ARTHUR KOEHLER, sworn as a witness on behalf of the State.

Direct Examination by Mr. Wilentz:

Q. Mr. Koehler, will you please tell us where you live and what your business is?

A. I live at Madison, Wisconsin, and I am employed there at the United States Forest Products Laboratory.

Q. Do you mean that you are employed by the United States Government?

A. I am.

Q. And what does the Forest Products Laboratory [F.P.L.] work consist of and what is your capacity there?

A. The work of the F.P.L. consists of making tests and investigations on wood. I am the expert on the identification of wood for the Government.

Q. Are you in charge of the Department?

A. I am.

Q. How many years have you done this work?

A. 21 years.

Q. How many pieces of wood do you examine a year for the Government?

A. Each year there are submitted from 2,000 to 3,000 samples of wood for identification which I handle.

Q. In your capacity has it become necessary for you to testify in court?

A. Yes.

Q. Tell us some of the best known cases you have testified in?

A. In 1923, I testified as an expert witness in the case of State of Wisconsin vs. one John Magnuson, a murder case.

Q. Did that involve the make-up of a bomb?

A. Yes. It involved the history of a piece of wood that was a part of that bomb.

Q. All right. In addition to your experience in the manner you have just indicated, have you had experience as a carpenter?

A. Why, I have worked on a number of carpenter jobs. My father was a carpenter by trade, had a large assortment of tools, and I have worked on the construction and repair of buildings and on cabinet work.

Q. Now, in the capacity in which you have been employed, will you tell me whether or not you have come into the Lindbergh case at the request of the Government and the State of New Jersey?

A. I did.

Q. And in that connection, have you inspected and examined this ladder on many occasions?

A. I have.

Q. I want to call your attention first particularly to what has been referred to as rail number – what is it, 16 or 19?

A. 16.

Q. Did you take off this rail 16, a part of exhibit S-211, for the purpose of investigations in the attic of the Hauptmann home?

A. I did.

Q. When did you do that?

A. I made the investigation on Oct. 9th, 1933, the first time.

Q. Having taken off this section, what did you find?

A. I found that the nail holes in it corresponded exactly with four nail holes in the joists in that attic and the grain of the wood in that rail corresponded exactly with the grain of the wood of the board next to it.

Q. Tell me whether there is or whether there is not a relationship between S-226, this piece of lumber here, and rail 19.
Mr. Pope: Object to the question. We say that this witness is not qualified to express an opinion regarding wood.

The Court: Do you say that he is not qualified as an expert on wood?

Mr. Pope: We say that there is no such animal known among men as an expert on wood; that it is not a science that has been recognized by the courts; that it is not in a class with handwriting experts or with ballistic experts. But this is no science, this is merely a man who has had a lot of experience in examining trees, who knows the barks on trees and a few things like that. We may say that the opinion of the jurors is just as good as his opinion, that they are just as qualified to judge whether there is any relationship between those two pieces of board as this man of experience as he terms himself.

The Court: I think the witness is qualified as an expert upon the subject matter.

Mr. Pope: May we cross examine him on that subject and see what his qualifications are?

The Court: You surely may.

Mr. Wilentz: If your Honor please, I have no objections to cross examination as to qualifications, but it seems to me that properly comes before the witness starts his testimony as to the matters before the Court. Now, we have qualified him and there was no objection to it.

The Court: I don't want to stand on form, Mr. Attorney General, and I don't think you do. You may cross examine him, Mr. Pope.

Mr. Wilentz: Before he does, may I ask that the counsel's observation about there being no such animal as a wood expert be stricken out; I am sure he didn't intend it.

Mr. Pope: I will withdraw it. It is just a homely expression, not meant with any reflection at all.

[After a recess, Mr. Wilentz continues his direct examination]

Mr. Wilentz: Mr. Pope, I will make an effort to qualify Mr. Koehler.

Q. Mr. Koehler, are you a graduate of any university?

A. Yes.

Q. Will you tell us what university, when you graduated, and the course of work you pursued there.

A. I graduated from the University of Michigan in 1911, where I pursued the course in forestry. Later on I took some post-graduate work at the University of Wisconsin in forest products and received the degree of Master of Science at the University of Wisconsin in 1928.

Q. Are you the author of any papers on the subject, and books?

A. Yes, I have written a number of government bulletins and a book.

Q. Can you read for us the list of publications of which you are the author so as to avoid the necessity of presenting all the papers except for the defense?

