CLYDE SEA AREA. 155 



point to some definite cause. Gareloch came first 5 times and second once, out of the 



six columns in which it appeared, its total being 7. This is interesting in showing how 



the thermal changes in a shallow, brackish, and nearly land-locked basin were almost the 



same in order and amount as those of the freely-exposed Channel, where the complete 



mixture of water by currents entirely neutralised the evidence of depth, and the free 



communication with the ocean seemed to make up for the reduced effect of radiation on 



a clear water surface remote from land. Arran Basin came first on 2 occasions, third on 



2 occasions, and fourth 3 times, the total being 20. Dunoon Basin, with a total of 21, 



may be taken as practically the same. It was never first, but was second on 4 occasions, 



third on 1, and fifth on 2. Loch Strivan had a total of 26, Loch Goil of 30, and Loch 



Fyne of 37. In the last case the position was fourth on 2 occasions, fifth on 1, and sixth 



4 times. The order of restricted, range, retarded phase, and lowered mean temperature is 



thus, following the Channel : — 



1. Gareloch. 

 ( Arran Basin. 

 ( Dunoon Basin. 



4. Loch Strivan. 



5. Loch Goil. 



6. Loch Fyne. 



Depth is obviously a factor of some importance, or Gareloch would, not come first, but it 

 is a factor of very minor importance, or Arran Basin would not come second. The order 

 of the larger basins and. deeper lochs is obviously that of the degree of isolation due to 

 configuration of the basin, not alone to height of barrier, but to number of barriers, or 

 Loch Goil would not come before Loch Fyne. 



The contrast between the Gareloch and Loch Fyne is very marked — comparing them, 

 the former is found 0°'5 warmer on the surface, 1°"5 warmer in its mass, with a surface 

 range between the extreme months 2 0, 5 greater, and a range in mass temperature 6 0, 2 

 greater (almost double), with an average rate of change of seasonal temperature twice as 

 great, and with its period of cooling, compared with that of heating, nearly 40 per cent, 

 longer. 



Heat Transactions of the Clyde Sea Area. — So far the discussion has been limited 

 to changes of temperature, because to compare the actual amounts of heat involved in 

 the various transactions would be difficult without fuller evidence as to transverse 

 sections, and as to the specific heat of sea-water of different salinity. A few preliminary 

 calculations were made which may be placed on record, although they are but a rough 

 approximation. According to Professor Thoulet of Nancy, * if the specific hea/t of pure 

 water is taken, as unity, that of sea-water of density (As-se) 1 '00159 is 0*986 ; for density 

 1-01162 it is 0-957, while for density 1*02666 it is 0'931. The formula for expressing 

 the number of heat units in a mass of sea-water may be put as V x D x <r(t-t'), where V 

 is the volume, D the density, o- the specific heat, and t-t' the change of temperature. 



* Thotjlet, Oceanographie — Statiquc, 1889, p. 298. 



