TRANSACTIONS OF SECTION G. 755 



continuous triple indicator apparatus which autographically records during a trial 

 the speed, variation, and dui'ation of the valve chamber pressure at any point of 

 the stroke. 



FRIDAY, AUGUST 20. 

 The following Ileport and Papers were read : — 



1. Supplevientarij Report on the Calibration of Instruments in 

 Engineering Laboratories. — See Reports, p. 424. 



2. The Strength of Columns. By Professor Gaetano Lanza- 



An attempt to compute the strength of any given column by the various rules 

 and formulae commonly found in different handbooks, and books written by so- 

 called authorities, will speedily reveal considerable discrepancies, not only in the 

 formuloe, but also in the results. 



Hence it becomes a matter of importance to make a careful study of the tests 

 that have been made, under practical conditions, on columns of such, sizes and 

 proportions as are used in construction ; for, whether we desire to adopt empirical 

 formulae or to endeavour to obtain rational ones, the final tests of all theories and 

 formulae must be whether they agree with the facts as shown by the results of 

 such tests. 



A summary is therefore given of the principal experiments that have been 

 made of columns of practical sizes. 



The greater part of the tests contained in this list were made on the United 

 States testing machine of eight hundred thousand pounds capacity, located at the 

 arsenal at Watertown, Massachusetts. The details of these tests are published in 

 special yearly reports issued by the Ordnance Department of the United States 

 Government. 



The following is the summary : — 



Cast-iroyi Columns. 



]. Tests of Metals, Watertown Arsenal, Reports of 1887 and 1888. 



•2. Bauscbinger, ' Mittheilungen aus dem Ktinigl. Mech. Tech. Lab., Miinchen," 

 Heft 12, 1885, and Ileft 15, 1887. 



The Watertown reports contain tests of eleven old and of five new cast-iron 

 mill columns. 



Bauschiuger tested the relative ability of cast and of wrought iron columns to 

 hold their otherwise safe load when heated to redness and sprinkled with cold 

 water. 



Wrought-iron Columns, 



1. Bouscaren, 'Eeport of Progress of Work on the Cincinnati Southern 

 Railway,' 1875. 



2. ' Transactions Am. Soc. Civil Engineers,' 1882. 



3. ' Transactions Am. Soc. Civil Engineers,' 1884. 



4. ' Exec. Doc. 12,' 47th Congress, 1st Session, House. 



5. ' Exec. Doc. 1,' 47th Congress, 2nd Session, Senate. 



6. ' Exec. Doc. 6,' 48th Congress, 1st Session, Senate. 



7. ' Exec. Doc. 3-5,' 49th Congress, 1st Session, Senate. 



8. ' Exec. Doc. 36,' 49th Congress, 1st Session, Senate. 



9. ' Tests of Metals, Watertown Arsenal,' 1888. 



10. ' Technology Quarterly,' vol. ix., Nos. 2 and 3, June and September 1896. 



Of these Nos. 2, 4, 5, 6, 7, 8, and 9 were made at Watertown Arsenal; 

 No. 3 contains a few tests where the columns were of practical sizes, together 



3 c2 



