Mr. Cadigan.

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 beth 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 beth 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.

Mr. Eisenberg.

You mentioned before the thickness. How did you measure the thickness of the tape and paper?

Mr. Cadigan.

With a micrometer.

Mr. Eisenberg.

How sensitive is it?

Mr. Cadigan.

It reads to four places.

Mr. Eisenberg.

How sensitive?

Mr. Cadigan.

Four decimal places.

Mr. Eisenberg.

Is that one-hundredths?

Mr. Cadigan.

That would be one ten-thousandths.

Mr. Eisenberg.

And they were identical in that measurement?

Mr. Cadigan.

Yes; I measured both the paper sack, Exhibit 142, and the known I paper sample, Exhibit 677, at 0.0057 inch, that is fifty-seven ten-thousandths.

Mr. Eisenberg.

Go ahead, Mr. Cadigan.

Mr. Cadigan.

Do you want me to discuss this replica sack yet?

Mr. Eisenberg.

You mentioned a replica bag?

Mr. Cadigan.

Yes.

Mr. Eisenberg.

Could you explain what that is?

Mr. Cadigan.

Yes; this is Commission Exhibit 364. It is a paper sack similar to Commission Exhibit 142. It was made at the Texas School Book Depository on December 1, 1963, by special agents of the FBI in Dallas to show to prospective witnesses, because Commission's Exhibit 142 was dark and stained from the latent fingerprint treatment and they thought that this would--it wouldn't be fair to the witness to ask "Did you see a bag like that?" So they went to the Texas School Book Depository and constructed from paper and tape a similar bag.

Mr. Eisenberg.

This was made December 1?

Mr. Cadigan.

December 1, of 1963.