A STUDV OF TWIX LAKES. COLORADO. 



157 



6 8° 



10 12' 14' 16" 



6' 8° 10' 12° 14° 16° 



10 



12 



16 



18 



20 



22 



25 



Upper lake 



-. July 14. 1902. 

  • July 14. 1903. 



10 



16 



20 



22 



Lower Lake, 



— July 16. 1903. 

  • August 28. 1903. 



Fig 



Figure 3 represents two sets of observations on Upper Lake which were made 

 just one year apart. These curves show that down to a depth of 17 meters (55 feet) 

 the water was considerably warmer in 1902 than in 1903, and slightly warmer thence 

 to the bottom. 



Figure 4 shows the comparatively slight change in temperature that occurred in 

 Lower Lake between July 16 and August 28, L903. The upper stratum became 

 somewhat warmer and more thoroughly mixed, thus making the thermocline a 

 little more pronounced. In 1902 the surface water had a temperature of 17.1 C. 

 (62. 8- F.) on August L'l and a maximum of 17 on August 7. 1903. 



