634 proceedings: philosophical society 



Mr. Swann referred to conflicting theories between the chemist and 

 the physicist with reference to the structure of the atom. He thought 

 that perhaps some part of the apparent excellent agreement of con- 

 stants might be due to a juggling of the 27r-factor in the computations. 

 Mr. Dellinger thought that Mr. Swann's last remark explained some 

 agreements found in recent contributions. 



Mr. W. J. Humphreys presented a paper on The magnetic field of 

 an atom. Recent investigations by Weiss, Ritz, Humphreys, Oxley, 

 and Merritt of atomic phenomena and structure were reviewed. These 

 investigations all give varied evidence in favor of the assumption that 

 atoms have powerful magnetic fields which are of the order 10 8 gauss, 

 and which are due, presumably, to orbital revolutions of electrons. It 

 might seem that atoms with such strong magnetic fields would collapse; 

 the author's calculations, however, show that the electric forces between 

 the portions of atomic models of the Saturnian type would be more 

 than sufficient to prevent collapse through the interaction of their 

 powerful magnetic fields. 



Mr. Swann thought the indicated order of magnitude of the atomic 

 fields is large, judging, for example, from computations, assuming a 

 field of 10 8 gauss, of the moment of the equivalent magnet and of the 

 deflection that would be produced in shooting a-particles through a 

 thin piece of magnetic iron. 



The 776th meeting was held on October 14, 1916, at the Cosmos Club. 

 Vice-President Buckingham in the chair; 65 persons present. The 

 minutes of the 775th meeting were read in abstract and approved. 



Mr. A. L. Day presented a communication, illustrated by lantern 

 slides, on Do volcanoes offer evidence in regard to the interior of the earth? 

 Recent studies are helping to emphasize more and more sharply the 

 conclusion that volcanoes are local phenomena of very limited signifi- 

 cance in affording information concerning the interior of the earth. 

 This view is supported by the differences in chemical composition 

 between lava outflows in different parts of the world, by the differences 

 in altitude of the points of outflow even in neighboring volcanoes, by 

 the apparently complete independence of one another of volcano vents 

 which are immediately contiguous, as at Stromboli, Hawaii, and other 

 places, and by the fact that most of the volcanic phenomena appear 

 to derive their energy from gas reactions in which only the gases appear 

 to be of deep-seated origin. The formation of vertical conduits, under 

 this view, is then simply the result of gas reactions ("gas fluxing") 

 which generate sufficient heat to melt the adjacent rock masses and 

 to form more or less vertical outlets for gaseous or liquid products. 

 Neighboring conduits of this kind often show complete independence 

 of action in time, in pressure (as shown by the lava level), and in 

 character of explosive or other activity at the mouth, all of which 

 point to the independence of the local supply chambers to which the 

 vents serve as outlets. Of course, a great rift like the one on the 

 south flank of Mauna Loa, from which two lava streams recently 



