The Laws Observatory. 517 
entire distance was gone over twice and the results of the 
direct and reverse levels differ by only 2.2 inches. The de- 
gree of accuracy thus indicated was attained in spite of the 
distance and the hilly nature of the country, and the result 
gives 143.03 feet as the elevation of the Observatory Bench 
Mark above Mo. Riv. Com. B. M. 354. Adopting 412.714 
feet as the elevation of the St. Louis City Directrix we have 
as the elevation above sea level, of the Paparaciii Bench 
Mark, 737.41 feet. 
The Observatory Bench Mark is a cross, cut in the west end 
of the stone sill of the north basement window of the 
Observatory building. 
The foregoing results for the elevation of the Observatory 
B. M. may be summarized as follows :— 
From R. R. levels, 731 feet. 
From Barometric Obs’ns, 739 feet. 
From Spirit Levels, 737.41 feet. 
The first two determinations serve merely as a rough check 
upon the last, and we have as the adopted elevation above sea 
level of the Observatory Bench Mark — 
737.41 feet. 
Mr. Williams and Mr. McCrary determined the elevations 
above sea level of several other points on or near the Univer- 
sity campus. For convenience of reference they are inserted 
ere. 
Height ot 
Sea Lev 
Observatory Bench Mark.........sceseeecceeccce rece seca seeees 737.41 eat 
- M. on water-table of Physics and Engineering Building..----- 745.73 * 
B. M. on water-table of Chemical Building........--+++++e+ee> ++ 746.61 *§ 
M. on water-table of Experiment Station... -+--+--++++++++- tials 
Front door-sill of Boone County Courthouse...---+++-+-++ sere 761.08 ‘6 
Issued May 1, 1894. 
