It is recognized that the proper value of
, for a particular case, can only be determined properly by experiment, but it is interesting to note that, by the theory of earth pressure of an unlimited granular mass, level at the top, the ratio of the lateral to the vertical unit pressure, at any point in the mass, is,
, and that this varies from 0.361 to 0.271, as
, the angle of repose, varies from 28° to 35°, the values of
for wheat, given in some of the experiments. Further, by reference to Jamieson’s experiments on a model bin of smooth steel, 1 ft. in diameter,[Footnote 16] ] filled with sand, for which
