GEOPHYSICAL LABORATORY. 145 



clan belong the dilute-solution approximations. In dealing with dilute solu- 

 tions it is usual to assume some relation between composition and thermo- 

 dynamic properties which will enable a divariant equilibrium such as that 

 between ice and a dilute salt solution, to be treated as a univariant equili- 

 brium. It was shown by Gibbs that when the amount of one component 

 approaches zero, such a relation becomes possible, and he indicated the form 

 the relation would take. Making certain explicit assumptions, he further 

 identified the constant value which the rate of change of the potential of 

 water with addition of salt approaches as the amount of salt approaches zero, 

 with the gas constant for one gram of the solute. Making these assumptions, 

 the derivation of the ordinary dilute solution laws is easy, and this method 

 of derivation has the advantage of confronting us squarely with the assump- 

 tions involved in these dilute-solution approximations. 



(456) Realization of absolute scale of temperature. Arthur L. Day and Robert B. Sosman. 



Dictionary of Applied Physics (R. T. Glazebrook, Editor), vol. 1, pp. 836-S71. 

 1922. 



This paper is a comprehensive outline and review of the thermodynamic 

 scale of temperature and its realization by experimental means. The sub- 

 ject is treated under the following heads: Temperature scales; forms of gas- 

 thermometers; basic experimental results with gas-thermometers; means of 

 comparison of gas-thermometers with secondary standards; comparison of 

 gas thermometers with secondary standards in the range of 0°to 100°; —273° 

 to 0°; 100° to 500°; 500° to 1600°; the sources of error in gas thermometry. 



(457) Glass technology. George W. Morey. J. Ind. Eng. Chem., 14, 823-824. 1922. 



A review of the progress of glass technology during the preceding two years. 



(458) The use of minerals as radio-detectors. H. S. Roberts and L. H. Adams. Am. 



Mineralogist, 7, 131-136. 1922. 



This paper, which was written at the request of the editor of the American 

 Mineralogist, contains a brief exposition of the operation of the crystal 

 detector, a list of the substances most commonly used, together with a tenta- 

 tive explanation of their action. It is followed by a list of the more important 

 references to periodical literature on the subject. 



(459) The behavior of inclusions in igneous magmas. N. L. Bowen. J. Geol., 30, 513-570. 



1922. 



The observed effects of magmas upon inclusions are usually to be referred 

 to an action other than the direct solution of inclusions in superheated magma. 

 An application of the conception of the reaction series to the solution of the 

 problem affords an explanation of the effects of magmas, even though satur- 

 ated. Certain principles governing the effects of liquid upon inclusions 

 belonging to reaction series can be developed by studying the equilibrium 

 diagrams of systems involving both continuous and discontinuous reaction 

 series. In this manner it can be decided definitely that a liquid saturated 

 with a certain member of a reaction series is effectively supersaturated with 

 all preceding members of that series. It can not dissolve such members, 

 but can only react with them to convert them into the members with which 

 it is saturated. The reaction is not a simple subtraction from the liquid of 

 the material necessary for this transformation, but some precipitation from 

 the liquid itself is involved and the liquid ordinarily maintains its position 

 on the same saturation surface. The products of crystallization from the 

 liquid and the possible course of fractional crystallization are thus unaffected. 



On the other hand, a liquid saturated with a certain member of a reaction 

 series is unsaturated with all subsequent members of the series. Inclusions 

 consisting of these later members can become a part of the liquid by a sort 



