288 NOTES. [BK. II.
can there be in air; and thus that the flesh can be only the medium for tangible impressions—that there must ever be air interposed, that is, between the object and the surface of the body. It may seem now to be supereroga-
tory, but, as the atmosphere had not then been experi-
mentally investigated, crude and contrary opinions, as might be supposed, were entertained concerning it, and its manifold relations. The term "third magnitude" is derived from, or associated with the Pythagorean doc-
trine of number—as of magnitude, continuous length is referrible to one, breadth to two, and depth to three; and, thus, depth is the "third degree" of or relation to magnitude.
Note 3, p. 122. But tangible differ from visible, &c.] "It will be evident that whatever may, in these passages, be erroneous, is traceable to the flesh being regarded as the sense or the medium for the sense of Touch, as, in either case, the Touch, differing from every other sense, would, from what has been maintained, require two media. There seems to be something like forgetfulness in with-
drawing, so to say, the medium in the example given of tangible impression, and supposing that the man and his shield can be simultaneously transfixed.
Note 4, p. 122. The different states of the body as a body, &c.] As the Touch was regarded as a primal or elementary sense, so the qualities, of which it is perceptive, (as hot and cold, dry and moist, &c.) were also regarded
- Metaphysica, IV. 13. I.