...chief economic importance. Doctor Merrill" explains the cause of these contrasts very satisfactorily : The impact of the hammer breaks up the granules on...the eye is that of whiteness. The darker color of a ]K)lished surface is due merely to the fact that, through careful grinding, all these irregularities...

...planes in the feldspars. It is for this same reason that the hammered surface of a rock of this type is of a lighter color than the natural rock face or...hammer breaks up the granules on the immediate surface, not, it may be to the point of immediate disintegration, but enough so that the light falling upon...

...cause of these contrasts very satisfactorily : The impact of the hammer breaks up the granules 011 the immediate surface, so that the light falling upon...the eye is that of whiteness. The darker color of a l>olished surface is due merely to the fact that, through careful grinding, all these irregularities...

...cause of these contrasts very satisfactorily : The impact of the hammer breaks up the granules on (ho immediate surface, so that the light falling upon...the eye is that of whiteness. The darker color of a IMilished surface is due merely to the fact that, through careful grinding, all these irregularities...

...planes in the feldspars. It is for this same reason that the hammered surface of a rock of this type is of a lighter color than the natural rock face or...hammer breaks up the granules on the immediate surface, not, it may be to the point of immediate disintegration, but enough so that the light falling upon...

...chief economic importance. Doctor Merrill " explains the cause of these contrasts very satisfactorily : The impact of the hammer breaks' up the granules on the immediate surface, so thiit the light falling upon it is reflected, instead of absorbed, and the resultant effect upon the...