A. There are a large number here, 52 altogether. "An Improved Method of Infiltrating Wood with Celloidin," ...

The Court: Let me interrupt for a moment. Mr. Pope, do you still want to question this witness as to his expert qualities?
Mr. Pope: Will you allow us to confer?
Mr. Reilly: May we preserve our rights to this extent, and have the Court pass upon the witness's qualifications.
The Court: Yes. I would say to counsel now I deem this witness to be qualified as an expert.

By Mr. Wilentz:

Q. What are your duties at the F.P.L.?

A. One of my duties is to take charge of the identification of wood sent to the Federal Government for identification. If they are sent to a government office, they are supposed to be referred to Madison where I have charge of their identification.

Q. Do your duties also include the identification of wood in connection with crimes committed?

A. Yes.

Q. Now, sir, let me ask you again, - I show you Exhibit S-226 and I show you rail 16, and I ask you what, if any, is the relationship between them.

A. As the result of a careful study of the two, I have come to the conclusion that those two pieces at one time were one piece. They have been cut in two.

Q. Why do you say that they are the same piece and have been separated?

A. I personally took this rail, 16, from this ladder, which is the lefthand rail of the top section, and inserted cut nails into the nail holes that are in this rail.

Q. You are indicating four nail holes then: is that it?

A. Yes.

Q. Now what about them?

A. I took – those are cut nail holes – I took some cut nails, the cut nails which were removed from this board in the attic that has already been referred to. I placed them into the nail holes in this rail and those nails fit perfectly.

Q. Let me understand. You mean you took nails out of a part of the floor which is here in evidence, S-226, those very nails, and you then put them into those holes in this rail here, known as 16.

A. Yes. They fit perfectly. Then with those nails in those holes and projecting from the lower side, I took that rail and laid it over the joist in this portion of the picture shown in Exhibit S-215.

Q. When you say laid them on the joists, you mean just as they were as a part of the floor?

A. Yes. There were nail holes along the south side of the floor and I found that these protruding nails stuck into this rail fit exactly in the four nail holes which were in those joists.

Q. All right. Tell us what your opinion is.

A. In my opinion that rail had at one time been nailed down there on those joists, because it would be inconceivable to think – it wouldn't be possible that there would have been another board somewheres with cut nail holes in them, spaced exactly like these nail holes are in the joists, the same distance apart, the same direction from each other.

Q. Did it require any manipulation at all, or did they fit perfectly?

A. They fit perfectly. Not only as to the direction and spacing, but slant. One of these nail holes in here particularly is slanting, and the nail hole in the joist had the same slant.

Q. Is that the only reason for your opinion that rail 16 and S-226 were at one time the same piece of lumber?

A. When the rail and nails were inserted in the joist, the edge was perfectly parallel to the adjoining board.

Q. How do you explain the fact that when you put S-226 – No, when you put rail 16 on the joist as you have indicated – how do you explain the fact that there is a little distance, a half an inch, between the two floor boards?

A. That piece had been cut off.

Q. Tell us why you say so.

A. For one thing, this picture shows it to be found in the attic, that a saw cut had been made at the end of this [adjacent] board; in the adjoining board is a little cut right in line with the end of this board. Furthermore, there was sawdust on the lath and plaster of the ceiling below, right underneath the end of this board. Furthermore, this board projects over the joist. Now, a carpenter wouldn't let the end of a board lap over like that and hang free, he would put the joint right on the joists there, which also indicates that that was not the original condition.
Furthermore, by matching up the grain in this board in the floor and this rail from the ladder I find that the grain matches practically perfectly, considering the gap that is between the two.

[Mr. Koehler describes the matching of the convex "pitch streaks" of the boards, as well as the annual growth rings visible on their ends. They share the same number of rings, along with the same variation in width between the rings. The only discrepancy was caused by a knot, which "distorts the grain and the closer you get to the knot, the more the grain is distorted.]

A. (continued.) I can make this a little clearer if you want me to.

Q. I want you to.

A. To bring out more clearly the similarity between these growth rings in the rail and in the floor board I will take another photograph, which is a duplicate of that photograph marked S-232 [showing the knot in the board]. It is made of the same negative and to the same scale and matches up with S-232 perfectly.
I will take this picture of the end rail and cut it through the middle. Now I will take a portion of this picture and superimpose it upon the floor board.

Q. Take your time. What do you want?

A. Thumbtacks. Now, by taking these three narrow rings on this picture of the rail, and superimposing them over the three narrow rings of the picture of the floor board, you will see there is a practically perfect match.

