Mr. CADIGAN. Once it is in that machine then that wheel will mark the tape going through the dispenser just before it wets it and you paste it down. Mr. DULLES. Just before, generally just before it is used, then these markings are put on by the dispensing machine. Mr. CADIGAN. Yes, sir. After examining the papers, comparing them visually and under the microscope, I examined them under ultraviolet light. This is merely one additional step. Here again I found that both of them fluoresced the same way. Mr. EISENBERG. Could you explain the meaning of that? Mr. CADIGAN. Yes. Paper, along with many substances, has the property of absorbing or reflecting ultraviolet light rays differently. You can take two samples of paper and put them under an ultraviolet light, and they may appear to be the same or they may be markedly different. Mr. EISENBERG. You mean even if they look the same under visual light? Mr. CADIGAN. Visually they may look the same and yet under ultraviolet light there may be very dramatic differences. Mr. EISENBERG. What causes those differences? Mr. CADIGAN. Well, the chemicals that are in the paper itself; I think probably a very common example are the markings on shirts, so-called invisible dyes which, visually, you do not see, but you put them under ultraviolet light and the chemical is such that it glows brilliantly. So, it is basically a chemical or chemicals in there, in this case, in the paper being examined under the ultraviolet, which gives a certain visual appearance, which you can say, it is the same or it is different. In all of the observations and physical tests, that I made, I found that for Exhibit 142, the bag, and the paper sample, Commission Exhibit 677, the results were the same. Mr. EISENBERG. Can you just review those? That was the ultraviolet light---- Mr. CADIGAN. Well, briefly, it would be the thickness of both the paper and the tape, the color under various lighting conditions of both the paper and the tape, the width of the tape, the knurled markings on the surface of the tape, the texture of the fiber, the felting pattern. I hadn't mentioned this before, but if you hold a piece of paper up to the light, you see light and dark areas caused by the way the fibers felt right at the beginning stages of paper manufacture. There are light and dark areas, and these are called the felting pattern. This is something that will vary depending on how the paper is made, the thickness of the paper, the way that the fibers moved on the papermaking machine, and here again I found that they were the same for both the known sample, Commission Exhibit 677, and the paper bag, Commission Exhibit 142. Mr. EISENBERG. In all these cases, did you make the examination both of the tape and the paper in each of the bag and the sample? Mr. CADIGAN. Oh, yes. Mr. EISENBERG. And they were all identical? Mr. CADIGAN. Yes.