The human sensorium : investigated as to figure by a course of pressures on the eyes, and by the induced phases and bearings of those sensations of colors called peacock's feathers : being a second supplement to the Rationale of cerebral vision / by John Fearn.

  • Fearn, John, 1768-1837.
Date:
[1832]
Catalogue details

Licence: Public Domain Mark

Credit: The human sensorium : investigated as to figure by a course of pressures on the eyes, and by the induced phases and bearings of those sensations of colors called peacock's feathers : being a second supplement to the Rationale of cerebral vision / by John Fearn. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    circles, as well as on a variety of other points, will make our secondary course. It only remains to explain, that the word—Sensorimn or Sensonj—is employed here instead of the term Sentient Subject or Sentient, when no mistake can arise from this use of terms. The Sentient Subject, moreover, is the Percipient Subject: But, as it forms a most important con- sideration in the present inquiry, in confirmation of the re- sults of my former speculations on this subject, that the Mind estimates objects from a Common centre of Percipience within itself; from which common pointy all Companies or Pluralities of Local Relations or Bear- ings of Sensations of Colors are perceived or adjudged: this consideration renders it requisite that a percipience of a SINGLE mass, or point, of Sensation of Color, and a percipience of the several local bearings of ANY plu- rality of sensations of colors, demand a due distinetian in the phraseology employed in treating of them. As there is no fact within the mind that is more certain; and, no fact in external nature that is so certain ; as the ex- istence of this Common Centre af Percipience; it must be rigorously held in view, in all our researches on the Sub- ject. I have already pointed out, (in Prop. 2,) that, among; other facts, this Principle is the sole foundation and support of Optical Science and Astronomy. These considerations being placed in the reader's view, I proceed to the proposed induction. Experiments and Phenomena^ I.—If we institute a pressure, with a pin's head, verti- cally all round the exterior of the globe of the eye, as far back as the parts will conveniently admit; this process will impress a Transverse Vertical Circle, about half way between the pupil and the Posterior Pole of the eye, or, in other words, it will delineate that great circle of the eye which I have called its Equator.