Q. How do you explain the difference in color?

A. This ladder rail had been processed for fingerprints and some of the liquid ran into the end grain of the wood.

Q. I notice that the ladder rail is not as wide as the attic boards. Will you explain that, if you can?

A. In examining this ladder rail, I noticed that both edges had been planed with a hand plane. The plane was not in very good condition and left little ridges.

Q. I want to show you an exhibit in this case, S-177. Can you tell whether or not S-177 is the plane that was used in planing the ladder rail?

A. It was. When I plane a piece of wood with that plane it makes similar ridges of the same size and same spacing as is found on the ladder rail.

Q. Will you take this plane, S-177, and demonstrate to this jury what you mean by plane marks.

A. I will take a piece of wood which has been previously machine planed and is practically smooth. Now I will plane that with this hand plane and then make an impression of the marks made by that plane and also an impression of similar marks on the rail and show their similarity.

Mr. Pope: May I ask the witness a question, sir?
The Court: Certainly.
Mr. Pope: What kind of wood is that you are going to plane?

A. This is Ponderosa Pine.

Q. That is much different and much softer than North Carolina pine, different in grain and texture?

A. It is different from North Carolina pine.

Q. I submit if we are going to have any demonstrations at all, we ought to have a piece of N.C. pine planed, not a piece of nice soft poplar or something like that.

A. The same plane marks, hand plane marks occur on the rungs of this ladder and they are made of Ponderosa pine.

By Mr. Wilentz:

Q. And that is exactly the same type of wood as you have here?

A. Yes.

Q. Is the piece of wood upon which you propose to make the demonstration the same type, the same quality of wood that makes up these rungs of the ladder?

A. Yes.

Q. Have you the plane and will you give us a demonstration?

A. Yes. In order to make an impression of these plane marks, I employ a very simple method that I learned when I was a youngster. I used to put a piece of paper over a coin and rub a pencil back and forth over the paper and get an impression of the coin on the paper. I can do the same thing by putting a piece of paper over the plane surface, rubbing a pencil back and forth, and getting an impression of these marks made by the hand plane. Before I do that, however, I will take this piece of wood before I plane it and see what we get, so as to have something for comparison.
The Witness: If it is all right, your Honor, I would like to make the demonstration here, because this seems to be a substantial thing to work on (indicating the Judge's bench).
The Court: All right, so far as I am concerned.

Q. All right, sir. Mr. Koehler, if you want a little time now, we might ask for a recess, if it will take you a few minutes to get these pieces together instead of asking for it a little later.

A. It won't take long if it works all right first time. This plane is in such bad condition, I might have to try it a couple of times to get a satisfactory mark. I take it you wouldn't want me to do this planing during the recess time.

[Mr. Koehler conducts the demonstration.]

A. I have those three impressions fastened to one card. This white portion here was made on the block of wood before planing. This piece in the middle was made on the piece of wood after I planed it and this impression was taken off from one of the rungs of the ladder, rung Number 10. Now, if you will look along there, sight along there, you can see a number of lines on this impression from the ladder rung which coincide exactly with similar lines of these impressions made on the wood which I have planed. Look along it in a diagonal way (indicating).
[Mr. Koehler then introduces photographs of another, identical type of demonstration he had conducted during his examination of the materials. By using an enlargement of the photographs, he could more easily match the lines with existing nicks in the knife of the plane.]

Q. I want to show you State's Exhibit S-210, a chisel. Have you seen that chisel before?

A. Yes.

Q. What sized chisel was used in the construction of this ladder, if you know?

A. A three-quarter inch chisel was used in chiseling out recesses for the rungs.

[Mr. Wilentz attempts to link this three-quarter inch chisel to a quarter inch one of the same manufacturer found in Hauptmann's tool box. The three-quarter inch one was found on the Lindbergh property, allegedly under the nursery window. Mr. Pope objects, pointing out that any three-quarter inch chisel could have made the notches for the rungs.]

Q. Mr. Koehler, when did you first come into this case?

A. May, 1932.

Q. So far as salary is concerned, the State of New Jersey doesn't pay you any money for your work, does it?

A. No.

Q. So that since May 1932 you have conducted an investigation with reference to the identity of the wood that makes up this ladder?

A. Yes.

Q. The kidnap ladder, we call it.

A. Yes.

Q. You know from testimony in this case that the defendant Hauptmann was arrested in September 1934?

A. Yes.

Q. Prior to his arrest, had you ascertained where some of the lumber had come from?

A. Yes. In November 1933, I determined that some of it had come from the National Lumber & Millwork Co. in the Bronx. I traced some of the lumber in the ladder to the planing mill that dressed it and from there to the National Lumber & Millwork Co.

