THE FRESH- WATER LOCHS OF SCOTLAND. 



265 



of the loch, and the soundings show in certain places rather steep slopes 

 both off the northern and southern shores. 



Temperature Observations. In the following table are given the 

 results of a series of temperatures taken in Loch a' Chroisg on August 

 22, 1901, by Mr. Clark, and of two series taken by the Lake Survey 

 staff on August 1, 1902: 



The series taken in 1901 shows a range from surface to bottom 

 amounting to 10*7, whereas the two series taken in 1902 show a range 

 of only 5 in each case, and an extreme range of 6. The upper layers 

 of water down to a depth of 60 feet were much warmer in 1901 than in 

 1902, but between 60 and 100 feet the 1901 observations indicated a 

 fall of 9 (viz., a fall of 5-7 between 60 and 80 feet, and a fall of 3-4 

 between 80 and 100 feet), so that the temperature of the bottom layers 

 of water beyond 100 feet was lower in 1901 than was observed at these 

 depths in 1902. 



Seiche. On August 19, 1902, between 4.30 and 5.30 p.m., a seiche 

 was observed by Mr. James Murray within the shelter of the pier at the 

 east end of Loch a' Chroisg, a light west breeze blowing at the time. The 

 amplitude was a quarter of an inch, and the period about 11 \ minutes. 



Loch Gown (see Plate LVII.). Loch Gown (or Ledgowan) lies about 

 a mile to the south-east of Loch a' Chroisg, and is also a good trout loch, 

 but the fishing is preserved. It trends in a north-east and south-west 

 direction, is very irregular in outline, and about 1J miles in length. 

 Though it may at one time have formed a single lake, it is now divided 

 into two distinct lakes having, at the time of the survey, a difference 

 in level exceeding 2 feet. This separation has probably been brought 

 about mainly by the deposition of material laid down by the Allt 

 Mhartuin, and the passage between them is obstructed by weeds, 

 so that it is impossible to row a boat from one loch to the other, except 

 after heavy floods. The two lochs are nearly equal in superficial area, 

 but the southern basin is much deeper than the northern one. 



