252 SYDNEY T. KLEIN^ F.L.S. P.R.A.S., ON THE GREAT REALITY. 



Dr. Walker can study the rate of beats in any insect's wing by 

 noting the pitch of the sound given out by that wing ; this will give 

 the exact number of beats per second ; the highest rate which has 

 been recorded, as far as I know, is about 12,000 per second, the 

 pitch in this case being 5J octaves above the ordinary pitch of a 

 man's voice, or 4J above a woman's. I made a curious discovery 

 last summer whilst trying experiments for perfecting my Time- 

 Microscope. I found, as explained in my paper, that as the rate of 

 perception was increased until it approached the rate at which time 

 may be said to flow, motion gradually slows down, until at a certain 

 point it ceases to give evidence of movement. I took the common 

 house fly, and ascertained that its wings beat about 900 times per 

 second, and by experiment I was able to prove that it had clear 

 sight perception of frequencies up to, at all events, 600 per second, 

 by the following means : — I found that if I approached the fly at 

 the rate of 3 inches per second it always flew away, but at 2 inches 

 per second it had no perception of movement, and I could, four 

 times out of five, put my finger upon its back and hold it fast. It 

 was curious to see it turn its head to look at my approaching finger, 

 but it evidently could not see that it was moving. I tried this 

 experiment on other kinds of flies, and in the case of a large 

 dragon-fly, settled in the middle of a road, which I had several 

 times tried to get near by walking slowly, I found that I could only 

 approach it at the rate of about half an inch per second, thus giving 

 a rate of perception to that insect of only about 200 per second, 

 and I was able to pin it down to the ground with my finger after 

 taking several minutes to approach it. This, and other experiments 

 I have made, provided a curious proof of the conclusion I had arrived 

 at by other means, that time and space, and therefore motion, cease 

 to exist as objective realities when the rate of perception is 

 sufficiently increased. 



In conclusion I would like to say that I fully appreciated from 

 the commencement that the subject of my discourse is far too vast 

 to be adequately covered in the short space allotted to papers read 

 before this Society. I have only been able to touch, and that 

 briefly, on one of the many aspects of the Great Reality, but if I 

 have succeeded in interesting the members and have given reason 

 for thought for other minds to work upon, my object in addressing 

 you to-night has been fully attained. 