Q. How did you trace it?

A. I traced it by means of the planer marks made on the lumber when it was planed at the planing mill.

Q. Where did you go?

A. I went to the M.G. & J.J. Dorn Co., McCormick, South Carolina.

Q. How many companies are there that manufacture these planing machines?

A. Two in the eastern part of the United States.

Q. As a result of your investigation, did you find the machine which imposed those planer marks.

A. I did. At the mill of the M.G. & J.J. Dorn Co., McCormick, S.C.

Q. Having found the planer machine that made these marks, did you then follow the lumber that came from that mill, made in the shipment when that planer was used?

A. Yes.

Q. How many loads of lumber did you follow?

A. About 42.

Q. And finally did you get to this lumber company in the Bronx.

A. Yes. At the National Lumber & Millwork Co. in the Bronx I found one by four North Carolina pine in which the knife cuts made by the planer were exactly the same width as those on the ladder rail and also there was a defect in the planing on one edge and one side of the rail which I found on the one by four N.C. pine in the Bronx yard.

Q. How did you know, how could you know that the defect in those planer marks were made by the planer you found in the Dorn Co. mill?

A. That is a long story.

Q. We want the long story. Let's have it.

A. [Mr. Koehler describes the operation of a planing machine, number(s) of cutter heads both top and bottom, speed of feed rollers... As the cutter heads rotate, they make circular. If all knives are in good shape, no irregularities show up. If one or more have a nick or other defect, then each time it meets the wood, it leaves an impression reflecting that defect. If only one of eight cutters has defect, then a flaw will show up on the wood every eighth cutting, with only the speed of the feeder wheels determining the linear space between flaws. Misalignment of cutters may yield a deeper or shallower cut than the others.]

A. Therefore, by examining the surface of a piece of lumber, it usually is possible to tell how many knives there were in the cutter head that dressed the lumber, because as a rule there is something wrong with a knife somewheres, maybe a little nick in it or the knife may be out of line. In addition to these cutter heads planing the top and bottom of a board as it goes through the planer, there are similar cutter heads standing vertically on the two sides of the board and plane the edges of the board as it goes through the planer...
Therefore, having determined that this lumber passed through the planer at ninety-three hundredths of an inch per revolution of the top and bottom and eighty-six hundredths of an inch per revolution of the side heads, which meant that the side heads were going faster, because the lumber went all at the same rate of speed, and that there were eight knives in the top and bottom heads, and six knives in the side heads –now from an investigation of planers used in this section of the country on N.C. pine, which is the lumber used in the bottom rails of this ladder, I found that comparatively few planers are used in that section of the country having eight knives in the top and bottom heads and six in the side heads. The fact is I made a thorough canvas of all planing mills from New York City to Alabama. There are 1598 altogether, and I found only 25 firms that had [that configuration]. Two I could rule out because they did not dress one by four stock. I got samples from the other 23 firms, and I found that only one of those firms made revolution marks of the same spacing as on the ladder rail. All the others made wider of narrower revolution marks.

Q. What firm was that?

A. The M.G. & J.J. Dorn Co. in McCormick, S.C.

Q. Were you there personally?

A. Yes. I visited their mill and I found that when they ran lumber through their planer it made revolution marks exactly like on that ladder rail. The feed pulley is not standard and makes a distinctly individualistic mark.

Q. All right, sir. By the way, this picture, S-218, which also shows the Senator in there, Senator Dorn, does that show the cutter heads on it?

A. No, that shows the feed pulleys.

Q. The feed pulleys in that particular machine, the one you are talking about?

A. Yes.

Q. The one that the Senator has his hands on.

A. Yes.

Q. Having found the special pulley, what next?

A. That pulley was purchased in September, 1929; therefore that stock in these two ladder rails must have been dressed between October 1st, 1929 and the time of the kidnapping. They had shipped in all 45 car loads consisting in whole or in part N.C. pine 1X4 to 25 different firms, some receiving more than one load. Now this lumber in the bottom rails of the ladder showed some peculiar defects, due to an irregularity in the cutting edge of some of the knives in the machine.
Knowing that these knives have to be re-sharpened periodically, I knew that defect would not be found in all the lumber that was shipped out from that mill.

Q. In other words, you found because it had to be sharpened from time to time, all those 45 carloads would not show that distinguishing mark?

A. That is it.
[Mr. Koehler describes the unique marking, with spacing of 86-hundreths of an inch. After checking with a number of distributors, he found a match at the National Lumber & Millwork Co. in November 1933, after which he checked the purchase receipts of the company. More general questions about the lumber used in the ladder are forthcoming, followed by a few concerning the attic at 1279 East 222nd Street, New York City, Mr. Hauptmann's home.]

