430 TRANSACTIONS OF THE 



Mr. Tillman thinks Dr. Vanderweyde must be mistaken as to the Berlin 

 iron being of so yielding a nature. May there not be some other metal 

 associated with it, which gives it that property? 



Mr. Butler confirmed Dr. Vanderweyde's statement, and added that his 

 own specimens have considerable elasticity also. 



Professor Hedrick. — There must be a true chemical union between car- 

 bon and iron in steel, but the change from soft to hard steel, from non- 

 magnetic to magnetic, together with electric and many other changes where 

 no change of the chemical constitution occur, are properly referred to 

 molecular changes. This term molecular change is often used without any 

 definite idea being attached to it and apparently to cover up our ignorance 

 of the subject. It is not an explanation to say that a molecular change 

 has taken place. The ordinary hypotheses of chemistry are not sufficient 

 to explain certain phenomena. These we explain by referring thsm to 

 arrangements of the ultimate particles, or molecules, of a homogeneous sub- 

 stance whether these molecules be themselves chemical elements or com- 

 pounds. Chemistry establishes the principal facts upon which the other 

 natural sciences are built, but it does not furnish all the facts, and we 

 want a full statement. If practical experimenters would give all the facts 

 relating to their difficulties and failures, as well as those which resulted in 

 the success of their operations, we should often learn more from the former 

 than from the latter. 



Mr. Butler. — We should note our failures and record them, and chemists 

 ought to give this subject the attention its importance deserves. Our axles 

 break ; and but the other day the beak fell off one of our anvils, evidently 

 in consequence of a molecular change in its material. In this instance 

 there were spots of oxyd observed over the face of the fracture, for which 

 we could not account. 



Mr. Meigs. — Some persons explain the hardening of steel, by saying 

 that " the carbon in the metal is converted into ' minute diamonds' which 

 are embedded in soft iron, which cooling suddenly, contracts and allows the 

 edges of these diamonds to protrude." The whole subject should have 

 profound attention. Take a steel razor, and before using it on a cold 

 morning, pass its blade a few times over the hand, and observe the change 

 effected in its edge. Before it was comparatively blunt, now it is keen, 

 but who can account for the change ? 



Dr. Vanderweyde had tried many solutions of chemical agents, in place 

 of water, for hardening steel, but had obtained no satisfactory results. He 

 also succeeded in making a large compound magnet from sheet iron, by 

 simply case-hardening the poles and magnetizing the plates. This magnet, 

 when completed, was found to be very efficient as well as cheap. In answer 

 to a question by the president, he further stated, that a slight admixture 

 of aluminium improves iron. Also, that iron and other metals, generally 

 harden to some extent on being suddenly cooled. The metal of the Chinese 

 gong is an exception, for it must be cooled slowly. If we put a gong into 



