84 CARNEGIE INSTITUTION 



on three of the nights to take the car to Echo mountain and make 

 additional tests with the 1 6-inch telescope. 



The top of the Incline and the I^owe Observatory can be seen 

 from Inspiration point. During mj^ stay at the higher station I was 

 constantly above the fogs which had hindered me so much at Echo 

 mountain. They did not, during this period, rise to my elevation, 

 4,500 feet, but very often did cover L,owe Observatory all day long. 



The telescope was erected at Cuyamaca on May 27, and taken down 

 on the afternoon of June 5. Observations were made at intervals 

 during the day, from shortly after six o'clock in the morning till the 

 middle of the afternoon, and then again during the earlier portion 

 of the nights. The results were not at all favorable. The seeing 

 was nearly always poor, occasionally good, but never excellent. 



The San Diego Flume Company has kept a record of the weather 

 conditions at Cuyamaca dam almost continuously since 1888. I 

 made some examination of this record, and from it derived consider- 

 able information respecting the weather conditions which prevail in 

 this region. 



The readings of the maximum and minimum thermometers show 

 that the daily range of temperature is usually large, and that the 

 weather sometimes becomes very cold in winter and very hot in 

 summer. In winter the temperature occasional!)^ falls several de- 

 grees below zero, and in summer it may rise above 100°. Thus, in 

 June, 1899, there were five successive days with maximum tempera- 

 tures of 104, 108, no, 105, and loi. The minimum temperatures 

 for the same days were 50, 46, 55, 55, and 54 degrees. The highest 

 temperature noted in the record is 113 degrees. 



The rainfall is heavier at Cuyamaca than at any other place in 

 San Diego county. The heaviest snows also occur here upon the 

 peaks, sometimes amounting to a depth of several feet. Even about 

 the lake, in the little valley among the peaks, the snows are heavy. 

 At one time last winter 30 inches lay upon the ground for six weeks, 

 and ice formed on the lake to a depth of 8 inches. Here, as in 

 other regions adjacent to the desert, water cannot always be counted 

 upon from the melting of the snow. A warm dry wind may lick up 

 the moisture and carry it away, leaving scarcely a trace. 



The heaviest rains at Cuyamaca come in winter, but there are 

 also local thunder showers in summer. During the last days of my 

 stay in this region, I saw at a distance a number of these showers. 

 It is said, however, that they are sometimes productive of very 

 heavy rains. The prevalence of cloudiness in connection with these 



