of the Fishery Board for Scotland. 



307 



The other stations are always influenced by the waters of the Tay and 

 the Forth, especially the Abertay lightship which floats in the freshest 

 water examined by the observers of the Fishery Board. But none of 

 them show so remarkable vicissitudes of density in 1893 as happened in 

 previous years, the range of density being considerably lower than usual : 

 this may be explained by the dryness of the spring and the absence of 

 very great floods. Rain and river water alter density much more 

 effectively than evaporation which, indeed, does not counteract their 

 influence in cloudy weather. 



CRUISER OBSERVATIONS. 



When observations were taken from the ' Vigilant ' or ' Jackal, - with 

 some regularity at any station, the results have been brought together in 

 Section III. of the tables ; and the more important stations have had 

 ten-day and monthly means calculated when there existed sufficient 

 observations to do so. At Rothesay the temperature in the winter 

 months, for which there are records, was much above that of 1892 and 

 considerably higher than 1891. In summer the exceptionally high 

 temperature of the other stations was also recorded here ; but September, 

 October and November of 1890 were considerably warmer than in 1893. 

 The surface water was generally warmer than that of the deeper water, 

 except in November, when it was a little cooler. At most of the stations 

 where any difference between surface and bottom temperatures was 

 observed, the upper layers were warmer in summer and cooler in winter 

 than those below. The Stornoway observations show a very marked 

 surface heating in June and July. The Invergordon observations were 

 made mainly in spring and autumn, and do not indicate jso clearly the 

 relationship of 1893 to other years. In August and October 1893 the 

 surface water at 9 a.m. was about a degree and a half warmer than in 

 1892, and in the afternoon over a degree warmer. 



' GARLAND ' OBSERVATIONS. 



The physical observations made on board the 1 Garland ' are among the 

 most valuable the Board possesses. They are tabulated at the end of this 

 report. The stations are indicated by numbers, and their positions for 

 the Forth and Tay Districts are shown on a map published in the Ninth 

 Annual Report. 



The transparency observations, which are made by the samejobserver, 

 and are therefore comparable, have been fully discussed in past reports. 

 The following table contains a summary of the results in 1893, which may 

 be compared with those of previous years. 



Mean Transparency of Water of Firth of Forth. 





Mean Transparency. 



Max. and Min. 



Station. 



West End. 



East End. 



West End. 



East End. 





Low 

 Sun. 



High 

 Sun. 



Mean. 



Low 

 Sun. 



High 

 Sun. 



Mean. 



Max. 



Min. 



Max. 



Min. 



I. 

 II. 



lit 



IV. 

 V. 

 VI. 

 VII. 

 VIII. 

 IX. 



x. 



2-4 

 27 

 2 1 



2- 0 



3- 3 

 29 

 19 

 3-6 

 46 

 17 



3-4 

 3-8 



3- 4 

 2-1 

 5-3 

 4 5 

 31 



4- 8 

 7-2 

 0-5 



2- 9 



3- 3 

 2-8 

 2-0 

 4 4 

 3 8 

 25 



4- 4 

 6 1 

 IT 



3-0 

 31 



2 1 

 22 



3 4 

 2-8 

 25 



4 4 

 50 

 18 



5 2 

 41 



3- 1 

 2 4 



5- 7 



4- 6 

 37 



6- 6 

 6-8 

 0-6 



3 7 

 37 

 2-6 



2- 3 

 47 



3- 8 

 31 

 5-7 

 (JO 

 11 



40 

 45 

 4 0 

 25 



6- 8 

 65 

 40 



7- 5 

 100 



40 



2-0 

 2-0 



1- 5 



2- 0 

 25 

 2-0 

 15 

 2-8 

 4-0 

 0 5 



5-5 

 5-0 

 3-5 

 30 

 9-0 

 70 

 45 

 75 

 9o 

 3 0 



25 

 2-5 

 1-5 



1- 2 

 2 0 



2- 0 

 20 

 40 

 40 

 0 5 



