664 MEMOIR OF REV. JOHN FLEMING, D.D. 
of contention among the geologists of that period. To neither of their theories 
could he assent, but boldly asserted his freedom, declaring that the true theory 
of the earth must embrace both, and paved the way for his friend Sir CHaruEs 
LYELL, who has won so many laurels in this independent field of inquiry. Not 
that they agreed on particular questions, but their general views were consis- 
tent, the chief difference between them being on the question of metamorphosis. 
While FLEMING taught that molecular changes were due to mechanical and 
chemical action, Sir CuarLes LYEu has held that heat was the principal agent 
in changing the structure of rocks. This paper on the mineralogy of the Red 
Head will well repay a perusal, more especially where he discusses the formation 
of the famous pebble beds which occur in the amygdaloidal rocks of the district 
around Montrose. 
FLEMING was proposed as a Fellow of the Royal Society of Edinburgh by Pro- 
fessor JAMIESON, Dr BrEwstTER, and Professor PLAYFAIR, and was elected on the 
24th January 1814. The first paper which he communicated was read on the 
17th June 1816, and is printed in its Memoirs. It contains his observations 
“On the Junction of the Fresh Water of Rivers with the Salt Water of the Sea.” 
From observations made at different states of the tide in the Firth of Tay, he 
proved that when currents of fresh and salt water come in opposition, the lighter 
fluid, or fresh water, will be raised upon the surface of the denser, or salt water ; 
and when the stronger current of the tide has reversed the direction of the 
stream, the salt water will be found occupying the bottom of the channel, while 
the fresh water will be suspended or diffused on the surface. That the sea 
water reaches a higher point of the river than the sensible qualities of the water 
at the surface would indicate, was proved by the occurrence of the Fucus vesicu- 
/osus in fructification on the beach of Flisk. He also found the coralline Zubu- 
laria ramosa of Evuis, and a Sertularia resembling the gelatinosa of Pawuas. 
Another fact he also established, that near land, more especially continents, the 
water of the surface of the sea contains less salt than the water at the bottom, 
and that this varies considerably in regard to summer and winter. During 
winter, owing to the larger amount of fresh water poured into the ocean, 
and the lessened evaporation, he found the difference to be as eighteen in 
summer to sixteen in winter, and this obtained as far down the Firth of Forth 
as Prestonpans. 
In the summer of this year (1816) Fiemine delivered a course of lectures on 
botany to the Cork Institution, Ireland, with a view to his permanently accept- 
ing the chair as Professor. On his return from Ireland, he communicated a 
valuable paper to the Wernerian Society on the ‘‘ Mineralogy of Cork,” in which 
he has briefly though clearly stated his views regarding the crystallization of 
minerals, more especially pseudomorphs. The phenomenon of some crystals pos- 
sessing a more determinate power of crystallization than others, even while con- 


