of Edinburgh, Session 1884 - 85 . 55 
A sample of water was taken at the quarry mouth at high water 
daily, with such interruptions, sometimes of considerable duration, 
as were to he expected at the first starting of a piece of routine 
work not absolutely necessary, with a small staff. 
In July only three samples were taken, owing to a trip of the 
“Medusa” on the Clyde; their densities varied from 1 '02454 to 
1-02469. 
In August there were 21 occasions on which water was collected 
at the entrance, 13 at high water, and 8 at low water. The mean for 
the low water was 1 ‘02464, the extremes 1 '02478 and 1-02435. The 
only case of special interest is one on the 12th. On that day there 
was a severe thunderstorm with exceedingly heavy rain for several 
hours. In the middle of it, during low water, when the quarry 
was land-locked, a bottle was filled holding its mouth just under the 
surface, and another at a depth of six inches. The result was that 
the extreme surface layer of water was found to have a density of 
1 '02394, the other of 1 '02405, a difference of O'OOOll. The high 
water figures differed only from 1-02405 to T02496, the mean being 
1-02461. 
During September 21 samples were taken at the quarry entrance 
at full tide ; the mean density was 1 "02446, the extremes being 
1-02487 and 1 -02296. 
During this month a sample was taken up daily for some time 
at low water at a rock on the shore near the quarry. The mean 
density (12 observations) was D02461, the extremes D02506 and 
1 -02378, all higher than those at high water. The peculiarity of 
this result is emphasised when the curves are consulted, for there 
low tide is seen to produce a lower density beyond Inchkeith 
occasionally. 
In October four samples only were collected ; the mean density 
was D02319, the extremes being 1 -02391 and 1 '02193. 
During November the density was determined on nine occasions ; 
the mean was 1 '02313, the highest 1 '02390, and the lowest 1 -02035. 
In December samples were taken with greater regularity. They 
gave a mean of 1 -02052, with extremes of 1 -02449 and 1 -00969 in 
26 samples. 
The figures for November and December are plotted in curve G 
(Plate V.), which shows the great irregularities that were observed. 