January 24, 1935
SEVENTEENTH DAY
ARTHUR KOEHLER resumed the witness stand:

Direct examination (continued) by Mr. Wilentz:

[Mr. Wilentz introduces the automobile Mr. Hauptmann was driving when arrested, along with a photograph of it.]

Q. Now, Mr. Koehler, have you seen this automobile?

A. Yes.

Q. Did you take this ladder and attempt to fit it into that car?

A. I did. When I took the three sections assembled and nested together, they fit in on top of the front and rear seats, and there were several inches to spare.
Mr. Wilentz: Take the witness.

Cross examination by Mr. Pope:

Q. Mr. Koehler, when you fitted the ladder in the car, did you lay it on top of the seats?

A. Yes.

Q. With one end on top of the rear seat, how near did it come to the windshield?

A. About four or five inches.

Q. And lying in that position in the car, it could be readily seen by anyone looking in the car?

A. Yes.

Q. You have told us that you have testified in numerous cases, among them you mentioned one, a murder case. What was the point involved in that case in your testimony?

A. A home made bomb was sent through the mails to a drainage Commissioner and when the Commissioner opened the package it exploded and his wife, who was standing nearby was killed. The hollow cylinder portion of the bomb was wood.
[Mr. Pope establishes that Mr. Koehler has testified in less than a half-dozen trials, all the others being civil cases dealing with branding of lumber, tensile loading in load failures, or disputes as to correct delivery according to specifications.]

Q. Now, you have never undertaken to identify chisel marks or plane marks upon lumber in court before, have you?

A. In court? No.

Q. This is the first time you have been called upon to testify to that?

A. Yes.

Q. Taking the structure of this ladder as a whole would you say that it was built by a mechanic or by an amateur or even less? It is rather a poor job, isn't it?

A. Yes.

Q. Even the sawing of the notches is poorly done, isn't it?

A. Yes.

Q. From your knowledge of wood, would you think that a ladder constructed as this one, would hold the weight of a man of 180 pounds under those conditions?

A. Yes, I think it would.

Q. And could he go up and down readily without the ladder breaking?

A. He might.

Q. He might.
A carpenter building a ladder of that kind would generally space the rounds about a foot apart, wouldn't he?

A. That is the standard distance.

Q. These rounds on all the sections of this ladder are spaced a rather wide distance apart, are they not?

A. Unusually wide.
[An extended discussion of lumbers and locations of mills ensues.]

Q. Just one or two questions about the milling machine. Did you determine at what speed the cutter head (with eight knives) was running on the planing mill in the Dorn mill in South Carolina?

A. Yes; 2700 revolutions per minute.

Q. That would mean that there were eight times 2700 cuts on the underside or the upper side of the board per minute, wouldn't it?

A. Yes. Wait a minute. Yes, that is right.

Q. About 22,000 cuts per minute?

A. Yes.

Q. Now the markings of a knife cut on the underside of a board going over a jointing machine or a planing machine depends whether or not there is any overlapping of the following knives, doesn't it, overlapping cuts?

A. Will you please repeat the question?

Q. I will put it this way to you. If a board is run across a planer head moving with eight knives at 22,000 cuts per minute, if it is moved at a fairly rapid rate of speed, the result will be a perfectly smooth board, won't it?

A. No. The faster it is run, the rougher the work it does.

Q. Isn't it the slow motion of a board across the planer that causes the ridges or ripples to show on the bottom of the board?

A. No. The slow motion brings them closer together and makes them inconspicuous.

Mr. Pope: Thank you very much, sir.

Re-direct examination by Mr. Wilentz:

Q. You said the ladder wasn't a good carpenter's job. It was some sort – are the tools a good carpenter's set of tools?

A. I wouldn't say so.

Q. Is the plane a good carpenter's plane?

A. No.

Q. Is the ladder a good carpenter's ladder?

A. No.

Re-cross examination by Mr. Pope:

Q. This type of ladder is a general plan and type of ladder used quite extensively in the South in the fruit industry, is it not?

A. Not to my knowledge. I never saw a ladder like that before.

Q. Have you ever paid attention to the type of extension ladder used in the fruit picking areas of the South?

A. I didn't know they used sectional ladders.

Q. You never noticed that?

A. No.

Mr. Pope: That is all. Thank you.
Mr. Wilentz: Mr. Koehler, that is all. The State rests.