6o8 MOTONORI MATSUYAMA 



therefore two quite distinct problems. The investigations of Professor Mat- 

 suyama relate to the second of these. 



The method of Matsuyama is, so far as I know, unique in that he deals 

 with bundles of crystals which have a common known orientation. He thus 

 brings movement along the gliding planes into experimental competition with 

 movement between the crystals. All are familiar with experiments upon the 

 yield of glacier ice where the mass under test was formed of many crystals of 

 diverse orientation, but this very diversity of orientation stood in the way of 

 a strict interpretation of the results. Matsuyama, however, so selected his 

 prisms and cylinders as to force an alternative between combined movement 

 on gliding planes and movement between the crystals. His method and his 

 achievement are therefore notable. 



It is further to be observed that in his experimentation he used the tor- 

 sional method, following Michelson, in which, the errors arising from the 

 stretching or compression of the prisms or cylinders are avoided, since the 

 cross-section remained constant throughout the trial. But as check upon 

 the results of torsion, Matsuyama added the method of bending in which 

 stretching on one face and compression on the other were involved. In the 

 interpretation of the results of this method he called in the resources of the 

 petrographic microscope with the discriminating results given in the text. 



INTRODUCTION 



The motion of an ice sheet along the mountain slopes and over 

 a large area of the Continent may be caused by more or less differ- 

 ent forces. Besides the external forces, it is also important to 

 know what is the behavior of the ice itself in such motion. Numer- 

 ous works have been published on these problems, among which 

 those of McConnell and Miigge are famous and have been referred 

 to by many authors. According to them an ice crystal can be 

 sheared more easily in the direction parallel to the basal plane than 

 in any other direction. The elaborate works of the members of 

 the Cornell University geological staff' added important contri- 

 butions to the same line. Their idea is that the gliding planes of 

 ice crystals arranged parallel to their basal sections control the 

 behavior of an ice mass as the main factor. 



Deeley^ calculated the viscosity of ice from Main's experiment 

 and found its value to be 6Xio'^ c.g.s. at o° C, while his own 

 observations on Swiss glaciers gave 125X10'^ c.g.s. 



' R. S. Tarr and J. L. Rich, Zeits. f. Gleis., Vol. VI (191 2), pp. 225-49; R. S. Tarr 

 and O. D, von Engeln, Zeits. f. Glets., Vol. IX (1915), pp. 81-139; O. D. von Engeln, 

 Amer. Jour. Sci., Ser. 4, Vol. XL (1915), pp. 449-73. 



^ R. M. Deeley, Geol. Mag., New Ser. 5, Vol. IX (191 2), pp. 265-69. 



