Limit to Defining -iiower. Bij J. J. Li^^ter. 



37 



essentially on the separation from each other of tlie middles of' its 

 squares or stripes (of the same colour), and not on the relative 

 breadth of the black and wliite portions. This separation was 

 therefore carefully taken in the patterns provided, as follows : — 



Stripes- 



Black 0-0272 White 0-0272 broad 



0-0505 

 0-1010 

 0-0818 

 0-0272 



0-0505 

 0-1010 

 0-0272 

 0-0818 



Separation 











, '.. 







n. 



0544 



1010 



2020 



109 



109 



0-0715 



Checquer of black and white squares, the TSeparation \_ 



side of each 0-0505 in \ Vo-0505 x 0-10lJ~ 



Ditto, side of each - 101 in. . . Separation - 143 



101 



Squares, 0*0505 m. white on black ground,) Pi.- t ^u In 



J 4-u • -J J- 4. 4- A ncAK < in stripes of the same > 0* 



and their sides distant 0-0505 . . . . | Vii-po/^th I 



The diameters of the circular apertures through which the 

 patterns were to be viewed were determined with the Microscope, 

 their image being traced by the camera-lucida on paper and then 

 that of a finely divided glass scale on the same. The more minute 

 apertures were pierced by a fine steel point in tinfoil laid on brass, 

 and some attention was given to obtain such as were sufficiently 

 round. 



In the annexed table the third column {d) gives the distances 

 at which the separation (s) of the patterns vanished, seen with my 

 eye through the several apertures {a). 



Dia- 

 meter 

 of 

 Aperture 

 (a) 



Pattern and 

 Separation (8) 



m. 



•094 



■080 

 •062 

 •048 

 •040 

 •034 



Whole I Stripes (ver- 

 pupil tical) 



Stripes . 

 Checquer 



Stripes . 

 Checquer 



Stripes . 

 Checquer 



Stripes . 

 Checquer 



Stripes . 

 Checquer 



Stripes . 

 Ditto 

 Checquer 

 Ditto 



in. 

 •202 



Checquer • 143 



202 

 143 



202 

 143 



Vanish- 

 ing 



Distance 

 (d) 



m. 

 618 



420 



582 

 408 



556 

 390 



Vanishing Distances, as seen by 

 Other Eyes 



J.L. 



J.S.L. 



432 



408 



393 



406 

 342 

 302 



J.C. J.S. 'M.L.iMy. 



618 



Horizontal 



612 



X2 X2 



640 536 408 



X2 X2 



482 408! .. 



102 



348 



365 i329 



274 .. 



297 



279 



273 



273 

 252 

 234 



288^ 

 209 I !! 195 



s 



s 



C5 



o 



3059 



2937 



2881 I 

 2853 / S 



2752 \ g? 

 2727 / g5 



2445 \ ^ 

 2314/ 



1980 

 1944 



1737 

 1692 



O 

 Oi 





iT 



1495 

 1534 



1469] { -^ 

 1454 



•0000323 

 •0000293 

 -0000260 

 ■0000244 

 •0000233 



•0000228 



