Page:A manual and atlas of medical ophthalmoscopy.djvu/253



The following types are numbered according to the distance in feet at which they can be read by a normal eye. The acuity of vision is expressed by a fraction of which the denominator is the number of the test-type, the numerator the distance in feet at which it can be read. No. 1. The mouth of this hollow was at the bottom of a great rock, where, by mere accident, I was cutting down -%ome thick branches of trees to make charcoal, and perceived that, behind a very thick branch, there was a kind of hollow place : I was curious to look in it; and getting with difficulty into the mouth of it, I found it was pretty large, that is to say, sufficient for me to stand upright in it, and perhaps another with me : but I must confess to you that I made more haste out than I did in, when, looking farther into the place, and which was perfectly dark, I saw two broad shining eyes of some creature, which twinkled like two stars ; the dim light No. If. from the cave s mouth shining directly in, and making the reflection. However, after some pause, I recovered myself, and began to look round me, when I found the cave was but very small,— that is to say, it might be about t welve feet over, but in no manner of shape, neither round nor square, no hands having ever been employed in making it. I observed also that there was a place at the farther side of it that went in further, but was so low No. 2. that it required me to creep upon my hands and knees to go into it, and whither it went I knew not ; so, having no candle, I gave it over for that time, but resolved to come again. The next day I came provided with six large candles of my own making ; and going into No. 3. this low place I was obliged to creep, as I have said, almost ten yards, which, by the way, I thought was a venture bold enough, considering that I knew not how far it might go, nor what was beyond it. When I had got No. 3i through the strait, I found the roof rose higher up, I believe near twenty feet ; but never was such a glorious sight seen in the island, I dare say, as it was to look round the sides and roof of this cave — the