5 
relative to physical Optics . 
Table I. Obs. 9. N. 
Distance of the knives from the aperture - - ioi. 
Distances of the paper 
from the knives - if, 3}, 8f, 32, 96, 13 1. 
Distances between the 
edges of the knives, op- 
posite to the point of 
concourse - .012, .020, -034, .057, .081, .087. 
Interval of disappearance .0000122, .0000155, -0000182, .0000167, .0000166, .0000166. 
Table II. Obs. 3. N. 
Breadth of the hair ... 
Distance of the hair from the aperture 
Distances of the scale from the aperture 
(Breadths of the shadow - - 
Breadth between the second pair of bright lines 
Interval of disappearance, or half the difference of the paths 
Breadth between the third pair of bright lines 
Interval of disappearance, f of .the difference 
Table III. Exper. 3. 
Breadth of the object - 
Distance of the object from the aperture 
Distance of the wall from the aperture 
Distance of the second pair- of dark lines from each other 
Interval of disappearance, J- of the difference 
■ 
ago* 
- 
144. 
150, 
252. 
3") 
* 
4 
TT* 
.OOOOI5I, 
.0000173, 
4 
3 
TT’ 
1 o’ 
.OOOOI3O, 
;ooooi43. 
434 * 
125. 
- 250. 
1.167. 
.0000149. 
Exper. 4. 
Breadth of the wire - 
Distance of the wire from the aperture 
Distance of the wall from the aperture 
(Breadth of the shadow, by three measurements 
Distance of the first pair of dark lines 
Interval of disappearance 
Distance of the second pair of dark lines 
Interval of disappearance 
Distance of the third pair of dark lines 
IntervaLof disappearance 
- .083. 
32. 
- 250. 
.815, .826, or .827; mean, .823.) 
1.165, 1.170, or 1. 160; mean, 1.165. 
- .0000194. 
1.402, 1.395, or 1.400; mean, 1.399. 
.0000137. 
1.594, 1.580, or 1.585; mean, 1.586. 
» - - .0000128, 
