COLLECTIONS L\ ECONOMIC (JEOLOOY AM) M I T ALIJKCV. 



i';7 



Tlu' ]\\<i\i i»erceiitngoa were partly due to rohl h<immvrin<i and cold 

 rolliittj, and do not luoccod wholly tro.ii the additional woik hcstowcd, 

 as is shown l>v — 



These i)ercentaj:ea are the real values strictly due to the additional 

 work expended in rediicinfj the bars from 3 inch to fs inch stiuare. 

 Tlu' increased diictilit\ of the material resultin}^ from the processes of 

 manufacture, as evinced by increased contraction of area at fracture, 

 is presented in the following table: 



Series D. 



Ten tests were made to ascertain the increments of length, with cor- 

 res|)onding sets, un«ler a grailually increased ])nlling stress of rolled 

 steel ])lates of various thickness, containing 0.1.") of carbon. 



Two {dates of each of live ditfen'iit tliicknes.ses. viz, one-eighth, oue- 

 (juarter, threc-cightlis, one-half, and tive-eightlis inch were use<l. 



Series E. 



Ten tests were matic to ascertain the decrements of l-.-ngtli, with cor- 

 responding s«*ts, under a gradually increased thrusting stress, speci- 

 mens cut from same samples as series 1). 



