applications of the method. F.. E. F. 



AGRICULTURAL PHYSICS.— The effect of soluble salts on the physical 

 properties of soils. R. 0. E. Davis. Bulletin 82, Bureau of Soils. 

 The addition of small amounts of soluble salts affect the physical 

 properties and therefore the structure of the soil. No predictions can 

 be made regarding the specific direction or the amount of the action of 

 salts on particular soils. The effect of salts is more pronounced in a soil 

 containing a large percentage of fine soil particles and this leads to the 

 conclusion that colloid-like clay particles are affected most by soluble 

 salts and in turn effect most the structure of the soil. The actual nature 

 of the condition produced in the smallest soil particles is not known 

 beyond the fact that flocculation and deflocculation may be produced. 



M. X. Sullivan. 



AGRICULTURAL CHEMISTRY.— The distribution of organic con- 

 stituents in soils. Oswald Schreiner and E. C. Lathrop. Jour- 

 nal Franklin Institute, August. 1911. 

 Twenty-six samples of soils from eleven different states were examined 



for known organic soil constituents which had previously been isolated 



