Mr. Ball. I will show you four that are marked as—we will give these four an exhibit number. Do you know whether or not they were shells similar to that?
Mr. McDonald. Yes, sir; they were .38 caliber. Now, I didn't mark all of these shells, myself.
Mr. Ball. Did you mark any of them?
Mr. McDonald. I recall marking one.
Mr. Ball. The four cartridges, the witness is examining now we will mark collectively as Commission Exhibit 518.
(The articles referred to were marked Commission Exhibit No. 518 for identification.)
Mr. Ball. And there are two cartridges that have been marked as Commission Exhibit 145 that the witness is also examining. Now, on one of the cartridges that have come from Commission's Exhibit 145, consisting of two cartridges, one of these you identify as a cartridge with a dent in it?
Mr. McDonald. Yes, sir.
Mr. Ball. How can you tell this?
Mr. McDonald. From the center of this—of the primer there—it is a small indentation, and some of the metal is blurred or not polished.