MR. LUBBOCK ON THE TIDES. 
265 
Table XXIX., showing the Calendar-month Inequality, as deducedfrom Bernoulli’s 
theory and from observation. In making this comparison the inequality is supposed 
to arise from the corrections d and d h due to the declinations of the sun and moon 
and to the sun’s parallax, the moon’s parallax being 5 7 1 throughout. See Plate XIX. 
Table XXX., showing the Moon’s Parallax Correction, as deduced from Ber- 
noulli’s theory and from observation. In this comparison the declinations of the 
sun and moon are supposed equal to 15° throughout. The actual declinations are 
given in Table VI. for each category, in order to show that this supposition is ad- 
missible. See Plate XX. 
Table XXXI., showing the Moon’s Declination Correction in the Interval and 
Height, as deduced from Bernoulli’s theory and from observation. See Plate XXI. 
The quantities in this Table are influenced by the sun’s declination, which is given for 
each category in Table X. 
The parallax and declination corrections have been calculated by Mr. Jones from 
the expressions 
tan 2 4 = V + h = D + E {A cos (2 ^ — 2 <p) + cos 2 
Table XXXII., showing a Comparison between the Diurnal Inequality in the In- 
terval, as deduced from theory and observation. 
Table XXXIII., showing that the deviations from the H. P. 57', corresponding to 
the column headed “ Mean” in Table II., have no sensible influence ; so that the 
column in question may be considered as affording the semimenstrual Inequality. 
Table XXXIV., showing that the deviations in the Moon’s Declination from 15°, 
corresponding to the column headed “ Mean” in Table II. have no sensible influence. 
Table XXXV., showing the Correction d ^ for the Sun’s Parallax in the different 
months of the year, according to Bernoulli’s theory. 
Table XXXVI., showing the Correction d h for the Sun’s Parallax in the dif- 
ferent months of the year, according to Bernoulli’s theory. 
Conclusion. 
The expressions which we have employed in calculating from theory the semi- 
menstrual, parallax, and declination corrections, are virtually those of Bernoulli. 
These expressions are in a form well adapted for computation, so that nothing would 
have been gained by employing expressions less exact. 
The approximate expression which Mr. Whewell deduced empirically from my 
former discussion of the London Dock observations for the moon’s parallax correc- 
tion of the interval is 
P' = (P — p) {B + B sin (2 <p — 2 (3) } *. 
* Philosophical Transactions, 1834, p. 37. 
2 M 
MDCCCXXXVI. 
