Abstract :
MR. RACKHAM : It has occurred to me in listening to this most interesting lecture, a lecture which is so out of the ordinary that it is more particularly interesting, whether Mr. Shaw considers it possible to lay down some specification for measuring surface roughnesses¿for instance, a British Standard Specification that might be adopted for that purpose. I remember that the firm with which I am connected required to older out a number of spindles with a polished finish. All we could really say was we wanted " polished finish." A very ambiguous term. The lecturer showed some Zeiss photographs of surface finishes. I am wondering to how many magnifications they were taken. Another thing that occurred to me was whether Mr. Shaw, during his lengthy investigations, has come across a particular metal or group of metals on which it is easier to obtain a highly polished finish. The methods explained for measuring surface finish seemed rather lengthy, and I am wondering whether there is a ready method from which one could judge the finish of an article without destroying it or even getting specimens from it.
