THE SENSE OF FEELING. 265 



in general ] To the knowledge of the form and size conduces, partly what we 

 have termed the sense of place in the skin, which, in a manner to be hereafter 

 explained, announces the extent and situation of the points of the skin which 

 are touched, partly the muscular feeling, which, as already shown, represents 

 to us at every moment the relative position of our members, and informs us in 

 the present case that the parts of the hand touched by the object enclose an 

 orbicular space. "Were the ball too large to be encircled by the hand the touch- 

 ing of a section of it would for the most part sufEce to convey the idea of rotuu; 

 dity, the known form of part of the surface affording an inference as to the 

 rest, but a certain determination is arrived at if a linger b# exploringly moved, 

 here and there, over the surface of the whole object, and the muscular feeling 

 which one has learned from experience to regard as the inseparable concomitant 

 of movement in a circle accompanies all these movements. The similarity of 

 this feeling, in whatever direction the finger be moved over the object, apprises 

 you that the form corresponds to the conception which you have learned to 

 form of a ball. Whether the ball be rough or smooth is determined by the 

 sense of place in the skin; we call it smooth, when the intensity of the sensation 

 is precisely the same at all the points of the skin, which through the sense just 

 mentioned, we know to be situated near one another ; we call it rough when 

 several parts of the skin at certain small distances from one another are felt 

 to be more strongly pressed than the intermediate parts, whence we refer the 

 occasional stronger impressions to corresponding prominences in the surface 

 touched. We yet more sensibly distinguisli the roughness and smoothness 

 when we move the finger-end over the surface, to try. whether the successive 

 impressions made on the same points of the skin are equally strong, or altern- 

 ately stronger and weaker from gliding over the prominences and depressions. 

 The weight of the ball is conceived of either directly from the intensity 

 of the sensation of pressure in those parts of the skin on which it rests, or 

 from the intensity of the muscular feeling — that is, from the sensible de- 

 gree of effort which must be put forth to sustain or raise it. We compare 

 the weight with the acquired idea of the size of the ball, and thence form a 

 judgment of its relative heaviness or the specific gravity of the material of 

 which it is composed. We decide that the ball is hard or soft, elastic or firm, 

 from the amount of resistance which it opposes to compression, and of the 

 amount of this resistance we judge from the degree of conscious exertion of the 

 muscles, and from the increase of strength in the sensation of pressure with 

 the increasing effort employed to produce compression. If, finally, we ascertain 

 that relatively to its circumference the weight of the ball is considerable, that 

 a sensation of cold is communicated, (what that is we shall presently see,) we 

 conclude that the object is of metal, since we know from experience that it is 

 to metal these properties pertain. This example will serve to show by what 

 complex and circuitous processes the comprehensive judgment, which almost 

 at the moment of the touching stands ready formed before the mind, is elabo- 

 rated; will serve to show the mechanism of the manifold operations of the soul, 

 through whose co-operative working, schooled by experience, the raw material 

 of the mere sensations is, with wonderful rapidity, transformed into an harmo- 

 nious and colored image which we are accustomed thoughtlessly to receive as 

 the substance, simply and directly, of the sensation ; will serve, in fine, to show 

 what part in this is borne by the sensation of pressure with its single charac- 

 teristic. 



Every one knows that the strength of tlie sensation of pressure corresponds 

 to the force of the pressure on the skin, the one increasing or decreasing with 

 the other. Without this proportionality, one of the most valuable functions of 

 our sense of touch, the comparative estimate, namely, of the force Avitli which 

 different objects exert a pressure, and cousequentlv the discrimination of weight 



