TRANSACTIONS OF THE SECTIONS, 5 
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- more than five, sometimes less than two, but with no progressive dif- 
_ ference. He had next followed another diurnal wave up the Channel, 
and had found the same general approximation from the Land’s End 
and Brest to the Isle of Wight; but in the Southampton waters, and 
so on to Portsmouth, the diurnal wave was thrown out of its course so 
_ much as to affect the tides in a reverse order to that which took place 
_ in the previous part of its course ; so that if two successive tides, A, B, 
_ progressed from Bridport to Southampton, a was higher than 8 at the 
_ first place, and 8 higher than a at the second. He referred also to the 
double tides (four in twenty-four hours) which occur in the Solent Sea, 
and invited the attention of persons residing in the neighbourhood of 
_ those coasts to the investigation of this subject, since such persons can 
best determine over what extent of coast this double tide prevails— 
how, at the extremities of its range, the double tide grows out of the 
 single—at what intervals the two tides occur—which is the greater, 
and how these relatious vary at different places,—and whether these 
_ changes can be connected in a definite manner with the tidal currents. 
He added that, in some places, instead of four or two tides in the 
_ twenty-four hours, there appears to be only one, especially on the 
- coasts of Australia. He observed, that he conceived he had already 
evidence to show that these supposed single day tides were, in fact, 
_ only extreme cases of great diurnal inequality ; and he stated that the 
_ Admiralty, in pursuance of suggestions made by him, through Captain 
Beaufort, the hydrographer, had directed observations to be made at se- 
_ veral points on the coasts of Australia, which he hoped would enable him 
to decide this question, and to draw from them the laws of such cases. 
On the Tides of Dundee and Glasgow. By Davip Mackie, Lec- 
turer on Natural Philosophy, Glasgow Mechanics’ Institute. 
_ The author of this paper having been solicited about three years . 
ago to furnish tide-tables for Dundee and Glasgow, was led to compare . 
the results of his calculations with the actual times of high water at 
these ports. From the great discrepancies frequently observable, the 
data made use of necessarily became extremely dubious. With the - 
view of obtaining correct data, and of co-operating, as far as in his 
_ power, with the eminent individuals who have recently given a new 
_ impulse to such inquiries, he was fortunate in inducing Lieutenant 
Smart, harbour-master, Dundee, to undertake a series of observations 
on the tides at that port, while at Glasgow he undertook a similar 
_ series of observations himself. The observations of Lieutenant Smart 
_ were continued from January Ist till September 3rd, 1837. They in- 
_ clude the time and height of the tide morning and evening, the state 
of the barometer and thermometer, and the character and direction 
_ of the wind. At Dundee, the interval of time at which the tide 
follows the meridian passage of the moon, on the days of full and 
_ change, is subject to considerable variation, sometimes being only 
2 hours, and at other times 3 hours; but by taking the average 
of all the intervals which occurred between the time of high water 
and the moon’s northing or southing, from new till full, during the 
