14i F. Waldo — Bruckner 's Klimaschwankungen. 



(5.) In these particulars the partial river-lakes stand some- 

 where between the true river-lakes and the lakes without 

 outlet, 



A list of the times of maxima and minima before 1800 is 

 given for the Alpine glaciers and seven lakes, and for the 

 present century for the Alpine glaciers and 10 lakes in Europe ; 

 Caucasian glaciers and 12 lakes in Asia ; 10 lakes in JN". 

 America ; 2 lakes in S. America ; 6 lakes in Africa ; and 3 lakes 

 in Australia. As a result of a careful study of these data, 

 Bruckner finds that there is no law of retardation of epochs 

 (phases) as regards longitude or latitude ; but in general the 

 periods of high and low water occur simultaneously over the 

 whole earth. The period from maximum to maximum, or min. 

 to min. oscillates between 30 and 40 years, with an average of 

 35*6 years. If we are to judge of the climate by these oscil- 

 lations of lakes without outlet, we obtain the following little 

 table : 



Climate Climate 



Dry or warm or Wet or cold or 



dry and warm. wet and cold. 



Before and about 1720 "| Before and about 1740") 



" 1760 I . " 1780 



1800 I m f' « 1820 I m f I - 



1835 | Water " " 1850| Water - 



1865J " 1880 J 



A similar table of the times of maxima and minima of water 

 in 13 rivers and 13 river-lakes is as follows: 



Minima. Maxima. 



About 1760 About 1740 



1795 " 1775 



1831/35 " 1820 



" 1861/65 " 1850 



1876/80 



It is seen that these periods are about the same for all three 

 classes of bodies of water, and a common climatic cause must 

 exist on all continents. 



But these are in a measure indirect determinations of the 

 oscillations of those factors which go to make up climate- 

 Direct observations of rain-fall, temperature, etc., have been 

 made for a sufficient length of time to furnish material for 

 closer determination of changes of climate than that just men- 

 tioned. We will now summarize these. 



Rain-fall. — Bruckner has made use of observations at 321 

 points on the earth's surface, and distributed as follows : 

 Europe 198, Asia 39, North America 50, Central and South 

 America 16, Australia 12, Africa 6. It is seen that most of 

 these are in the northern hemisphere, but only those stations 

 could be used where the observations extended over a suffi- 



