Mat 1, 1908] 



SCIENCE 



697 



direction, that is from the denser towards the 

 lighter mass. 



Mr. Willis thus explains the persistency and 

 periodicity of movement in the lithosphere 

 through the efforts of unstable heterogeneous 

 masses toward equilibrium; efforts which are 

 assisted by variations in molecular arrange- 

 ment, temperature and pressure, and which are 

 directed by the tendency of the heavier masses 

 to spread at the expense of the lighter masses. 

 The resulting tangential strain grows during 

 a prolonged period and produces more or less 

 incomplete efforts towards equilibrium, which 

 are apparent in epeirogenic warping, but from 

 time to time the increase in strain becomes 

 such that the margins of the lighter areas, 

 continents, are crushed in, and an episode of 

 erogenic movement ensues. 



These effects of warping and mountain- 

 building thus result from the mobility of the 

 lithosphere, which is, however, conceived to 

 be highly rigid in relation to sudden stresses 

 or when taken in small masses. 



A sufficient mass to account for all the 

 superficial variations of form that are known 

 is found within a depth of YO to 100 miles 

 below the surface, the geologic results being 

 thus in accord with the determinations by 

 Hayford of the depth of the zones of isostatic 

 compensation. The inner mass of the earth, 

 3,900 miles radius, is conceived to be held in a 

 state of relatively great stability by the high 

 rigidity induced by pressure of the superin- 

 cumbent load, and it is thought to graduate 

 into the relatively unstable superficial layer 

 through decrease of rigidity. The great nu- 

 cleus itself is conceived to be the source of 

 those energies which are expressed in varia- 

 tions of temperature and molecular condition 

 through which the tangential strains gradu- 

 ally develop. 



E. L. Paris, 

 Secretary 



THE AMERICAN CHEMICAL SOCIETY. NEW YORK 

 SECTION 



The seventh regular meeting of the session 

 of 1907-8 was held at the Chemists' Club, 

 108 West 55th Street, on April 10. 



The Wm. H. Nichols medal, awarded an- 

 nually for the best paper read before the sec- 

 tion, was presented to Professor William H. 

 Walker, of the Massachusetts Institute of 

 Technology, for his paper on " The Corrosion 

 of Iron and Steel." 



The ceremony of awarding the medal was 

 witnessed by many prominent members of the 

 society. The chairman of the section. Pro- 

 fessor Sherman, after reading a letter from 

 the donor of the medal. Dr. Nichols, who 

 expressed his regret at not being present, spoke 

 of the great diversity in the subjects of re- 

 search for which the authors had received the 

 medal. These included agricultural chem- 

 istry, investigation of rare elements, organic 

 synthesis, technical chemistry and finally a 

 physico-chemical investigation of the proper- 

 ties of one of the most important metals. 



The president of the society. Professor 

 Bogert, in presenting the medal, gave a short 

 history of the professional career of the re- 

 cipient. He said, in part, that W. H. Walker 

 graduated from Pennsylvania State College 

 in 1890 and took his doctor's degree at Got- 

 tingen about a year later. Since then he has 

 been professor of industrial chemistry at the 

 Massachusetts Institute of Technology and 

 lecturer on that subject at Harvard. Outside 

 of his teaching he has been very successful in 

 technical work, having made improvements in 

 the manufacture of cut glass, in annealing 

 silver, in brewing processes and in the prepa- 

 ration of wood products. He has also con- 

 tributed much to the chemistry of cellulose. 



Professor Walker, in acknowledging the 

 medal, gave a resume of the paper for which 

 he received the award and outlined further 

 investigations on the same subject which are 

 now in progress. 



The remainder of the evening was devoted 

 to papers by Chas. Baskerville on " Courses 

 in Chemistry for Colleges," and Jerome 

 Alexander on " The Effect of Colloids on 

 Crystallization : the Function of Gelatin in Ice 

 Cream " — preliminary paper. 



C. M. Joyce, 

 Secretary 



