Mr. J. Nixon on the Tides in the Bay of Morccambe. 273 



At 5 h 45 ra a.m.; Dip ... 8' 4.3") Low water, 

 6 15 ... 8 41 J morning. 



Mean 8 42 



Refraction T ^.j ... +48 



Half morning variation + 37i 



Corrected dip and height of eye 10 1\ = 91*0 feet. 

 Tabulated do. 10 30 J = 98-0 



Errors —0 23 -7'0 



At 5 h 31 m p.m. Dip 9' 50" 



6 9 50 



Low water, 

 6 20 ... ... 9 52 J evenin S- 



} 



Mean 9 51 



Refraction Jj -flli 



Half evening variation + 5 



Corrected dip and height of eye 10 7f = 91*0 feet. 



Tabulated do. 10 30 ^ = 98*0 



Errors — 23 —7'0 



In the morning there was a strong white frost, which did 

 not recur in the evening. To account for our estimate of the 

 refraction being so much in defect, we must either suppose 

 our tabulated height of the (equinoctial) tide (34 feet) in ex- 

 cess, or that the variation of refraction was less for the light- 

 house than the horizon of the sea, and to precisely the same 

 amount in the morning as evening ! At noon, which was 

 bright and warm, the refraction for the dip and the lighthouse 

 were both less by 4J" than on the preceding day. 



September 16th, 1829. 

 (At 2 h 35 m p.m. Black Comb, 42' 33i" elev. ; refr. (&) 



(6 55 a.m. do. 42 55i T V 



35 p.m. Lighthouse top 5 33± depr. 

 6 45 a.m. do. 5 12 — 



(10 25 a.m. do. 5 17 — ) 



Variation — 21±" 

 At h 23 m p.m. dip 8' 17"; Eye 66*3 feet; refr. +21" 



4i 8 10 — 65'6 25f 



1 o 8 4 — 65'3 31 



1 18 8 4 — 65*2 31 



1 40 8 I — 65'6 34J 



Mean ... 8 7 +28 J- 



Half variation +10f 



rO'39 



Mean refraction ... (s - ?^) = tV +39 



Third Series. Vol. 5. No. 28. Oct. 1 834. 2 N 



