for the Advancement of Science. 391 
the ship’s speed being increased from nine to eleven. _knots, and the ob- 
liquity of the ship’s course to the direction vo y the waves was 
three points. On the 9th, two days after the abo¥e* condition of the - 
the same ridge. ‘The crests often curled over, but.none ag 
the height of a thirty feet wave, and broke fora wide space, estimated 
at fifty to one hundred yards in continuity. aS 
Miscellaneous Notes and Sug gestions. — “The ‘Bide adopted i in. 1 these’ 
: researches of finding the height ‘of waves is, I believe, quite satisfa r¥y 
"and, observed with care and with relation to: numbers or proportion OF 53 
depression of 3’ 49”, the distance of the visible horizon, as seen “es aS 
this en, would 'be 4-45 statute miles, and the actual depreacail 
feet due to the distance of the summit’f the wave when the ship Was # 
in the nsidet of the hollow, could one be id is foot or 2°16 ine = 
Other modes of determining the width of a wave—or the extent betwixt, : 
summit and summit—much | veata rable to that descsibed ihe only availa aa 
_ able one I could devise) might easily be adopted - eel the manage- 
; of the ‘ship was in the hands of the obser ver. In steam ships the 
the ship w whet going in the direction of the wave or against the wave ; 
the ratios of the time of transit of wave-crests, Giles different rates of « 
sailing of the ship might yen results very close to the buy n mod- 
~ 
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- 
= 
= 
a 
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9°) 
ay 
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oO 
- 
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2 =. 
2. 
= 
u 
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ai 
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bes: fal 
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‘i ail. e, 
or The uthor referred, in conclusion, to the forms of wave crests, and 
heights, modified by crossings, interferences, and reflections. 
On Metallic Reflection ; by Prof. G. G. Stoxes. 
The effect which is produced on plane-polarized light by reflex- 
ion at the surface ofa metal shows that if the incident light be supposed 
Fah glass plate. Mr. Airy’s paper is published im the Cambridge 
Philosophical Transactions. M. Jamin has since been led to the same 
a: in observing the phenomenon. The object of the present 
tion was to point out an extremely easy mode of deciding 
