of the Fishery Board for Scotland. 



395 



SECTION C— PHYSfCAL OBSERVATIONS. 



REPORT ON THE PHYSICAL OBSERVATIONS CARRIED ON 

 BY THE FISHERY BOARD FOR SCOTLAND IN THE 

 FIRTHS OF FORTH AND TAY, AND IN THE CLYDE 

 SEA AREA, AS WELL AS THE OBSERVATIONS MADE 

 ON BOARD THE CRUISERS < JACKAL ' AND ' VIGILANT ' 

 ROUND THE SCOTTISH COASTS. By Hugh Robert Mill, 

 D.Sc, F.R.S.E., and Andrew J. Herbertson. (Plate XVIII.) 



CONTENTS. 



1. General Summary for 1891-92 ..... 395 



2. Discussion of Observations made at Fixed Stations on the East 



Coast, 1891 . ....... 401 



3. Discussion of Observations made at Fixed Stations on the West 



Coast, 1891 . .... 405 



4. Discussion of Observations made at Fixed Stations on the East 



Coast, 1892 . . . . . . .407 



5. Discussion of Observations made at Fixed Stations on the West 



Coast, 1892 ........ 413 



6. Discussion of Observations made at { Garland ' Trawling StationSj 



1891-92 ........ 410 



7. Discussion of Observations made on board the Cruisers, 1887-92 . 422 



8. Tables, 1891 . . . . . . . .429 



9. Do. 1892 ........ 459 



10. Ten Day and Monthly Means, Cruiser Observations, 1887-92 . 482 



1. GENERAL SUMMARY FOR 1891-92. 



In this report, as in the last, peculiarities in the physical conditions of 

 the water have been specially noted, so that comparisons may be made 

 with the data collected by the departments concerned with the details of 

 the fishing. Much of practical value and of interest may be obtained by 

 an examination of these two sets of facts ; but the great use of the 

 physical observations can only be realised when a sufficient length of time 

 has elapsed to permit averages of some stability to be calculated, and 

 deviations from these determined. 



When the average conditions, both physical and biological, are known, 

 the occurrence of abnormalities in the former, which may be detected by 

 the fishermen, will, in all probability, denote variations in the latter. It 

 will be possible to calculate four or five year means for the longest 

 established East Coast station when the returns for the year 1893 come 

 to be discussed. 



