Total solids 



Calcium 



Potassium 



20-9 



19'3 



20'9 



16-2 



7* 



16-7 



17-4 



7-7 



9* 



18-9 



14-2 



7-3 



17*5 



10-6 



o-o 



17-7 



14-5 



9- (loss) 



18-1 



12*05 



16*3 



242 D. T. MacDougal—The Salton Sea. 



eluded that the high, value found for the first year increase of 

 the constituents was largely caused by leaching of salts from 

 the bottom of the lake, as already stated. 



An inspection of the results of the analyses given above 

 shows that the calcium and potassium do not follow the course 

 of concentration of the total solids, or of sodium, the principal 

 constituent of the residues. The percentages of increase of 

 the total solids and of these two elements are as below : 



1908 .... 



1909. __ 



1910 



1911 



1912_ 



1913 



1914 



Nothing in the results obtained by a study of the Salton 

 yielded positive evidence as to the fate of the potassium, but 

 the deposition of the calcium on twigs and objects near the 

 surface of the water was observed as early as 1910, at which 

 time the concentration of this element in solution fell farthest 

 behind that of the other constituents. Furthermore the thick- 

 ness of the deposit now being formed on branches and other 

 objects at the surface is less than in 1910 and 1911, although 

 the actual concentration of the calcium is greater. Without 

 rehearsing the detail of this matter which is given in the 

 volume on the Salton, the deposition of calcium takes place 

 under conditions favorable to the existence of certain bacteria 

 and algse. These conditions in the Salton include a concentra- 

 tion of *5 to *6 per cent and the presence of some organic mat- 

 ter. The environment necessary for a plexus which would 

 have the end effect of precipitating calcium might be entirely 

 different in other cases, and undoubtedly is so in the Great 

 Salt Lake, in the water of the Atlantic, near the Florida keys 

 and in other places in which this matter has been studied. 

 The direct interest in the present connection is the probable 

 origin of the travertine which forms a coating on the rocks at 

 certain places near the ancient high level of Elake sea. This 

 layer is but a few inches in thickness near the high level, 

 increases to a point 30 to 40 feet below, then thins again. It 

 is as if Blake sea were full, then began to recede, the deposi- 

 tion of calcium increasing to a maximum rate when a certain 

 concentration was reached, then slowing down as concentration 

 continued. It is by no means certain, however, that such was 

 the case, and it may well be that the thickest part of the 



