of Edinburgh , Session 1885-86. 467 
water 9 h . 28. Depth 6 feet. Weather calm, thick mist; surface 
temperature 58° *0. 
The bottom water had a density of 1*014, and on our taking 
samples at every foot from the surface downwards immediately 
after this observation, the density was found only to increase from 
1 *000 to 1 *004. The withdrawal of the last of the sea water in a 
thin layer was observed in this case. 
VI. Ebbing Tide . — August 8, observations from 10 h .40 to 
12 h .O; high water 10 h .59. Depth diminishing from 9 feet to 
7 feet. Surface temperature 58° *0, 
Surf. 1 ft. 2 ft. 3 ft. 4 ft. 5 ft, 6 ft. 6 ft. 3. 6 ft. 6. 6 ft. 9. 7 ft. 8 ft. 9 ft. 
10h.40tollh.20, 1-001 1-001 1-001 l'OOl 1-003 1-003 1-011 1-013 1-015 1-018 
llh.25tollh.45, 1-0005 1-001 1-0015. 1*002 1-003 1-006 1-007 1-011 T018 ... 
llh.45to 12\0,* l'OOO 1*0015 1-0015 1-004 ... 1-009 
At 12 h .O the density at the bottom was 1*0035. 
VII. Ebbing Tide — August 21, observations from 10 h .30 to 
ll h .40 ; high water af 9 h .18. River much in its former conditions. 
Depth, 8 to 7 feet. Surface temperature 55° *8. All the observa- 
tions made from the bottom upwards. 
Surf. 3 ft. 6. 
4 ft. 
5 ft. 
6 ft. 
7 ft. 
8 ft. 
From 10h.30 to 10h.40 
. ... 1-001 
1*001 
1-006 
1-017 
1-023 
„ 10h.45 to 10J>.5Q 
. • 
1-007 
1-017 
1-023 
„ llh.0 tollh,5 
1*001 
1-017 
1-020 
„ llh.30 to llh.40 
• * ... 1*0005 
1-0005 
1-0005 
1-018 
The density observed in this set of experiments is plotted in 
Plate XIII. fig. 5, and the salinity is shown in Plate XIV. fig. 5. 
Tidal Variations of Salinity at the River Mouth. 
Taking the observations of No. III. at 16 h .55 as typical of the 
state of matters in the river at half flood, we may represent in the 
following table (Table I.) the calculated amount of salt present, and 
the ratio of sea to river water at each point. 
Table II. shows the same particulars for a typical case of the ebb 
tide, that recorded in No. VII., ll h .0. 
From the bottom upwards. 
