CLYDE SEA AREA. 



705 



There are thus two ways by which salt water and fresh "water may be brought into the 

 loch, and also two ways of escape for fresh water, by evaporation and by outflow. 



Table XXXIV. — Volume of Sea Water and Fresh Water in Loch Fyne at Different Dates, and 

 Amount of Rainfall or Evaporation between these Dates. 



Date. 



Sea 



Water. 



Per Cent. 



Cubic Sea Miles. 



Difference 



in Volume 



of Fresh 



Water. 



Cubic Sea 



Mile. 



Corresponding to Rain- 

 fall over whole 

 Drainage Area of 



Probable 



Actual 



Rainfall. 



Sea 

 Water. 



Fresh 

 Water. 



Sea Mile. 



Inches. 



Inches. 



April, 1886, 



June, „ 



August, 



^November, „ 



December, „ 



February, 1887, 



March, „ 



May, 



June, „ 



July, 



September, „ 



94-4 

 95-1 

 93-8 

 910 

 92-7 

 90-8 

 911 

 933 

 93-6 

 94-5 

 939 



0-4720 

 0-4755 

 0-4690 

 0-4550 

 0-4635 

 0-4540 

 0-4555 

 0-4665 

 0-4680 

 0-4725 

 0-4695 



0-0280, 



0-0245 



0-0310 



0-0450 



0-0365 



0-0460 



0-0445 



0-0335 



0-0320 



0-0275- 



0-0305 J 



- 



-0-0035 

 0-0065 

 0-0140 



-0-0085 

 0-0095 



-0-0015 



-o-oiio 



-0-0015 



-0-0045 



0-0030 



-0-000021 



0-000039 



0-000082 



-0-000050 



0-000056 



-0-000009 



-0-000065 



-0-000009 



-0-000027 



0-000018 



-1-5 



2-8 



5-9 



-36 



4-0 



-0-7 



-4-7 



-0-7 



-2-0 



1-3 



6-20 

 5-60 



1770 

 9-20 

 6-90 

 7-40 

 4-40 

 2-00 

 2-80 



11-20 



Mean, 



93-1 



0-4655 



0-0345 



Excess of 



Rainfall, . 



0-8 



Total, 73-40 



Table XXXIV. clearly shows that there is no tendency for the accumulation of fresh 

 water in Loch Fyne, the average salinity appears to come to a maximum in June and 

 July, the months of least rainfall and most evaporation, and then to diminish steadily to 

 the month of February at the period of maximum rainfall and minimum evaporation. 

 Evaporation is probably the most potent factor in carrying away any excess of rainfall 

 during the summer months. A great accession of fresh water on the surface must 

 necessarily, by raising the level, accelerate the ebb tide and so run off an excess of fresh 

 water with considerable rapidity. On the other hand, after a long dry spell the tendency 

 of evaporation would be to lower the general level and so accelerate the flood tide, thus 

 increasing the salinity from without. 



The Circulation of Loch Fyne. — In the action of the tide we may look for an explan- 

 ation of the tendency to get rid of superfluous fresh water which the observations show 

 to exist. The observations on tidal effects were not very numerous, and it would be well 

 to carry out a series of careful density determinations off Otter Spit, at frequent intervals 

 during a complete tide, both when the average salinity of the loch is exceptionally 

 high, and when it is exceptionally low. 



VOL. XXXVI. PART III. (NO. 23). 5 N 



