THE FRESH-WATER LOCHS OF SCOTLAND. 417 



The electrical thermometers were at first intended to furnish the 

 means of observing continuously radiation into and from the loch. 

 The apparatus was not altogether suitable for this purpose, and, being 

 the first installation of its kind in this country, many unforeseen 

 difficulties arose in the manipulation of the instruments, but never- 

 theless many valuable observations were made by its means. The 

 installation consisted of three platinum resistance thermometers and 

 a Callendar recorder. The boat-house of St. Benedict's Abbey was 

 made available to the Lake Survey by the Lord Abbot of the monastery, 

 and in it were placed the recording instruments. A four-ply cable 

 connected the recorder with the Rlwda, which was anchored at a 

 distance of about 300 yards from the boat-house. Many of the diffi- 

 culties which were experienced arose from this cable ; the strain of the 

 wind and the waves was constantly damaging it, and as the RJioda 

 swung round with the wind great care was necessary to prevent the 

 cable fouling with the anchor chain. On the Rlwda there were three 

 large drums, on which there were wound the leads for the resistance 

 thermometers. By these drums a thermometer could be lowered to any 

 desired depth, and then connected to the shore-cable by means of 

 mercury cup connections, and a continuous record of the temperature 

 at that depth could thus be obtained. It was intended to lower each 

 of the three thermometers to a different depth, and connect them 

 successively with the recorder, and so to get a series of readings at 

 these depths, but the sluggishness of the recorder made this method 

 of observation undesirable. 



Temperature observations were taken at various points along Loch 

 Ness. At times members of the survey were stationed at Invermoriston, 

 Foyers, Inverfarigaig, Whitefield, and Dores. At other times a steam 

 launch was chartered, and cruises made up and down the loch, taking 

 observations en route, but this method of observation was very slow. 

 The speed of the launch was about six miles an hour, and, as the loch is 

 24 miles in length, about eight hours were spent in steaming alone; 

 assuming that six series of observations were taken, each lasting over 

 half an hour, the observations at one end of the loch were taken six 

 or seven hours later than at the other end. It was found that in this 

 time the distribution of temperature in the loch might alter very 

 greatly, and therefore observations made in this manner might give a 

 very erroneous idea of that distribution. 



The observations in Loch Ness were discontinued by members of the 

 Lake Survey in September, 1904, but the work was taken over by the 

 monks at Fort Augustus (in particular by Father Cyril von Dieckhoff 

 and Father Odo Blundell), and continued by them until April, 1905, 

 so that the observations extend over a period of nearly two years. The 

 actual number of observations made in that time was about 12,000, 

 and these have been discussed by the writer in papers communicated 



DD 



