of Edinburgh , Session 1885-86. 
797 
flow outwards again until ebb tide is completed, and tbe force of 
the flood tide is strong enough to ensure reversal of direction all 
along tbe estuary. 
Tbe subject of leaky tides deserves more careful observation for a 
longer period than we were able to devote to it. 
Explanation of Plate XXVIII. — By way of a summary of the 
principal results, the meaning of the various curves in the Plate may 
be briefly pointed out. 
Pigs. 1 and 2 show the variation of temperature and density dur- 
ing an entire tide at Kincardine on 27th April 1886. 
Pig. 1. Kincardine, 27th April 1886, from 10.30 o’clock to 16.30 
o’clock, i.e., from 2 hours ebb to 2 hours flood. Depth 
varied from 4 fathoms 4 feet to 3 fathoms 2 feet. 
Curves showing the variation with time or phase of tide of 
the temperature of the water: — 
(a) at the surface, 
( b ) at 3 feet below surface, 
(c) at 2J fathoms above bottom, 
(d) at bottom. 
Abscissae mark time, ordinates temperature. 
Surface curve is made irregular by sun-heating. The others 
show that while the bottom layer attains its maximum tem- 
perature an hour before low water, the intermediate maxi- 
mum is later, and the water near the surface is warmest after 
low water. The shearing motion that occurs near high water 
is made very evident by these curves. 
If corresponding curves for 12 hours could have been obtained, 
they would probably have shown — 
(1) at the bottom, a minimum temperature after high 
water, and a maximum before low water, and therefore 
a steep rise. 
(2) near the surface, a minimum temperature before high 
water, and a maximum after low water, and therefore a 
steep fall. 
Fig. 2. Kincardine, 27th April 1886, from 10.30 o’clock to 17.30 
o’clock, i.e., from 2 hours ebb to 3 hours flood. 
