FISHERIES OF ALASKA, 1908. 53 



Weather, temperature, and other observations. — There was said to be 

 more snow on the mountains in the spring than at any time for many 

 years. There was a corresponding heavy run-off with the advance of 

 spring, causing unusually high water in the lake. This increased the 

 difficulties of racking the river or lake, as the gear had to be installed 

 at the highest stage of water. The weather during the summer was 

 unusually pleasant considering the region. There was a maximum 

 of sunshine and a number of successions of several bright clear days. 

 There was no great amount of rain nor many heavy storms, though 

 several good blows occurred, notably on July 17. 



There is no appreciable rise and fall of the lake due to ordinary 

 daily tides. At the foot of the lake, however, where the river begins, 

 the effect of the tide is always noticeable in modifying the outflowing 

 current and at the narrowest channel, at the Indian village, marking 

 the origin of the river, each tide probably always making a differ- 

 ence of level. On May 31 high tide nearly made slack water at this 

 point. By July 20 the lake had fallen sufficiently so that even at 

 the rack at the head of the lagoon the high tides slacked the current 

 appreciably. On July 23 a measurement showed that no noticeable 

 rise accompanied the slacking of the current. Navigation of the 

 river to the lake, even with gasoline launches of light draft, must be 

 made on high tide, as there are many shoals to pass. At the end of 

 the season, August 10, the lagoon itself was difficult to pass with a 

 draft of 4 feet. It required the extraordinary high water of a spring 

 tide to get the pile driver and ark out of the lake with the launch, 

 which draws about 4^ feet, at the close of the operations. 



From the ark and pile driver at the lake, air and water tempera- 

 tures were taken from June 14 to August 9, and the fall of the lake 

 level was measured almost daily. The lake must have reached its 

 highest level about June 15, and have held at this point until about 

 June 27, when it began to fall, as shown, by a mark placed on one of 

 the piles. The ''lake level" record in the table refers to inches below 

 this high-water mark. The fall to August 9 was 43 inches and the 

 lake was still falling when observations were discontinued. Thus 

 a fall of 3i feet had to be provided for in constructing and locating 

 the gate for the passage of salmon. 



Maximum and minimum thermometers gave all the air tempera- 

 tures. They were placed in a sheltered position on the pile driver. 

 The maximum air temperature observed from June 14 to August 9 

 was 79°, June 24 and 29; the minimum, 35° on June 20 and 21. The 

 maximum water temperature observed was 56°, the minimum 41°. 

 The water temperatures were taken at the surface with a metal 

 pocket thermometer, from the deck of the ark. The water at this 

 point was subject to rather sudden and unaccountable variations, 

 as shown, for instance, between June 24 and 25. Not far above the 

 ark is a shallow resrion between an island and the mainland. The 



