Physics of the Lakes:

All the lakes investigated are in enclosed drainage basins. Streams flow into the lakes but all loss of water is by evaporation. Therefore all, except a few such as Don Juan, covered with a layer of ice between [gap — reason: illegible] and 22 feet thick. Their density increased with depth, owing to an increasing and high salt content (up to 30[unclear: %] Nael).

These properties result in very little mixing of the water - [unclear: a phenomenon] which greatly simplifies the treatment of heat transfer in the lakes.

Instruments to measure temperature mount of sunlight density and salt concentration were lowered through 4 inch diameter holes drilled through the ice. Water samples were obtained from various depths by pumping through a hose. The principal measurements made were of temperature using thermocouples and a potentiometer. The temperatures always increased with depth near the top of the lake, in every case except one (Lake Veda) reaching a maximum between 10 and 30 feet below the bottom of the ice and then decreased with further increase in depth. The presence of a maximum temperature in the middle depths indicates that the heat producing the high temperature is not coming from the bottom. [unclear: quantitative] studies of the heat flowing out of the lakes by conduction and into the lakes as light, indicate that the observed temperature distributions are consistent with the theory that solar radiation is the main source of heat.

A summary of some of the properties of the acre important lakes follows.