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(1956). A Simple Matrix Approach to Linear Differential Equations. The American Mathematical Monthly: Vol. 63, No. 7, pp. 472-478.

An interesting application of several important topics from algebra and analytic, geometry offers the students an opportunity to exercise their ingenuity.

In a recent issue of The Mathematics Teacher,1 Harry Sitomer described an experimental program in high school geometry originally recommended to the School Mathematics Study Group by some of its advisers but finally undertaken by the Wesleyan Coordinate Geometry Group.

In developing his numerical and graphical method for solving two-dimensional stress problems, while the authors use a tension member with a semicircular notch as an example, the procedure actually has a wide range of application. Comparison of the calculated results and those obtained from photoelasticity shows close agreement. The maximum value of the stress in the plate used as an example obtained by this method is 3.25. This compares with a maximum of 3.20 obtained photoelastically by Wahl and Beeuwkes and a maximum of 3.05 obtained in the same manner by M. M. Frocht.

Foreword. When a layman asks a mathematician "What is the fourth dimension?" he is usually quite surprised to be told that like the poor, the fourth dimension, and the fifth, and sixth, and nth for that matter, "is with us always". And yet such is indeed the case. For the dimensionality of a collection of objects, i.e. a"space", is nothing but the number of independent data, or coordinates, which must be specified in order to identify uniquely a particular element of the space; and to. insist that spaces of four or more dimensions are completely outside the bounds of experience is to deny that there are collections of familiar elements requiring four or more data for their specification. In Relativity, to mention one example, the elements which are studied are events, and in as much as it takes three space coordinates to tell where, and one time coordinate to tell when a particular event occurred, the "space" of events is four dimensional, although allits elements have as real an existence as any.other objects of scientific inquiry. Similarly, if one considers all the conics which can be drawn in a given plane, real as they are they nonetheless form a five dimensional collection or "space", since five data, for instance the ratios of any five of the coefficients in the general equation