ENGELMANN MEAN & EXTREME TEMPERAT E IN ST. LOUIS. 497 



mile west of the river, lies in Lat. 38° 38' 03" and Long. 90° 12' 

 15" ; the low-water mark of the Mississippi is 379 feet above the 

 Gulf, and the foot of Market street (City Directrix) is 413 feet 

 above the same. 



My observations were made in the first twelve years on the 

 south-east corner of Second and Chestnut streets, only two blocks 

 from the river and 75 feet above low-water mark of 1863 ; for the 

 next 22 years on the south-west corner of Fifth and Elm streets, 

 five blocks from the river and no feet above low-water mark; 

 and for the last 1 3 years on the north-west corner of Thirtieth and 

 Locust streets, two miles from the river and 177 feet above low- 

 water mark. When 1 was absent from the city Dr. A. Wislize- 

 nus and lately Mr. B. D. Kribben have kindly filled the gaps. 



My instruments were at first such as could then be obtained 

 here ; soon I imported correct thermometers from Europe, and for 

 nearly 40 years I used those made by Jas. Green, then of Balti- 

 more, and soon afterwards of New York. * 



For many years the observations were made at different peri- 

 ods of the day, and especially at hours when the extremes might 

 be expected to occur, viz. at sunrise and at 3 p.m. ; and the maxi- 

 mums and minimums were selected from all of them, often eight 

 in a day, at whatever hour of the day they were found. Differ- 

 ential thermometers were observed only since the last i 2 yearg. 

 Thus I may not always have noted the absolute extremes of each 

 day, and my tables can claim only approximate reliability ; I 

 give them for what they may be worth, but I can assure my 

 readers that they furnish a record elaborated with zeal, conscien- 

 tiousness, care and assiduity, and for a length of time such as 

 probably few others, if any, exist in this valley. 



The arrangement of the tables explains itself The first two 

 columns represent the means of the 47 minimum and of the 47 

 maximum observations made on each day of the year, and the 

 third column the mean calculated from the two former. The next 

 "Min." column gives the lowest and the "Max." column the high- 

 est temperature ever observed on that day ; the column of years 

 next to these gives the year in which these extremes did occur. 

 The last column represents a supposed — or estimated — true mean 

 for the day after eliminating excessive extremes. 



The year has been divided into 73 periods of 5 days each, the 



